Author Topic: Hick Crank Overhead engine  (Read 10418 times)

Offline AVTUR

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Hick Crank Overhead engine
« on: August 02, 2019, 12:07:11 PM »
My work on the Boulton & Watt Bell Crank engine is coming to an end with just a little painting and the base to finish. These will be done in the autumn and I will post pictures and comments on the forum before Christmas. To fill the gap between now and the return to the Maudslay Table engine design, when winter forces me out of the workshop, I am starting work on a model of a Hick Crank Overhead engine.

I bought the kit of castings six years and was not impressed with the quality of three of the castings. Also one small casting was also missing. I saw it as a difficult project with many fiddly bits so I wrapped it all up in anti-corrosion paper and bubble wrap, put it in a plastic box and found room for it on a shelf. Every so often I have taken a look at it, to see if anything had changed, and thought about having a go at it.

The original engine, a compact 10HP engine, was shown at the Great Exhibition of 1851 by Hick, Hargrave & Co of Bolton. In 1956 Geoffrey K King (A.M.I.C.E., A.M.I.Mech.E, A.M.I.E.I, Mem: Newcomen Society etc.) drew up a 1/12 scale drawing of the engine which is the basis of this model. I do not know if he ever made a model but some have featured on YouTube etc and one was displayed at the Bristol model engineering show a few years ago. As yet there are no instructions available for the engine build.

I find myself very critical of the quality of model engineering drawings. I have to admit that with the advent of CADs they have improved. Geoffrey King’s drawings are quite good but he has crammed an awful lot on small sheets of paper. I can forgive the use of fractions and first angle projection but I have never found the latter easy. I have got into the habit of redrawing all model parts to my satisfaction using decimal dimensions and third angle projection. This leads to a better, or at least quicker, understanding of parts and machining operations. So far, last year,  I have redrawn most of the castings.

It would be nice to show general arrangement drawings and pictures of a model of the engine but the only ones I have are copyrighted. I have found a picture of an engine, attached, on the internet which is in the public domain. It shows the top of the engine. The cylinder and steam valve are hidden by the plinth.

More will follow.

AVTUR
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Offline b.lindsey

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Re: Hick Crank Overhead engine
« Reply #1 on: August 02, 2019, 02:51:31 PM »
Should be a very interesting build to follow AVTUR.

Bill

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #2 on: August 11, 2019, 05:13:16 PM »
I have now inspected the castings:
1.   One bearing block cap casting is missing so I will have to machine one to shape from bar stock or an odd lump of gunmetal.
2.   One bearing block has been replaced by a lump of gunmetal. This is not a problem since the block can easily be machined from stock.
3.   The edge of the casting of one standard has run into the fancy Egyptian decoration, see attached photograph. I feel that this is important and needs correcting: Small models need something that catches the eye. An awful lot of models displayed at shows, however good, don’t have a “look at me” appeal. The only things that stand out on this model are the standards and the complexity of the small moving bits.
4.   Other than the above all the castings are above drawing/machining size.
5.   All the iron castings can be touched by a file.
6.   The bedplate is an aluminium casting and the fillets are messy, see attached photograph. This will require careful work with a file, Dremell or ball end cutter. I fear that the aluminium will be sticky and nasty to machine.

I am happy with the above and have painted the castings with marking out ink (sometimes I wonder why, I guess I wanted to). I have started filing the castings smooth, to get rid of mould lines, risers, etc. They will then be shot blasted to give a controlled rough finish.

The redrawing of parts, starting with the castings, is progressing. As stated earlier this leads to an understand of the parts. After the completion of each drawing the required tooling (drill, cutter, tap and die sizes), fixings and fixtures are recorded along with any obvious difficulties. Some problems have become apparent:
1.   Strange BA sizes, 9BA nuts and screws are required. Fortunately I have found a firm that stock these. 9BA taps and dies are also available from a few places.
2.   A 7/64” slot cutter is called for. I don’t think they exist but there is an obvious work round.
3.   There are a number of 3/64” wide slots. Although such slot cutters appear not to exist one can buy 1,0mm slot cutters for about £25 each (how many am I going to break). This is one reason for my interest in an EDM machine. Another option, as discussed elsewhere, is to use a piercing saw and a very small file.
4.   The layout of the cylinder to steam chest fixings is too large (the first drawing mistake).

On the plus side I have not found any fixings smaller than 10BA.

The original drawings were made before the advent of modern anaerobic adhesives. Quite a few fixings are captive and these can probably be replaced using Loctite. In addition keys have been used on shafts. I see no point in using them except for show.

More will follow

AVTUR
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Offline Jo

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Re: Hick Crank Overhead engine
« Reply #3 on: August 11, 2019, 05:23:50 PM »
I would use M2 rather than 9BA  ;)

Is this the same Hick Overcrank Engine that has recently become available from Hemmingway as a set of castings and drawings ? I have attached the Hemmingway GA so you can see if it is the same engine. In case anyone feels the need to build one of these engines the castings are available from Hemmingway here: http://www.hemingwaykits.com/acatalog/Hick___Son_Overhead_Crank_Engine___G_K_King.html

Jo
« Last Edit: August 11, 2019, 05:41:31 PM by Jo »
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #4 on: August 11, 2019, 05:51:37 PM »
Jo

It is the Hemingway kit. I do not know if they have had any castings made recently.

I did not post the picture for fear of copyright.

AVTUR
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Offline Jo

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Re: Hick Crank Overhead engine
« Reply #5 on: August 11, 2019, 05:58:24 PM »
I did not post the picture for fear of copyright.

Yes the image would be covered by copyright law. But copyright allows the sharing of a reasonable amount of a design for the purposes of discussion and I am sure Kirk will be more than happy if your documentation of your build results in additional sales of his castings, which I have provided a link to  ;)

Jo
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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #6 on: August 11, 2019, 06:47:33 PM »
1.2mm milling cutters can be had fairly easily, MSC have several to choose from, I'm sure the extra 0.01mm over 3/64" won't be a problem.

As Jo says M2 fixings with old style hex proportions would be easier to source as well as taps & dies

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #7 on: August 18, 2019, 01:27:04 PM »
First: Many thanks to Jo and Jasonb concerning the picture of the model, 9BA threads and 3/64” cutters. I want to keep BA and ME threads since I do not like mixing different thread forms (or many forms on a project), seen too many bodged motorcycles. I am actively looking at the small cutters and have asked questions elsewhere on the forum. There may be more questions.

The fettling of castings has started. I got one fettled casting, the cylinder, shot blasted at “work”. I am just about happy with the result but filing marks will have to be finer (photographs attached). I do not have an air supply in my workshop so I have to rely on favours. The bedplate, its quality concerned me, is cleaning up very nicely. However I fear my Dremell may be reaching the end of its life. It was bought impulsively about 10 years ago and languished on the shelf for quite some time. About four years ago I found it made a good fettling tool and then, later, used it for parting-off very small items in a lathe.

During the fettling I found that the pump valve body casting (drawing attached) had a well-undersized dimension and that it was the mirror image of the drawing. The latter is of no consequence since it can be reversed without affecting anything. The undersized dimension has caused some thought:
1.   Do I try to squeeze the lost 0.05” into the remaining casting? I don’t really want to try.
2.   Do I machine a new one out of bronze bar? I don’t have any bar large enough although this is a sensible option.
3.   Do I build-up the casting by silver soldering a bronze pad onto the offending face? This is the likely option since I have small pieces of bronze and I like silver soldering.

This difficulty has uncovered a mirror drawing fault: the holes for the two studs that hold the valve body to the pump are also mirror imaged.

The drawing and understand of the components is continuing. More details and discoveries will be communicated later. I am itching to start machining.

AVTUR
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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #8 on: August 18, 2019, 03:24:10 PM »
Depending on whether it is short at the bottom or top you could rearrange things so the error evens out a 0.025" top and bottom. As the part is not seen and I doubt you will be using it as a boiler feed pump that should not be an issue.

The soldering option would work too if you want to keep to the original sizes again depending on where the metal is missing either build up the top or bottom or if it is generally undersize all over then put a two bits top & bottom.

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #9 on: August 26, 2019, 04:48:04 PM »
It has been a week of minor disasters and difficulties.

The drawing of parts has progressed well enough for me to take a break and start making bits. I have not found any more errors other than one missing dimension.

Fettling is continuing and I have had a few more castings shot blasted [photographs attached]. The first “nasty” happened I tried to speed up the fettling of one of the two standards using the milling machine (I had to remove about 0.04” of material to get the correct outline of the casting). Holding the casting in the vice was difficult because of its shape. I convinced myself that it was held tightly and rigidly, even tried to dislodge it with a good tap from a small mallet. The cutter spat it out of the vice on the second cut resulting in some superficial cut/gouge marks on the casting. These will be filled with epoxy resin.

After shot blasting I skimmed the base of the bedplate [photograph of set-up attached] to get a flat base for the machining operations on the top surface. As feared, the aluminium was sticky and I had treated it as good aluminium bar. The finish was not good but no one will see it. Returning to it after three days I discovered two problems:

1.   The drawing distance across the bedplate for the model mounting holes could not be met. The drawing dimension is 3.250”, the maximum obtainable was 3.063” [see attached photograph]. So the holes were drilled 3.063” apart.

2.   The casting had bowed. On the long edges the mid-point was about 0.04” below the ends [see attached photograph]. Casting can stress relieve themselves and move when first machined but this magnitude was a surprise. Thinking about it the options were
a.   Make a second skimming cut – unwise, it might exacerbate the distortion since one is removing material from the stiffest part of the casting.
b.   Do nothing and see what happens (if the movement continues).
c.   Ignore the bowing since it can be lost by mounting the model only at the mounting holes. Skim the top pads carry which the cylinder and standards. Hopefully any resulting bowing will correct the shape. This will then require further skimming of the pads (the pads are thick enough to allow this). If there is no movement so much the better. Obviously the pads for the standards must be flat relative to each other so that the standards are parallel.
I decided on option c.

I skimmed of the pads (a largish diameter cutter, lower than normal speeds and white spirit gave an adequate finish), enlarged of the two major holes and drilled and tapped of small holes without any problems [see attached photographs]. I always use a guide for manual tapping, both for tapping and removing the tap. In this case the tapped holes are for studs so the small holes, 8 & 10 BA, were not through tapped. I could feel the tap tightening up as it approached the hard skin at the other end of each hole (discretion is the better part of valour, etc). Geoffrey King used trapped bolts to attach the standards to the bedplate. In this case I don’t why know he did this so I am using 4BA studs instead. The tapped holes are smaller than King’s square holes so I can revert to his design if necessary.

On inspection I found that the width of the large hole was well outside the nominal dimension. At work we had a 3Fs mantra – Fit, Form and Function. Function has not been compromised. Fit may improve the fitting of the cylinder. Form, very important on a model, may be slightly compromised at the base of the front, cylinder, standard. This can be hidden be a little bit of cosmetic machining [photograph of finished bedplate attached]. The studs, blacked, will be fitted later.

Now to clear up this morning’s silver solder session. There will be more next week.

I have to apologise for not including a scale in the photographs. Hopefully I will remember to do so from now on.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #10 on: September 01, 2019, 05:59:07 PM »
I seem to have done very little this week. Part of this is due to me deciding that the week started on bank holiday Monday instead of Sunday.

I had a good silver soldering session. This I do outside on the garden patio because I do not want to incinerate the workshop and bikes due to the heat involved. Planning a session involves much watching of weather forecasts for a dry windless (less than 10 mph) few hours.

I soldered two parts for the model: the Valve Spindle Crosshead (details later) and the correction to the Pump Valve Body. I decided to pad out the face since I feel that if it can be seen, it will be seen and should look correct.

I have finished the basic Pump Valve Body but not the Screw Caps. The only difficult encountered was facing a valve seat. Again it was me being a bit gung-ho. I attach a drawing showing the passages in the body. Geoffrey King drew conical valve seats as shown in the drawing with an overall cone angle of 90°. I tried to work out a way of cutting these and almost started attacking a short rod of silver steel before wondering why he had used cones. Drawing the arrangement I found that the ball did not sit on the cone but on the lip formed by the cone and passage, just like a conventional arrangement. So I used the latter. The lip was formed by a slot cutter and machine reamer. The slot cutter bit on the first attempt, not badly. Once I had held it properly, not in a Jacobs chuck, removed the rake on the cutting edges and locked everything on the milling machine there were further difficulties.

The Bedplate has remained stable since the pads were skimmed eight days ago. I don’t think I will try to remove the bow in the bottom surface.

The workshop that does my shot blasting has a two week power outage starting in ten days time. Therefore fettling the Standards has become the priority.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #11 on: September 08, 2019, 06:21:07 PM »
I have finished fettling the Standards. The damage from the cutter described a few weeks ago has been filled with epoxy resin and smoothed out. Now to get them shot blasted on Tuesday.

The weather forecast promised today would be nice, fine and windless. Therefore the last few days have been spent getting parts made and ready for silver soldering. Soldering was done this morning and I am happy with the results. I will give more details when I finish each part or assembly.

I am giving the assembly of the model, and the necessary data, much thought and will try to describe assembly sequence in the next few weeks.

AVTUR
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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #12 on: September 08, 2019, 07:23:00 PM »
Do you find the filler is robust enough not to be removed by the shot blasting?

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #13 on: September 10, 2019, 05:21:52 PM »
Jason

About nine years ago I used JB Weld on an aluminium casting that was later shot blast. The JB Weld survived so I had some confidence. I had less in the actual stuff I used, it was nine years old. I believe epoxy has a shelf life.

The shot blasting was done this morning and again the JB Weld survived (photograph attached).

AVTUR
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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #14 on: September 10, 2019, 06:26:32 PM »
Ah, yes the JBweld is a lot harder than the usual car body type epoxy filler so I can see why that was OK.

Funny enough I was looking through some old Model Engineer mags the other day from the '80s and the decorative pattern on the top of the standards was also poor on those just like yours, The builder milled them off and then used a small ball nose cutter to do new ones.

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #15 on: September 10, 2019, 07:07:41 PM »
The decorative feature on the top of the standards is a poor example of the casters' skills. It was one reason why I put the castings aside a few years ago.

I am not sure how, or even if, I am going to correct them. They have already been sharpened up with a file during fettling.

AVTUR
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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #16 on: September 10, 2019, 07:45:32 PM »
I think I would mill off the raised vertical details and then go a bit deeper over the whole area. Then machine up a couple of flat strip to fit that can have a series of grooves cut into them and stick them in place with JBWeld. This gives nice square ends unlike the ball nosed cutter option.

Offline Johnmcc69

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Re: Hick Crank Overhead engine
« Reply #17 on: September 10, 2019, 07:48:46 PM »
That's a shame. Cool little feature.
 I like Jason's idea about using a ball end mill there.

 Good progress though!  :ThumbsUp:

 John

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #18 on: September 16, 2019, 12:40:05 PM »
After getting them shot blasted I have been giving the standards much thought. So much so that I put pen to paper (fingers to keyboard) so that I do not confuse myself. In the manner of a student to puts the longest, most complex equations into his/her presentation of work to hide the fact that he has done nothing, my ramblings are as follows:

The front standard has two bosses for the piston rod guide.

Function
1.   To hold the crankshaft assembly
2.   To locate the piston rod by means of a guide block
3.   To hold the governor spindle bracket
4.   To hold the rocker shaft

Fit: Datum 1 - Horizontal plane provided by base of standard, Datum 2 - Vertical plane provided by face of rear edging on standard, Datum 3 - Vertical plane of symmetry. These planes are orthogonal.
1.   The height from base to plummer block face must be 5.125” ± ?”. The faces must be flat and parallel.
2.   The shelf on the inner face of the standards must be flat for the governor spindle bracket mounting collars.
3.   The face of the piston rod guide bosses must be flat and square to the standard base.
4.   The face of the rocker shaft bearing pads must be flat and square to the standard base.
5.   Holes in bases and for plummer blocks must square or parallel to the datums.

Form is all important, looks count for everything. As far as possible both standards should be identical. I would like to have kept the finish as cast but the casting was so poor. Therefore I think they will be machined all over except for the large recessed surfaces which will remain as cast. I want to keep the height of the edging from the outside recessed surface constant if possible. The finished results may be shot blast again. The frieze at the top of the standards must be prominent. I do not intend to think about them for the moment but I like Jason’s suggestion.

Inspection showed that some dimensions are tight, importantly the height of the standards, while others allow quite a lot of room for machining. There are no critical undersize dimensions. However the rear standard is twisted with the bottom of the right leg forward of the left by about 0.030”.

Machining sequence will probably be as follows:
1.   Mount standard outer face downwards on milling table, using shims to account for the twist in necessary, and skim inside edging to provide Datum 2.
2.   Skim rear of base pads and top platform
3.   Face top and bottom of shelf for governor spindle bracket, rocker shaft bearing pads and top of base pads.
4.   Turn over and mount Datum 2 face against table (again using a suitable block of metal) and skim front of base pads and top platform.
5.   On front standard face piston rod bracket bosses.
6.   Clamp both standards together back to back using spacers and super glue if necessary.
7.   Mount vertically with feet upwards on an angle plate. [Think about Datum 3].

This is as far as I have got recording my thoughts. However it has given me the clarity to start work on the standards.


I have made some progress with the pump parts. The pump should be finished next week and I will give details.

I have also made the all important build stand.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #19 on: September 22, 2019, 06:53:53 PM »
It has been a week of puzzlement and progress.

I have decided on the machining sequence for the standards which as follows:
1.   Mount standard outer face downwards on milling table, using shims to account for the twist in necessary, and skim inside edging to provide Datum 2.
2.   Skim rear of base pads and top platform
3.   Turn over and mount Datum 2 face against table (using a suitable block of metal) and skim front of base pads and top platform.
4.   On front standard face piston rod bracket bosses.
5.   Clamp both standards together, front edging to front edging, using some thickness spacers, shims and super glue if necessary. Use two clamps that sit inside the castings. Make sure that the top platform and the inner faces of each standard coincide. Check distance from inside edging to inside edging which should be constant (±0.010”?).
6.   Mount assembly vertically with feet upwards on an angle plate using same thickness spacers and two sets of clamping bolts. Make sure, taking numerous measurements, that the mean line between inner faces is square to the base of the angle plate. This gives Datum 3.
7.   Skim just enough metal off the underside of the feet to give nice flat surface. This is Datum 1.
8.   Skim sides of base pads.
9.   Drill mounting holes in base pads.
10.   Remove from angle plate.
11.   Mount assembly vertically with feet downwards on the angle plate using same thickness spacers and two sets of clamping bolts. Make sure the feet are firmly against the milling table.
12.   Skim the plummer block faces to height.
13.   Drill the holes for the plummer block and governor spindle bracket holes.
14.   Remove from angle block and separate the two standards.
15.   Mount standard outer face downwards on milling table, using shims to account for the twist in necessary [as operation 1] with Datum 1 parallel to the intending cuts.
16.   Face top and bottom of shelf for governor spindle bracket, rocker shaft bearing pads and top of base pads.
17.   Drill and tap stud holes [see below] for the rocker shaft bearing pads.
18.   Finish.
19.   NOTE. The drilling of holes for the piston rod guide bracket will be left for the moment. Likewise the decorative machining.

Geoffrey King used screws and nuts to hold the bearing pads to the standards. I feel it would be nice not the break the cast surfaces of the standards so I intend to use studs.

I hope to start machining the standards this coming week.


I have finished the water pump except for tidying up and polishing. None of the parts present any real problems.

I reduced the size of the spanner hexagon on the screw caps from 2BA to 3BA because it looks nicer. Because they were held by the thread I used an old filing rest that was made many years ago for a smaller lathe. If I tried to produce the flats by milling the cap would have unscrewed from the fixture so scrapping my work. Even so the caps had to be kept in place by a small bar mounted in the tailstock when I did the filing (see attachment).

I do not like turning long small diameter rod so I decided to produce the collars on the pump columns by silver soldering short sleeve over a rod and then turning back the excess metal and solder. The collar/rod gap for the capillary flow of the solder would be fixed by centre punch marks on the rod.  I have this technique very successfully in the past with stainless steel rods and sleeves. It appeared to work this time with mild steel but when I turned off the excess the punch marks were very visible, they had not filled with solder (see attachment). Much puzzlement – I can only think that they too deep for capillary action to work (mild steel being softer than stainless) or the wetting by the solder of the steels is different. The second attempt, this time raising a large, clumsy bur on the ends of the collars worked

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #20 on: September 29, 2019, 06:56:23 PM »
Slow but steady progress has been made.

I am machining the standards in the following stages:
1.   Mount standard outer face downwards on milling table, using shims to account for the twist in necessary, and skim inside edging to provide Datum 2. DONE.
2.   Skim rear of the feet and top platform. DONE – This was interesting since the clamping twisted the legs (see attached sketch) giving an odd rear face of the feet. Not a problem but a warning.
3.   Turnover and mount Datum 2 face against table (using a suitable block of metal) and skim front of base pads, DONE, and top platform, NOT DONE – I decided that this was not required.
4.   On front standard face piston rod bracket bosses. DONE.
5.   NEW STAGE – Front face against the table with suitable packing, correct the rear face of the feet. The finish was not good. The surface was slightly smeared which could suggest a blunt cutter, an end mill.
6.   Clamp both standards together, front edging to front edging, using some thickness spacers, shims and super glue if necessary. Use two clamps that sit inside the castings. Make sure that the top platform and the inner faces of each standard coincide. Check distance from inside edging to inside edging which should be constant (±0.010”?). CHANGE OF PLAN – I could not understand why I was clamping the two standards together. This is typical of carpentry and represents a lack of faith in repeatable machining. It struck me as being very cumbersome with too many clamps. The only possible gain would be the top platform heights might be the same. If you did them individually any difference in height of the crankshaft could be corrected when the plummer blocks were machined.
7.    Mount the standard vertically with feet upwards on an angle plate using same thickness spacers and two sets of clamping bolts. Make sure, taking numerous measurements, that the mean line between inner faces is square to the base of the angle plate. This gives Datum 3.DONE - for the rear standard [the front standard has yet to be machined]. I took the angles of the inner edges to set the datum (see attachment). Since I felt the part seemed very springy the top clamp was as close as possible to the feet.
8.   Skim just enough metal off the underside of the feet to give nice flat surface. This is Datum 1. DONE – Because of the above observations I did this slowly and carefully using a good sharp end mill, lowish cutter speed, low table feed speed and light cuts. It took time but I am happy with the result.
9.   Drill mounting holes in the feet. DONE – The hole in both legs comes out very close to the web of the structure. So more machining and a picture next week
10.   Skim sides of feet. DONE – I could not do the full face because the top of the angle plate was in the way. They will be finished off with a file.

The rear standard has been removed from the angle plate. The front standard and finishing the non-decorative machining on both is the next job. I would like to think that this will be done within the week, but next week is going to be busy.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #21 on: October 06, 2019, 06:05:30 PM »
I have had a busy week outside the workshop.

As for machining the standards, it has been a case of two steps forward and one step back.

I skimmed the feet of both standards flat to give a good Datum 1. After successfully drilling the fixing holes (4BA clearance) in the feet of the rear standard I lost Datum 3 on the front standard. The holes were in the wrong place. I plug them with phosphor-bronze rod held by quick setting epoxy glue and re-drilled the holes. I am not totally happy but I understand why Geoffrey King slotted the mounting bolt holes in the plummer blocks (at least he foresaw the difficulty in keeping a vertical datum through the crankshaft).

The next difficulty became obvious when the holes were drilled. They are far too close to the main web of the casting (see attachment, only one this week); yet more machining. I have abandoned my elaborate work plans since they have served their purpose with the remaining non-ornamental machining operations are relatively simple – facing the top platform, drilling the associated holes and producing clearances and flat surfaces for fixtures. I have started doing the latter on the front standard. The bosses for the piston rod guide bracket will be drilled during assembly.

On Friday I just sat at my bench, looked at these castings and just wondered; would it have been less hassle to have made them from bar stock? If so, would they be carved from a single lump of metal or fabricated?

It is a short write-up this week and next week is likely to be similar. Like anyone who has a good workshop others want to give you work. I only consider neighbours and good friends (family live miles away). A friend’s job has been on the shelf for a couple of months and I cannot ignore it any longer.

AVTUR
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Offline Admiral_dk

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Re: Hick Crank Overhead engine
« Reply #22 on: October 06, 2019, 08:29:00 PM »
Well, progress is progress - even if it is not as fast as we could wish for ....

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #23 on: October 14, 2019, 11:48:39 AM »
A week of progress and I have even done some work on the “foreigner”.

Facing the platform top of each standard and the shelf underneath was simple. The heights of the platform tops from the base are within 0.002” of each other and 0.007” to 0.009” below the drawing. The latter can easily be corrected, if required, when machining the plummer blocks. The holes for the governor spindle bracket, in the shelves were drilled. Geoffrey King used captured screws for the plummer blocks, I do not understand why. Therefore I am replacing them with 8BA studs; their holes were drilled and tapped. On inspection I found that these had half broken through on the underside into the side of the web (see attachment). No problem since I am using studs, but it would make the use of captive screws very difficult.

The webs at the feet have been machined back to give clearance for the 4BA fixing nuts. I can now just about get them in and possibly tighten them. Access for my smallest 4BA spanner is too cramped and the spanner is too long to swing between the two standards (see attachments). There are a number of options:
1.   Carve out more room – I am loathe to do this, everything will just get messier.
2.   Use 4BA nuts with 5BA flats – I know such screws are available but whether nuts are?
3.   Buy another 4BA spanner and modify it – Will probably have to do this anyway.
4.   Use 4BA screws instead of studs and tighten them from the underside of the bedplate. The tapped holes in the bedplate would have to be drilled out – This may present assembly difficulties.

Tomorrow I should finish the non-ornamental machining with the skimming and drilling of the mounting for the rocker spindle bearings. The tolerance on their location is tight so I have produced a simple datum plate that would have bolted onto the feet had the screws not fouled the webs (see attachment).

My shopping list for Friday’s quick visit to the Midlands show is rapidly increasing.

AVTUR
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Offline AOG

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Re: Hick Crank Overhead engine
« Reply #24 on: October 14, 2019, 02:44:26 PM »
If you have a 4BA tap you can make nuts to of what ever size you need. If you don’t have a hex block you can use a pair of full size 4BA nuts to put in the facets or even go with square nuts..

Tony

Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #25 on: October 14, 2019, 03:12:33 PM »
Easiest to drill out and tap some 5BA nuts with a 4BA tap

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #26 on: October 15, 2019, 07:15:24 PM »
Tony and Jason – Many thanks for the suggestions.

I found I had a 4BA – 6BA spanner pressed out of steel plate. Such spanners are just asking to be modified. After quite a bit of careful filing I am now able to tighten all four nuts without having to do further work on the standards. The 6BA end has been cut off so that I can swing it between the standards.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #27 on: October 25, 2019, 01:14:51 PM »
This is really an aside and not a progress report.

Since starting the build of the model I have been trying find out something about the engine and company.

Hemingway Kits give a little bit of information on its web site:
The model is 1/12 scale of a 10NHP engine shown at the Great Exhibition in 1851. The original engine’s cylinder would have had a bore and stroke of 9” and 22.5” with a 90” diameter flywheel.
Hick, Hargreaves & Co. was formed in 1845 when John Hick, who had a foundry in Bolton, went into partnership with William Hargreaves.

Grace’s Guide (summary):
1845 – John Hick went into partnership with William Hargreaves at Bolton
1855 – Stopped build locomotives to concentrate on large marine engines
1866 – Were making engines using the American Corliss valve gear
1868 – John Hick retired
1889 – William Hargreaves died and the business became a limited company
1892 – Became a public limited company. By 1894 they had made over 1,100 Corliss engines of up to 2,000IHP.
1908 – Took out a licence to build Uniflow engines
1911 – Started making diesel engines
1918 – Were making high vacuum condensing plant
After 1945 – Diversified into electrical generation, food processing and oil refining
1968 – Acquired by the Electrical and Industrial Securities Ltd
2002 – Was a part of the BOC Group
The guide has some pictures of large marine and mill engines. Their entries are fully referenced and I intend to take a look at copies of The Engineer at Bristol Reference Library before Christmas.

The works records were deposited with the Bolton Library in 1980 and 1982. Although one of the largest collections they do not feature on the Bolton Library and Archives website (I feel  this says something about our present culture). The collection appears to be indexed at the top level, engine orders, drawings, correspondence etc, but no feature. Like the Bristol Reference Library, the documents are stored off site. I have been in difficult email contact with them for over two months. The archivist, who is part time, has not got a clue what I am looking for and I live 200 miles from Bolton. I think this will require a lot of emails and patience. However, fortunately, the records exist.

A progress report is following in the next few days.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #28 on: October 30, 2019, 08:10:47 PM »
I did not post a progress report last week since very little work was completed. I have now settled in to a work pattern where more than one item is being made (often two at the same time, one in the lathe and the other in the mill). In addition I have had a session of making tooling and fixtures such as filing buttons and a form tool.

The bearing pads on the Standards have been milled flat and the holes for the Rocker Shaft Bearing screws drilled and tapped. I managed to do the holes without breaking through the front skin of the Standards. I also found I had an 8BA bottom tap that actually cut to the bottom of the hole so all four holes now have a thread depth of about 1/8” (I was going to grind the tip of a bottom tap to achieve this but sometime in the dim and distant past... ).
I started on the Rocker Shaft Bearings as if they were glands – Mount a suitable length of bronze rod in the lathe, face end, turn back the diameter (which, if it was a gland, would engage in the cover) and drill and ream the main hole. Transfer to the mill to drill the fixing holes, using the main hole as datum, and shape the flange. Then return it to the lathe to part the item from the rod. Finally file the flange to shape. This was a disaster. First the bronze rod decided to attack the rather blunt lathe tool. After the tool was re-sharpened I made progress although the milling cutter had to fight. Strangely parting off was nice and easy. The bronze has a silvery colour so it could have been aluminium bronze which I have met before. On inspection the part was nothing like the drawing, I had lost control of the hole positions. Thinking about this I realised that on such a bearing the position of the shaft relative to the mounting holes is critical. The general shape is not important. Using a different rod of bronze, a phosphor-bronze I think, two good pads were made. These are now loosely fixed to the Standards with the Rocker Shaft between them.

After the success with the bearings the Footstep Bearing was made. The final filing to shape is awaiting some filing buttons (really waiting for a nice windless day to use the propane torch).

The Governor Spindle and Collar have been produced. The Spindle is a simple length of rod. I decided to increase the diameter of the collar from 3/16” to 1/4” since the 10BA x 1/16” grub screw worried me – 3/64” metal thickness struck me as being too thin. In the end fitting the grub screw was easy although I will have to modify another screw driver.

I am splitting the work into “heavy engineering” and “controls”. I have started on the Plummer Blocks and the Short Rocker which should be the subject of the next progress report. In addition more fixtures and tools will need to be made soon.

Finally my shopping trip to the Midlands show was generally successful except the only 5/16” diameter steel balls (for the governor) I could find were stainless. If anyone knows of a source of mild steel balls please let me know. Otherwise I will have to try drilling stainless balls (stainless may look out of place anyway).

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #29 on: November 19, 2019, 07:13:54 PM »
This should have been posted ten days ago but various things and telephone calls prevented me from doing so before I went on a week’s holiday to the sea-side. To make amends I have attached a holiday postcard (I hope no one will be offended – it has nothing to do with models).

My worries about the stainless steel balls for the governor were groundless. I did what I should have done when I got them home from the Midland show – see if a file cuts one. Yes, it was not too hard. There was then the thought on how you held a ball. Mentally I designed a nice little chuck for the lathe before realising that a ball might be held in a simple collet chuck without it slipping when drilled. Again this worked so a 10BA hole was drilled and tapped in two balls without difficulty. It is nice to have an easy success.

The Small Lever has been finished. The arm and boss were silver soldered together some weeks ago. I took the opportunity to re-drill and face one end of the boss after drilling and tapping the governor balls. The other end of the boss was faced using a mandrel and super-glue to hold the part in the lathe. It was then filed to shape and a tapped hole with a small counter bore drilled in the boss for a 10BA x 1/16” grub screw.

The Plummer Blocks have been made. One casting, rather wide, was supplied which had blow holes in the base surface. The largest was about 1/8” deep. The other block was produced from a cast block of gun metal (I think this was supplied instead of an actual casting). Geoffrey King used square headed 9BA bolts to hold down the Caps. These were trapped by their heads in a groove machined in the base of the blocks. Thinking that this is unnecessarily complex I intend to use 9BA studs Loctited into the blocks. Making the blocks was simple enough but one had to ensure that the blow holes remained hidden and did not break into the side of the block.

I apologise for the heavy shadow on the progress attachment. The photograph was taken in a cold dark workshop.

My trip to the Bristol Reference Library to look at old copies of “The Engineer” was mostly successful. I will post something when I have had a good look at what I copied (the print is very small). I must also have a look at Julius de Waal's design for the engine. Both of these will be left until the next spell of cold weather.

AVTUR
« Last Edit: November 19, 2019, 07:19:16 PM by AVTUR »
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #30 on: December 18, 2019, 07:48:53 PM »
It has been some time since I reported my progress on the model. Cold weather forced me out of the workshop and other persons set my priorities. However I have made some progress.

The Caps for the Plummer Blocks are gunmetal castings, or to be more correct, one casting. This immediately leads to a question: Should I use the casting and try to copy it when machining the second cap or should I make two identical caps and ignore the casting? Thinking I would not be able to produce a good copy the casting I chose the latter option. Two simple caps were made from round bronze bar, what type of bronze I do not know but it was not aluminium bronze. I think I will put slopes on them, like the casting, when it is warmer.

The bearing Brasses were made from bronze bar. The usual way to make these is to solder pairs of partially machined blocks together just as Andy (Chipmaster) on his Stuart Major Beam Engine. My attempts to do this in the past have failed completely, I even considered silver soldering. Thinking about it I decided using a fixture to hold the two halves together was the answer particularly when there are a lot of brasses to make. Before going ahead with the first fixture I had a chat with a former work colleague who makes large model locomotives and such like. He sort of laughed: “As an apprentice, the first day on the shop floor I had to machine and match large bearing brasses. We did not use solder, a ****** large fixture instead.” I made a nice set of fixtures (photograph of one attached) and job became easy – just mount the two halves of the brass in the fixture, put fixture in a lathe collet chuck, drill and ream the bore, face the front face, turn the clamping plate round and face the rear face.

I sat down and started drawing out such a fixture but, since the Brasses were about twice the size of any I had made before, it was quite large – too large to take advantage of a collet chuck. Also was it worth making a fancy fixture for just two sets of Brasses? Previously I had a stupid idea of using the Plummer Block and Cap as the fixture and doing the machining in the milling machine. This had the obvious advantage that the Brasses would match the Blocks and the Caps. I re-visited the idea and decided that if the structure was supported by a plate to take the vertical machining loads while a machine vice clamped everything together it was not stupid. It was also very simple.

During the preparation of the Brasses prior to facing, drilling/reaming and matching I hit a problem – I just could not understand drawing and wasted a day trying to do so. I sat there not understanding what Geoffrey King had drawn and dimensioned. It was a mess unlike his drawings for the smaller sets of brasses. It was nothing like the drawing I would have produced. I then realised that a dimension was missing – problem solved. I puzzled over the mistake and decided he was trying to draw too many parts on one sheet of paper. This seems to be a common failing in model engineering. I was trained to draw one part, however small or large, on one or more sheets of paper with plenty of room. The drawing started with three or more views using the favoured projection. Then additional views, sections, dimensions, notes etc would be added without crowding the drawing. Rant over.

A simple support plate with a hole in it to give a passage for the drills and reamer was made. With the assembly clamped and tapped down on to the plate, and having taken lots of measurements to ensure the bearing hole would be in the centre and of the split of the Brasses, the bearing was drilled, reamed and faced. The drilling was done with increasing diameter steps prior to being machine reamed with an H7 reamer to hopefully give a bore between 0.3125” and 0.3129”. The assembly was turned over, re-clamped and the reverse face faced. Before the assembly was taken apart for marking the entrances to the bore were well chamfered.

After the excitement of the bearings, the Crankshaft (I would call it the main shaft) was easy. The bearing surfaces were done first. A parting off tool was used for the rough machining which was followed up with a freshly sharpened left hand knife for the final cuts. The top slide was set at an angle of 2.5° to facilitate very fine cuts. The shaft was turned round in the collet chuck to cut the surfaces in the reverse direction. The journal adjacent to the crank has an axial float of about 0.002” and a diameter of about 0.3122” (a bit tight, a bit more polishing required). The flywheel journal has an intended generous axial float and a diameter of about 0.3110” (a bit free running, the brasses may need to be closed very slightly). The nose which carries the Crank is a good push fit. The keyways for the Crank and Flywheel have been machined. For good reasons I have not provided a flat for the governor bevel gear grub screw.

I have just started on the Flywheel (diameter 7.5”). An update will follow in a few days.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #31 on: December 30, 2019, 08:01:13 PM »
The Flywheel has been machined and now, or more likely in a few months time, needs finishing with a file. There were no problems but it took a little time, I don’t really like machining cast iron. I had hoped to machine the faces with the wheel in my big four jaw chuck before finishing the rim using the face plate but everything was too large for the lathe gap. Therefore everything was done using the faceplate. I recessed the rim of the wheel which Geoffrey King left as an option. As far as I could see there were three ways doing this:
1.   Mount the wheel on a rotary table and milling out the recesses, one face then remount the wheel to do the other face, with slot cutter – this sort of made sense.
2.   Keep the wheel on the faceplate and drive a square faced tool, like a parting off tool, square in to the face. This is rather like trepanning which I have done on brass plate. I consider this much more frightening than parting off.
3.   Keeping the wheel on the face plate and cutting into the face at an angle of about 20° to the surface with a knife tool, to a depth of about 0.015”. The cut is the opened out using the lathe cross feed, and so on. This takes time and requires left and right hand knife tools but is much easier and gentler than the other methods. I have the time.

I broached the keyway. I had not done such work before and I knew it would be difficult. I ground the end of a short length of square high speed steel to what I thought was a sensible shape and mounted it in a quick change tool holder. By manually advancing the carriage I found I could shave off around 0.001” each in each pass. It took quite some effort, both hands, and however tight I did the nut up the tool post eventually rotated requiring the tool to be reset. I managed to cut a slot 1/32” deep. I feel that this job was at the margin of the lathe’s ability. Both my hands suffered but the arthritis in my left wrist seems to be less now. If I had to broach a number of keyways I think I would make a lever system as shown in Ian Bradley’s book Myford Series 7 Manual.

After all that I made the associated key by filing.

I am now going on to make some of the small governor and control items. Quite a few are fiddly and need to be thought about. So it is going to be a few days producing planning sheets.

The more I think about the Standards the more I believe that they are not fit for purpose. Whether this is my fault I do not know. However I have bought some 5/8” aluminium plate with the idea of machining a pair.

AVTUR

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Offline MJM460

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Re: Hick Crank Overhead engine
« Reply #32 on: December 30, 2019, 08:49:00 PM »
Hi Avtur,

Coming along pretty well.  It is always good to see another update.

I do like that detailing on the flywheel.

What is the problem with the standards?

MJM460

The more I learn, the more I find that I still have to learn!

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #33 on: January 04, 2020, 06:52:22 PM »
Earlier this week I wrote that I was not happy with the Standards. After doing the running trial assembly with the finished crankshaft and bearings I found that the shaft is about 5° to the model centre line. In other words the top of one standard is out by about 0.22”. Not very clever and all my fault.

The two options are:
1.   To try to correct the existing standards. This, I feel, is trying “to make a silk purse out of a sow’s ear”.
2.   Or to make a new set which will take some time but is quite achievable.
In both cases a lot of thought is required.

I do not intend to rush in to this work. I am still writing job sheets for the small parts between migrations to the workshop. I have discovered I need more metal but I do have enough Φ3/32” mild steel rod to make 12BA nuts and bolts!

AVTUR

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Offline Jasonb

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Re: Hick Crank Overhead engine
« Reply #34 on: January 04, 2020, 07:24:45 PM »
You could try some over size holes in the bottoms of the bearing pedestals which may just give you enough movement to swing them into line. Bit more involved would be to solder plugs into a frame sand pedestals then redrill and tap, if you tak ethis option then best to drill it as an assembly rather than individual parts, I did similar with the Allman A frames.


Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #35 on: February 19, 2020, 08:49:36 PM »
I have not posted a progress report for some time. This does not mean I have not been busy. When it has been warm enough I have been in the workshop making governor parts. Most of these are half finished, in most cases waiting for a calm day so that I can silver solder and harden silver steel outdoors. When it has been cold I have been producing lots of planning sheets (wasting a lot of paper and ink).

Making the six (actually seven because I made a spare pair) 12BA Nuts and Bolts was fun! The governor assembly nuts and bolt heads are cylindrical, diameter 3/32”, with a set of flats, 5/64” across the flats, and are mild steel. I started with two sets of taps and dies expecting to break at least one tap. I did a trial manufacture of one bolt without difficulty but ran into a problem with the nut. I just could not drill the hole up the rod for tapping. In the end I used a length of 3/16” diameter bar which was turned down after drilling and tapping. The parting off was done using a cutting disc in a Dremel mounted on the cross slide of the lathe. I had used this arrangement for parting off square headed screws and nuts in the past. I started on the bolts only to have a bolt break off in the die [see the thread I posted last month under “Mistakes, muckups, and dangerous behaviour”]. Still, I had a new second die only to find it had a broken tooth. After ordering two replacement dies I sat down and had a think: Everything would be easier if I cut the heads off 12BA screws, of which I had quite a few, make a second set of nuts and glue them together to make the screws. This was done, using 222 Loctite (I don’t think Loctite grades mean very much with very small screws) and filing the tops flat. The spanner flats were filed using a small piece of hardened gauge plate with a 12BA clearance hole as a stop. The bolts will be filed to length after a trail assembly of the governor. Happy, except that one, the spare, nut has gone walkabout. Now I have to make two nut runners.

Geoffrey King’s drive to the governor spindle was through two bevel gears, the pinion on the crankshaft had 20 teeth and the wheel on the spindle 24. The overall diameter of the pinion was 0.643”. I have only cut simple cycloid clock gears. Small bevel gears are a completely different matter. Looking at various books (Ivan Law’s “Gears and Gear Cutting” and “Gears for Small Mechanisms” by W.O.Davis) it seems that making a good set of bevel gears is possible without hobbing but the whole method/result appeared to me to be a bodge. Anyway I decided that the gears I required were too small for me to make. Fortunately a set of gears, about the right size, were included in the kit. However they
1.   were the same size, a ratio of 1:1 compared with 5:6. This was considered acceptable
2.   had a bore of 3/16”. The diameters of the crankshaft and spindle are 3/8” and 3/32” respectively
3.   The boss diameter was 7/16”, far too close to the crankshaft diameter.
A quick look at the catalogue of a leading supplier showed that bevel gears are expensive and I was unlikely to find a set with a ratio of 5:6. So the supplied gears had to be modified.
1.   A plug would be silver soldered into the bore of the wheel, the plug drilled and reamed to suit the spindle and the dead end of the bore faced to length. The required hole for the 10BA grub screw would be drilled and tapped with a short counter bore to locate the screw during assembly.
2.   A sleeve would be silver soldered over the existing pinion boss to bring its diameter up Geoffrey King’s of 9/16”. Again the boss faced to length and the bore drill out and reamed to suit the crankshaft. Geoffrey King used a key to locate the pinion, however I opted for a grub screw.

I have to admit I was worried that silver soldering might mess-up the gears. Prior to any silver soldering I calculate the amount of solder required for the joint and add on about 25% for the fillets. The solder is then placed so that it finds its own way into the joint during heating. Finally I add a little extra using the rod of solder. I used typewriter correction fluid to keep the solder away from the teeth etc, vulnerable areas received three coats. After running out of Tippex I found that the local supermarket sold Snopake (who buys such stuff these days?) which gave a far thicker coating. I managed to do the soldering, along with some hardening, on what seems to have been the only calm day this year. I was pleasantly surprised with the results. The gears have been finished except for one solder fillet which I will admire for some time before tidying up.

The one other finished part is the Governor Sleeve that did not give any problems. One thing it taught me was that a lot of the small parts can be made from one end of a bar/rod which allows one to have a good holding spigot.

I have started looking at the alternative Standards, more about that later.

AVTUR
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Offline MJM460

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Re: Hick Crank Overhead engine
« Reply #36 on: February 19, 2020, 10:24:56 PM »
Hi Avtur, good to see another update.  Those small parts do take a lot of time to make.

MJM460
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #37 on: April 08, 2020, 01:20:21 PM »
Things have been a little slow on the engine but now that warmer weather has arrived and I am having to discipline my life things might be quicker. The lack of calmed days, I use the propane torch outside, delayed silver soldering and hardening of filing buttons. Whenever a good day arrived it always clashed with a social event.

I have completed the governor parts. The drilling of the Balls and the machining of the fancy 12BA Nuts and Bolts and the Sleeve has already been reported.
 
The Governor Arms required a couple of fixtures to hold them during thinning. I started with 1/8” square mild steel bar over 3” long for each arm. Most of the length was lost during the thinning. First one end was threaded, 10BA, for a short distance, holding the bar in a big four jaw chuck on the lathe. The bar was then thinned to a width of 3/32”, equally on opposite sides (first fixture) and then, likewise, to a thickness of 3/64” (second fixture).  Keeping the arm in the fixture, the two 12BA clearance holes, one for the arm bracket pivot and the other for the link pivot, were drilled through the arm. I got quite concerned that these holes were off centre on the arm until I realised that they are completely hidden by the bracket and link. The arms were then filed to shape.

The Governor Arm Bracket was produced in a similar manner to the sleeve – machined on one end of rectangular 1/2” x 1/4” bar. First a groove was turned to provide area for a small slot cutter to stop or start and the hole for the drive rod drilled and reamed. Then the pivot holes, 12BA, and grub screw hole, 10BA, were drilled and tapped (not quite true; looking at photographs I realise the 12BA holes were done after the slots were cut). The slots for the arms were cut using a 3/64” slitting saw. I have to admit that I do not like slitting saws for many reasons. They seem to be particularly ill suited for vertical milling machines. I ended up holding the bracket in a small precision vice mounted in a larger vice. It seemed rigid enough and the slots were successfully cut. The cheeks of the bracket were rounded with file and buttons before being machined back taking very light cuts with a slot cutter. The part was parted off from the bar and tidied up with a file and buttons.

The Governor Links were made from one length of 1/4” x 1/8” bar. The pivot holes, 12BA, were drilled and tapped along with a hole that formed the fillet radius in the link. The two parts were separated and cut to length. The ends were slotted using the 3/64” slitting saw and the waists were produced and the arms cut back to the fillet using a 1/8” slot cutter. Finally they were finished by file.

The assembly of the governor proved quite fiddly. The clearances on the sleeve had to be increased to get free movement of the links. Other than that there were no problems except that the 12BA bolts and nuts could not be tightened. A special nut runner will be made. The bolts need to be shortened so that their ends are flush with the nuts when tight. After that the bits need polishing.

I am sorry that I do not have any photographs of the finished links and arms. If anyone wants them I am happy the dismantle the assembly and provide them.

I feel that I am making some progress but I am left wondering how Jo can make a model in two or three months.

AVTUR
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Offline Chipmaster

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Re: Hick Crank Overhead engine
« Reply #38 on: April 08, 2020, 01:42:39 PM »
Governors seem to be in vogue at the moment, well done Avtur.

Andy

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #39 on: May 19, 2020, 06:19:57 PM »
At the turn of the year I reported that I was bitterly disappointed with my work on the Standards and considered starting again using aluminium plate. About a month ago I took a good look at the existing Standards and decided to try to correct them:
1.   I corrected my clumsy milling on the feet of the Front Standard by cutting two small blocks of bronze (probably phosphor-bronze) and soldered them in place using high temperature silver solder (740oC to 800oC).
2.   Four bronze plugs were made and silver soldered into the existing 4BA clearance holes in the feet. Low temperature solder (630oC to 660oC) was used. I had some concerns about this operation since I had already plugged these holes in the Front Standard once using bronze plugs and epoxy resin. However it worked.
3.   The bottom and sides of the plinths were milled to shape. I also took the opportunity to increase the cavity in the plinths to ease access for the 4BA nuts.
4.   Now to drill the 4BA holes in the correct place. The plummer block fixing holes at the top of the Standards were correctly positioned so I decided to mimic the main bearings/crankshaft assembly using a bit of aluminium plate. With holes drilled in right places with a datum the Standards could be bolted to plate with their feet in the air. This assembly was mounted in a vice, correctly aligned, the datum found and a small diameter hole, about 1/16”, drilled for the centre of each 4BA hole. I decided that this arrangement was too weak for the drilling of the clearance holes so these were drilled with the Standard clamped onto an angle plate. The whole operation was a success and everything was aligned correctly except for the rocker spindle bearings.
5.   The existing bearing screws, 8BA, needed to be moved. My idea was to fill the holes with low temperature silver solder, re-machine the faces and drill correctly position holes. This was an immediate failure since the molten solder would not fill the holes. The solder just climbed out and flowed away. With the second standard I dropped a short 10BA brass screw into each hole which allowed the solder to plug the hole. The first standard was then plugged in a similar manner. The silver solder was machine back to give a new face and re-positioned holes drilled and tapped.

I am happy with the results, everything is aligned and free.

I have continued making small parts, so another report should follow soon.

AVTUR
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Offline Admiral_dk

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Re: Hick Crank Overhead engine
« Reply #40 on: May 19, 2020, 09:42:08 PM »
It's always nice when you can modify your work result from something you aren't satisfied with to a nice result  :ThumbsUp:   :cheers:

Per

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #41 on: June 07, 2020, 06:58:30 PM »
I have made the final parts of the engine structure, the Bracket, Angle Piece and other bits that locate the top of the governor spindle. Attached is a drawing of the arrangement which has the bracket bolted to the back of the front standard and an angle piece bolted to the back of the rear standard. These are separated by two distance pieces to allow passage of the pump and valve rods from the eccentric. The bracket carries the governor spindle bush. The correct positioning of the bush is achieved with distance pieces between the bracket, angle piece and standards, all held together with 8BA screws.

Geoffrey King’s drawing of the bracket suggests that it is produced from 1/8” thick mild steel plate bent to shape. This is beyond my workshop capability unless I resorted to blacksmithing (more about that in a later blog). My options were either to machine it from solid or fabricate it from three small pieces of 3mm thick plate (I did not have 1/8” plate!). The second option was used. Roughly shaped parts were loosely pinned together with 10BA screws and silver soldered. Milling machine and files were then used to finish. A 1/4” hole for the bush was drilled and reamed. The bush, phosphor-bronze, was made to be a slight interference fit in the bracket.

Obviously the angle piece was to be made from 3/8” x 1/16” thick mild steel angle. I do not have any and a quick search of the usual model engineering metal suppliers suggested they did not either. I dismissed the idea of making it by bending 16 gauge sheet because the finished result might look out of place. So it was back to silver soldering, making it from 1/16” thick strip and a little piece of 3mm plate.

With these changes Geoffrey King’s lengths for the distance pieces were meaningless. These were determined by trial assemblies of the standards bracket parts, the governor and a base jig. The jig replicated the bedplate with the footstep bearing. The adjustments were for the bracket. The spindle passing though the bracket bush had to align with the footstep bearing, cleanly and being able to spin. The bracket needed some aggressive adjustments prior to making the front standard distance pieces. These were made long, the difference in length between the two pieces being important. The rear standard distance pieces were made so that the adjacent hole is the bracket and angle piece lined up. Finally the bridging distance pieces between the bracket and angle piece were made. The back of the rear standard had to be cut back to allow access to the bridge stud nuts (Geoffrey King does point this out in the drawings). Finally the standard distance pieces were shortened by the same the amount to lower the assembly. The aim was to have the spindle bevel gear coming out of mesh when it was sitting on the bracket bush. It would then be put back into mesh by adjusting the spindle collar against the footstep bearing. I hope that all this makes sense.

The work on the brackets went hand in hand with getting the crankshaft aligned. First I had to reduce the front journal diameter get the shaft to run free when assembled in the brasses and plummer blocks. Then it would not rotate when bolted to the engine assembly. Line reaming the brasses made no improvement. In the end I slotted the plummer block fixing holes just as Geoffrey King had done. With the bits assembled including the flywheel the crankshaft and governor spindle train spins easily. The above distance piece and crankshaft work took between 15 and 20 hours

The next stage is to make the eccentric bits and finish the valve mechanism bits. As recorded I have been doing trial assemblies as the model progresses. This has made me realise that the final assembly will be complicated and difficult. There appears to be only one assembly sequence and access to small nuts and hexagonal headed screws is fiddly. So far I have been using cheese head screws in the trials in the belief that they are easier to handle. I need to start a first attempt at assembly instructions soon.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #42 on: July 13, 2020, 01:08:06 PM »
I have completed the first half of the valve mechanism. The arrangement is different, to say the least. The eccentric, on the crankshaft, is conventional but its strap is held by the water pump plunger, not the valve rod. The motion to the valve is transmitted through a number of links and a rocker shaft. There is nothing like a Stephenson’s motion, the engine ran in one direction and if there was a variable cut-off it is not modelled. The engine can be stopped by disengaging the Valve rod, hanging from the eccentric strap, from the rest of the mechanism by using the Gab handle [see attached annotated picture].

The Eccentric strap was made before the Eccentric. There was nothing difficult or unusual about making it. I did worry that the bore, as cast, was large and may give problems when the strap was bored out after it was split. Likewise the Eccentric was easy with the crossing out taking most of the time. I only use metals of known providence, I do not raid scrap yards or scrap bins, and try my best not to mixing my stock. I chose a nice, short piece of mild steel bar for the eccentric and started to turn it. It cut beautifully with a very fine finish, far better than ordinary mild steel. I then realised I had bought about 6 inches of EN24T bar with a similar diameter to make a short crankshaft for an IC engine many years ago. I guess that the off-cut was put in the mild steel box.

The Short and Long rockers were fabricated, round bar for the boss and rectangular strip for the arm. The Short rocker was made in October as a trial which worked. The bar was drilled from both ends, a shallow hole to act as a datum for milling operations and a deep hole over half the length of the bar. A slot was cut to half the diameter of the bar, into the long hole, for the arm. The long hole was stuffed with short bits of silver solder and flux and heated. The Long rocker was made in a similar manner but the soldering was done after turning the handle and thinning the arm. The end of the handle was turned with a little form tool. A hole that matched the handle diameter was drill in a small piece of gauge plate and the surplus metal removed using a hacksaw leaving a nice little inside radius. The plate was hardened and tempered and the top surface ground to give a cutting edge. It worked. The strip, square, was clamped to a simple fixture, just a trough cut in a small piece of aluminium plate, and thinned using a slot cutter. No comment is needed about the Stud carried by the Long rocker.

Making the Valve rod was simple with the shafted being thinned to 3/32” by 1/8” from 1/4” square strip in the same way as the Long rocker.

The Gab end handle was produced in the same way as the Long rocker handle. It was then bent by heating to red heat, slipping a tube over the handle while holding it in pliers. By the time it came to bending, about three seconds after removing the flame, it was no longer red hot. However it worked and looks neat enough. The rest of the work was milling, drilling and filing. However I did manage to break a 3/32” slot cutter when cutting the slot for the Stud which meant a lot of delicate filing of the slot to get it to fit snugly.

As drawn the Pump rod was rectangular strip, 3/32” x 5/32”, nearly 5” long with additional 8BA threads at each end. I did not have enough 3/32” thick strip and, quickly looking on the internet, nobody could sell me any. I thought about using 5/32” diameter rod but chose to try to follow Geoffery King. I managed to thin down 7” of 1/8” x 1/4” strip to 3/32” x 3/16” and decided that would do. The resulting strip was nicely bowed (one side now not having any residual stress). The bow was quickly removed using a 4” vice and four 1/4” BSF bolts that had shanks (not threaded up to the bolt end) as a four point bender. The underside of the bolt heads were super-glue to the top of the vice faces so that the two central bolts were about 2 1/2” apart. The straightening operation worked like a dream taking less than two minutes compared with fifteen setting up and over sixty thinking about it. There is a just perceivable bend in the other plane which I have left. The lathe with a nice big four jaw chuck was used to produce the 8BA ends.

The next job is the cylinder. I have had a long hard think about the machining operations and will start in about a week’s time. Before then I must clear-up the workshop. It has become a tip with too much kitchen and motorcycle junk.

I have a possible question: Sometime soon I must consider the fixings (nuts and bolts). Like Geoffery King I will use hexagonal headed bolts/screws. He seems to have made his own but I have bought them off the shelf and will shorten them, as required, using a lantern chuck. He did not use washers. Looking at drawings and pictures of Hick & Hargreaves of the period they certainly used washers. It is my intention to fit a washer under any nut that does not lock the thread.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #43 on: October 10, 2020, 05:22:40 PM »
It has been three months since I last written a progress report. I have managed to get all the kitchen junk and most of the motorcycle spares out of the workshop. I took a lot of workshop rubbish to the local tip (re-cycling centre). I even made a bat box. Also I sold the Kawasaki.

I took a long hard look at the Cylinder casting and realised that none of the major casting faces should be used as datums. Obviously the final datum is the centre line of the cylinder bore which has to be square to the Bedplate. The valve face should be parallel to the centre line and midway between the front Standard. It follows that the most important face is the underside of the mounting flange (Face D in the first attachment). However this can only be machined with the cylinder rotating horizontally on a mandrel between a rotary table and centre. Therefore the casting had to be prepared for drilling with an under size bore to take the mandrel.

First Faces I & J and Edges A & B were filed clean and square so that the valve face, Face G, could be machined smooth BUT not back to the final dimension. When mounted in the machine vice there was a considerable slope on the face which was fly cut (a tool I don’t really like) flat. The casting then clamped to the lathe cross slide and the ends skimmed with the fly cutter so that they were square to Faces G, E & F. The optimum position on each end for the bore centre line was then marked out using a surface table and very nice second hand height gauge. The casting was put back on the cross slide and height set using an alignment microscope in the headstock spindle. A ϕ7/16” hole was drilled part way up the cylinder from its bottom, dead, end (Face H). This was repeated with a smaller hole from the top end to meet the existing hole (I have a mistrust of drilling long holes in bronze). Once happy I drilled to the depth of the bore, 2 1/2” with a ϕ1/2” drill.

Feeling pleased with myself I made a between centres boring bar and tried taking the bore out to ϕ5/8” Complete failure, the tool would not cut and the bar was far too flexible. At this point I did look at a Keats plate but in times of desperation one reaches for the big four jaw chuck. Taking great care with mounting the cylinder in the chuck I managed to reach ϕ5/8”. I also managed to bore all the way through the cylinder, a really sensible mistake (and I mean it).

A stepped mandrel was machined from a ϕ1” steel bar (see attachment) with a ϕ5/8” section that was location/clearance fit with the bore. A 3/8”BSF nut forced the cylinder tight against the step. This was mounted between the rotary table and centre on the milling machine table. Edges A & B and Faces E & F and I & J were machined to size. The circular edges of the flanges and cylinder body were milled every 10° to gives surfaces that were later filed smooth. The mounting flange faces and the underside of the cover flange were then machined. The latter is important since the gap between the flanges has to be large enough for the fitting of the cover screws.

The assembly was then held vertically in the machine vice and the underside of the mounting flange spotted, using a ϕ4mm x 100mm centre drill, prior to drilling the holes for the Bedplate studs. The holes were then drilled using a similar long drill. I discovered that I had drilled 6BA clearance holes instead of 8BA holes. A lot of thinking, in the end I decided to use 8BA studs each with a ϕ2,8mm collar (more about that later).

The cylinder was removed from the mandrel. A bronze stepped sleeve was turned up and silver soldered in place at the bottom of the cylinder. The hole was then tapped to 1/2” x 26t.p.i. (Whit) to give a nice boss. One mistake rectified. It was then returned to the four jaw chuck and the top of the cover flange, Face C, faced back to give the required flange thickness.

The face for the valve portface block, Face G, was milled back to the correct distance to centre line and the two steam passages were cut. Great care was taken with the six 8BA tapped holes for the portface block screws since they end very close to the cylinder wall. This scared me so I left the bore at ϕ5/8” in case of problems. Luckily there were none and I can take to bore out further, to a maximum of ϕ3/4”. Fortunate since there is a small defect (blow hole?) on the surface of the bore.

Finally the four bolt holes and the two stud holes were drilled for the cover bolts. The bolts and studs are 10BA and I inadvertently drilled the stud holes for tapping at 10BA clearance. Fortunately there is sufficient metal present to tap them to 8BA and use stepped studs.

During this work I found two errors on Geoffery King’s drawing:
1.   The radius of the mounting flange is given as 3/8” when it should be 3/4”. Obvious.
2.   The distance between the top two sets of tapped holes for the portface block screws is given as 1 5/8” when it is 1 3/8” on the block. This could give you trouble.

The final boring and lapping will be done some time in the future.

I finished this work over a month ago and have make studs, quite a few studs, and the machined the bodies of the valve since. This will be written up next time it rains.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #44 on: November 30, 2020, 02:46:58 PM »
Since my last report it has rained but remained warm. Therefore I have been working away in my poorly heated workshop and not reporting on my work. I am now making full use of a cold spell to catch up on non-workshop work.

The Portface block and Valve chest are cast iron castings which makes a change from gunmetal (or whatever you like to call bronze). In both cases the iron machined easily, there were no hard spots or holes and the skin presented no problems. There was excess iron on the Valve chest where the mould had collapsed slightly. This worried me until I started to machine it.

The Portface block overcomes the problem of the steam passages between the valve face and cylinder. The outer ports connect with passage slots cut in the side face of the cylinder that transfer the steam to either end of the cylinder. The exhaust steam from the centre port passes through two slots to the exhaust manifold. The Portface block is attached to the cylinder by six short 8BA countersunk screws until the final assemble when it will be glued in place in addition to the screws. I have no idea what glue Geoffery King would have used in 1956. (K N Harris in “Model Stationary and Marine Steam Engines” suggests a mixture of litharge and glycerine. Litharge is lead monoxide, not easy to obtain I guess). I will use a thin film of good epoxy resin.

The Portface block casting required quite a bit of machining on the two major faces to bring it to drawing dimensions The only thing I messed up on was the steam inlet ports, I misread the drawing (Geoffery King’s drawing practise would not have been acceptable at the apprentice training school) and drilled a ϕ1/16” hole centred on the outside edge of each port instead of the centre. The hole was to give relief for the ϕ1/16” slot cutter used. Fortunately the holes were drilled at the end of an afternoon shift and the mistake discovered next day. After a quick think I filled the ports with J B Weld, drilled the relief holes at the ends of the slots, the correct positions. I then did a lot more thinking, drawing and doing sums only to find that Geoffery King had been very generous with valve lap, even with my little mistake the valve shoe closed the inlet passages for quite some distance either side of the end travel. The slots were cut from both sides since their length was 11/32”. I have not bothered to square the ends since the engine will never be required to deliver a lot of power. One or two of the holes for the fixing screws just broke into the exhaust slot side wall. This is of no concern since the block will be glued in place. The only other difficulty I had was countersinking the top screw holes, I needed a ϕ3/16” diameter countersink. Fortunately there are companies out there that will supply one by post within 24 hours.

The Valve chest presented no real problems. The casting flash was removed with ease using an end mill. The cavity was cut out using a slot cutter followed by an end mill to square the corners at the steam inlet end. The two corners between three sides remained a bit of a mess but they do not interfere with the valve shoe.
There was no casting for the Valve chest cover so it was machined from a short length of ϕ1 3/8” cast iron (Meehanite?) bar without any problems. Likewise the Gland was produced from phosphor-bronze bar.

Up until now I had been using any available cheesed head screws for ongoing trial assemblies so I took the opportunity to make studs from steel BA screws (of which I seem to have plenty). The ends were cut to length as I had done with the 12BA screws [The screw was held, locked in place with a nut, in a short length of tapped brass bar mounted in the lathe using a collet chuck. It was then parted of using a small abrasive disk in a Dremel mounted in the tools post (attached is a photograph I have shown earlier)] and the cut end chamfered. However simple this sounds it took time particularly with 8 and 10BA screws (if one drops on the floor don’t bother looking for it). While writing about studs, six sleeved studs 8BA were made for the cylinder mounding flange. A short length of ϕ1/8” steel rod was tapped with an 8BA thread and cut in to 1/16” lengths. Again the Dremel was used in the lathe. One each was loctited to an 8BA screw and turned to the required diameter. The stud was then produced from the screw as above.

As mentioned earlier I have been doing trial assemblies as the model progresses. The cylinder and valve assembly was more than a tight fit in the bedplate and between the standard feet so quite a bit of filing had to be done.

I have yet to photograph the finished valve chest parts and the assembly with the cylinder. These will follow soon.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #45 on: December 12, 2020, 05:05:24 PM »
I promised about a week ago that I would attach photographs of the Portface block and Valve chest. These are attached.

The studs are loose in the castings. They will be Loctited on final assembly. I tried locking them in place using shellac varnish with the idea that they would be easy to unlock (either by heat or soaking in methylated spirits). This did not really work. While the idea was sensible it was messy and took a long time to “cure”.

I have now returned to making the little fiddly bits.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #46 on: January 21, 2021, 12:50:18 PM »
This is not really a progress report, more of a celebration.

Very little work has been done since my last posting. I spent the days before Christmas wrecking a corner of the workshop to provide space for the new lathe. After that the cold has only allowed me to use the place three times. I am still making fiddly little pieces about which I will report in a few weeks time.

In one of my early blogs on this engine I mentioned my concern about cutting 3/64” wide slots. After advice and postings on this forum I found a firm in Surrey that supply a vast range of cutters mainly to industry. I bought three HSS slot cutters over the internet and they arrived next day. Yesterday I cut my first 3/64” slot, 3/16” long through 1/16” thick mild steel. And I did not break the cutter.

 :) :) :wine1:

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #47 on: July 06, 2021, 05:46:27 PM »
I have not posted a progress report for quite some time. For the early part of the year my workshop life has been dominated by the cold weather and having to build a bench for my new lathe. I got back to the model by Easter after the new lathe was installed and continued to make small and complicated items.

Early May I returned to the Cylinder to bore it out to ϕ3/4”. Back in October I reported that a casting defect could be seen after the Cylinder had been bored out to ϕ5/8”. The Cylinder was once again set up in the Keats plate and bored out to ϕ3/4”. On inspection the casting defect had become a 1/8” blow hole with some evidence that it almost reached the outside surface (see attached photographs). Thinking, I decided I had the following options:
1.   Nothing. It is only a model and should still look pretty when finished. It may not work at all and the piston ring, if an O ring or graphited string, would be destroyed if run.
2.   Try filling with epoxy resin or soft solder. Access is difficult particularly for cleaning before and after filling the defect.
3.   Sleeve the bore. The sleeve would have to be thin, about 0.040” thick, and prevented from rotating (shrink fit?).
4.   Drill through the wall at the defect and silver solder in a bronze plug. Sounds radical but I think this would have been the best option before final machining.
5.   Get another casting. If one was available there would still be quality concerns.
6.   Machine a new cylinder from bronze bar (or cast iron?). This would take some time machining to shape.
I put these options to a meeting of the local model engineering society where it was suggested to sleeve the bore, doing the final boring with the part machined sleeve in place in the cylinder.

I decided I had enough room to take the bore to ϕ13/16” to take the sleeve. The minimum thickness of metal to the steam passage and tapped holes would be between 1/16” and 3/32”. I bought a reamer for the job and made plug gauges to guide me.  Back to the Keats plate and using a ϕ3/4” bright steel bar I set the cylinder up to run true (I was now getting quite good at this). I bored and reamed the cylinder out to ϕ13/16”. A 4” length of ϕ1” Colphos 90 bar was turned down to 0.004” below ϕ13/16” (a 0,05mm being the optimum for the Loctite used) and bored out to ϕ5/8”. I have always had problems with drills wandering off the drilling line when drilling deep holes in bronze. Someone at the society said he drilled holes in bronze at high speed. I tried it (about 500rpm for a ϕ1/2” hole) and it worked, no problems. After cleaning and using an activator (Loctite 7063) I glued the sleeve into the cylinder using Loctite 638 (high strength retaining compound) and left the assembly to cure for most of a week.

The Cylinder was returned to the Keats plate and the assembly bored out to ϕ11/16” (just over). I felt that I should not push my luck by going “the whole hog” to ϕ3/4”. The surface finish was good and the bore parallel so a reamer was not used for the final cut (I have found that a new reamer in bronze scores the bore and I did not fancy sitting down and stoning the rakes off the end of a reamer). The bore was honed using a wooden laps and x600 grit (the finest I have). Finally the steam passages were re-drilled.

I now have a good cylinder. I am rather impressed with the Loctite.

I have not included the usual progress photograph since the model is dismantled.

I have made the piston, piston rod and cylinder cover. These will be the subject of my next report (soon, I promise).

AVTUR
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Offline Admiral_dk

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Re: Hick Crank Overhead engine
« Reply #48 on: July 06, 2021, 07:55:38 PM »
Good news that you got it saved and can continue with the build  :cheers:

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #49 on: July 18, 2021, 05:27:59 PM »
Very early on in the model build I had a think about the Piston Rod. It is about 5 1/2” long with a step from ϕ3/16” to ϕ5/32” about half way along. Although I have done it I do not like turning down long lengths of small diameter rod so I sought an alternative way to produce the piston rod. I decided to do a trial at silver soldering two rods together. Holding the larger rod in a collet chuck I drilled a hole up the centre, about 0.008” larger than the diameter of the small rod for about 1/2”. Flux, as a dry powder, and small chips of solder were loaded into the hole and capped by the small rod. A fire brick was placed on each rod and heat applied. Even with the bricks the rods had to be carefully pushed together. It worked remarkably well.

A year later I decided to finish the rod only to find I had used ϕ5mm and ϕ4mm rod. The process was successfully repeated with ϕ3/16” to ϕ5/32”mild steel rod. The result was not quite straight and proved very difficult to correct using a simple three point bender. I did the best I could and decided it did not matter. Looking at it a couple of months later, when finished, I think I did pretty well.

The ends of the rod were simple to finish but a 3/64” wide slot was required in the ϕ3/16”rod just above the join. This locates the Crosshead (which will be described in the next report) using a cotter pin and pad. The crosshead, part made, had a long body with a 6BA hole away from the slots to clamp the rod using a brass screw. A similar arrangement using a square bar was used to keep the alignment after the crosshead was removed. Prior to cutting the slot the crosshead was assembled on to the rod and clamped. The second bar was also clamped, square to the intended slot on the larger diameter part of the rod. Two ϕ1,1mm holes were drilled with great care across the crosshead and rod. The cross head was removed, the rod returned to the milling machine and the slot cut between the holes. The ends of the slot were filed square (sort off) with a needle file.

The cylinder cover and gland were made without problem. The cover was a casting with a spigot which was only there to hold it during the early machining operations. I have one comment on my machining; I tend to keep to tight tolerances which leads to some filing when fitting. The Piston was made from good cast iron and presented no problems. The final turning of its outside diameter was done on the piston rod held in the collet chuck. The clearance is about 0.004”.

I was concerned about the lack of room to fit the cylinder cover screws. The four of them would be too long to be fitted head down between the two flanges. After some thought I decide to make studs of the correct length, Loctite the top nut in the correct place and pretend that the nut below the flange was the screw head. On doing the trial I found that could fit the screws with the correct length (lucky the holes were slightly over size).

More to come. I am beginning to think that the end is in sight so what am I going to build next? I fancy designing my own engine (I have started designing engines in the past only to find they were getting too complex).

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #50 on: November 27, 2021, 04:00:56 PM »
It is over four months since I posted an update. This one covers the crosshead and connecting rod.

The Crosshead was started months ago as part of a silver soldering session. About 1 1/2” long length of mild steel 3/8” square bar was cross-drilled towards one end and a similar length of ϕ3/16” mild steel bar silver soldered in place. The piston end face was faced and the rod hole was drilled and reamed. The square bar was turned to a diameter for about 1/16” from the face and the hole well chamfered, at 45°, to butt on the shoulder of the piston rod. After the cross drilling of the crosshead and the Piston Rod, in situ, the rod was removed and the slot for the cotter pin and pad finished. The part was mounted in the four jaw chuck and the trunnions machined. The dead end with the tapped hole to take the clamping screw (described previously) was cut off and the part glued to a short length of ϕ5/32 mild steel rod. The top, crank end, of the crosshead was then carefully faced to length. The rod was then removed by a sharp, light, tap with a hammer and the crosshead re-glued to turn the final chamfer.

I did a lot of thinking about how to make the Connecting Rod which is forked and looks very flexible (I attach the drawing of the part). Prior to starting I solid modelled a number of machining options.

Two ϕ10mm holes were drilled at the ends of a 4” length of 1 3/4” x 3/8” mild steel plate for bolting the plate directly on to the milling machine table. In addition two ϕ3mm datum holes were drilled so that the part could be quickly re-positioned after being moved. With the plate sitting on a similar aluminium plate the “top” surfaces of the connecting rod were machined with a slot drill. The rod was the removed and the aluminium plate machined to give a mirror surface so that rod had a good base to sit upon. The rod was turned over, sat on the aluminium plate and the “bottom” machined in the similar manner.

ϕ3mm holes were drilled at every internal corner and at the ends of cutter runs. Prior to cutting the part out with a ϕ3mm slot drill end holes for the cotter pin and pad slots (two 3/64” wide and one 1/16” wide) were drilled. These slots were then cut to just over half depth followed by the edges, again to just over half depth. The part was turned over and the slots and edges cut through. I now had successfully produced the rod without breaking any small drills. Because it was thin and forked I decided it could easily be damaged. Therefore, before any further work, two small brass blocks were glued in the fork (these have been removed a number of times, just rest a long face on a flat metal block and give the brass a sharp tap). An attachment shows the connecting rod after tidying using a selection of small files.

The progress on the model is way ahead of this blog. Since the weather is too cold for the workshop the next posting could be quite soon.

AVTUR
There is no such thing as a stupid question.

Offline Jo

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Re: Hick Crank Overhead engine
« Reply #51 on: November 27, 2021, 04:37:23 PM »
Well done. You have made a good job of that connecting rod  8)

Jo
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Offline Admiral_dk

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Re: Hick Crank Overhead engine
« Reply #52 on: November 27, 2021, 08:05:12 PM »
That is a rather complex shape for 'a simple conrod'  :o - but very nice result, that you can be happy about  :cheers:

Per

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #53 on: November 28, 2021, 12:05:46 PM »
That is a rather complex shape for 'a simple conrod'  :o - but very nice result, that you can be happy about  :cheers:

Per

Per

Everything about the engine is complex.

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #54 on: December 22, 2021, 02:59:25 PM »
Autumn has come and gone. During that time I have been occupied making and trying to fit small fiddly bits.

The connecting rod has two little end bushes (Geoffery King calls them brasses, a name I have not seen before and not quite in my Collins English Dictionary) and a single big end bush. Each is held in place by a strap with a cotter pin and pad.

The straps were produced from rectangular bar with the outside dimensions matching the width and thickness of the strap. I cut the bar to a length far longer than required for one strap and the drill the ends of the eventual slot to easy slot cutter access and to locate to filing buttons. The buttons were used to facilitate the shaping of the end with a file. The two small straps have rounded end while the large, big end, strap includes a boss for an oil hole. I did not make too much of a mess of this filing exercise. After the slot that holds the bush was cut the slots in the sides for the cotter pin and pad were produce using a slot cutter cutting from pre-drilled holes. The cotter slots on the small straps are 3/64” wide while those on the larger strap are a 1/16”. The ends were filed squarish with a modified needle file. I discovered that I could buy a 1mm across the faces file that only cut on the edge. I bought two knowing that one edge would have to be ground back to get into the slot. In the end I also had the grind back one of the faces. The surplus end of the part was then removed with care using a slitting saw. And I have yet to break a 3/64” slot drill.

I have made cotter pins and pads before. Then there were ten sets required so I cut a length of rectangular bar on the milling machine with the head set at a slight angle to give the correct profile and then sliced the bar like bacon using a slitting saw. While this worked the control of the cotter angle was poor and I felt I could do better. A short strip of 1/2” plate had the profile of the seat of the pad cut in one end and the other left square. Slots were then cut with a slitting saw on both ends so the remaining strips of metal were the correct thickness, 3/64” and 1/16”, for the cotters. The plate was transferred to a vertical slide set at 7° mounted on the lathe cross slide and the pins and pads cut off with a slitting saw. Sharp edges were then removed with a small file.

The production of the 3/64” thick cotter pin and pad for the crosshead was included in this work. Geoffery King only used a pin in his design but I opted for a pin and pad.

I have more photographs covering the making of the cotters and bushes than allowed for a single posting. Therefore details for the bushes will follow shortly.

AVTUR
There is no such thing as a stupid question.

Online Kim

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Re: Hick Crank Overhead engine
« Reply #55 on: December 22, 2021, 03:21:28 PM »
Neat! That's a pretty ingenious way to make the slope on the cotter pins.  I like that!
Kim

Offline Jo

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Re: Hick Crank Overhead engine
« Reply #56 on: December 22, 2021, 04:27:51 PM »
That looks good  :) ... I hope the red stuff on it is not blood  :paranoia:

I also call that type of bearings Brasses.


Jo

P.S  If you need to cut a thinner slot than you feel safe doing with a slot drill type milling cutter I found using a thin wood rough cutter from either side and joining with a needle file worked  ;)
Enjoyment is more important than achievement.

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #57 on: December 22, 2021, 04:38:50 PM »
That looks good  :) ... I hope the red stuff on it is not blood  :paranoia:

I also call that type of bearings Brasses.


Jo

P.S  If you need to cut a thinner slot than you feel safe doing with a slot drill type milling cutter I found using a thin wood rough cutter from either side and joining with a needle file worked  ;)
With my present skills I am happy to try to cut narrower slots with a slot drill, until I start breaking cutters. I treat such items as disposables.

I will explain the "blood" in the next posting.

AVTUR
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Offline propforward

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Re: Hick Crank Overhead engine
« Reply #58 on: December 23, 2021, 01:36:38 AM »
It’s a fascinating build - I really enjoyed reading it. Some trials along the way but the engine looks marvellous.
Stuart

Forging ahead regardless.

Offline steam guy willy

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Re: Hick Crank Overhead engine
« Reply #59 on: December 23, 2021, 01:59:00 AM »
Looking good and I see the drawings are in fractional Inches.  I think they were used before digital  became popular and was approached by using sharp pointed dividers with a deeply etched steel rule.! I do have a modern digital veneer that has fractions as well as metric and imperial scales ??!

Willy

Offline ettingtonliam

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Re: Hick Crank Overhead engine
« Reply #60 on: December 23, 2021, 02:22:57 AM »
Yes, split bearings were commonly called 'brasses, and your 'cotter pads' were 'gibs', the whole being known as a gib and cotter joint.

Having gone through the process 16 times for the coupling rods and connecting rods for my 7 1/4" gauge Locomotion model, I wish I'd seen your system first!

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #61 on: December 23, 2021, 12:09:42 PM »
The major problem I had with the cotters was collecting them after the final cut with the slitting saw. Sometimes they just sat in the gap or on the cross slide. Other times I had to search the tray under the lathe. It is always wise to clean out the tray before doing such work!

AVTUR
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Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #62 on: December 23, 2021, 04:06:02 PM »
I am going to try to get this on to the forum site before Christmas!

The connecting rod bushes, brasses, although very much smaller, were be produced in the same way as I had planned to make the crankshaft bushes two years ago. And I had similar problems. They were made from COLPHOS 90 bar. For the halves that sit against connecting rod the bar was milled to a rectangle twice the height of the half, hole drilled under size and the sides slotted to take the strap and connecting rod. The result was the halved by milling away the surplus on the strap sides. The halves that were held by the strap were just turned, the centre with a parting off tool, drilled with same size drill and halved as above. So far so good.

Fixtures were made to hold the mating bushes so that they could be reamed to size (which would have been a mistake) and faced to length. The thickness of the metal at the end faces is small. On the two smaller bushes it is 1/64” and the fixture did not give adequate support. Another set of bushes were made and this time they would by faced to length and bored to size when assembled on the connecting rod.

Getting the lot to fit took time. A lot of small fine filing work was done on the end of the connecting rod, the straps and to the cotters. I guess it would have been easier to work to looser tolerances but... In the end the pads would fit the straps if the straps were just squeezed slightly by finger pressure. The bushes, assembled, were then filed to length and the bores opened up to suit the trunnions on the crosshead and crank pin using a clockmaker’s broach. This allowed the small end bushes to be line “reamed” (sort of).

Obvious there is no interchangeability of parts so all the bits had to be matched. I generally used small centre punch marks to match parts but this is out of the question with the bushes so each bit of the assembly is painted with different coloured permanent marker (hence the blood on the assembly). Trouble with this is that the dried ink easily rubs off so the marking is repeated after every assembly. All this work was done in a large document box lid since I would never find anything that fell off the bench.

The crank web and pin were made without difficulty. Once again the pin’s bearing surface had to be produced used a parting off tool. The broaching of the web keyway was easy and the web fits snugly on the shaft with its key.

At this point problems return. More should follow before the New Year.

Happy Christmas

AVTUR
There is no such thing as a stupid question.

Offline AVTUR

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Re: Hick Crank Overhead engine
« Reply #63 on: September 02, 2022, 04:21:05 PM »
This is just a short posting.

I am still working on the model which is nearly finished. However progress has been slow because the real world is making demands on my time. I have also been side-tracked by starting another model.

A proper progress report should be posted during the autumn (fall).

AVTUR
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Offline Admiral_dk

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Re: Hick Crank Overhead engine
« Reply #64 on: September 02, 2022, 08:11:16 PM »
Good to hear that you still are around  :cheers:

Per

Offline GWRdriver

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Re: Hick Crank Overhead engine
« Reply #65 on: September 04, 2022, 04:52:12 PM »
Excellent work and very informative.