Author Topic: B Hick & Son 1851 Oscillating Engine  (Read 3252 times)

Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #15 on: February 02, 2020, 04:18:47 PM »
The cylinder is a tricky casting as both the bore and the pivot must be at exactly 90 degrees to each other. There is two options to machine this: do the pivot faces first or the cylinder bore faces. I chose to do the cylinder bore as the pivot faces are measured from its centre line.

I cleaned up one end of the cylinder and found I could accurately hold it to turn and face the other end and both pivot faces were square to the bore  :) The first end was turned to 25.4mm and faced. This was then used to hold the cylinder to take the other end down to 25.4mm and face it before boring through at 11.1mm. This end is now the top of the cylinder.

Using a mandrel in the bore of the cylinder the cylinder was taken to its correct length. And the inner faces of the ends were carefully hand "shaped" by using a parting off tool in the tool post and pulling the spindle round (the steam ways mean you can only go part way round the cylinder  ;) )

The cylinder now fits in the gap on the base casting  :wine1:

Jo



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Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #16 on: February 04, 2020, 03:58:29 PM »
Having marked the centre line between the two cylinder flanges the final two parts could be turned. First up is the simple parallel end turned by holding the part in a four jaw chuck. The casting was centred by using the two jaw slots in the face of the chuck and the marked line on the end of the spigot used to centred on the tailstock (a quick check down the lathe nose confirmed that the other end of the casting was about central as it went round  :) ).

This turned surface was then be used in a 6.35mm collet to hold the casting, with tailstock support, while first the flange then the bearing surface was turned down.

The cylinder now fits even lower in the base than it did before. I really need to make the two remaining bearing blocks  :thinking: but there is still another casting left.

Jo
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Offline bent

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #17 on: February 04, 2020, 06:40:41 PM »
Presumably the pivot bearings will lift the cylinder up enough to allow the bottom to swing freely.  But how is sealing maintained on the valving cross piece, is there a spring in there somewhere?

Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #18 on: February 05, 2020, 07:42:00 AM »
Yes there is a spring that provides the seal for the valve plate.

Jo
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Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #19 on: February 06, 2020, 04:30:06 PM »
The cylinder covers and gland are a simple turning job. What is more interesting is drilling the cylinder for the covers, the steam ports and the cross drilling down from the cylinder ends. I started with the covers drilling them 2.3mm for 8BA clear. I then drilled the cylinder ends for 8BA tapping so that I could check alignment (these will later be opened out and reverse bolts fitted  ::) ) I also took a little off the inner face to improve the steam flow around the inlet area.

The Steam inlet to the cylinder was cut using a 4.76mm slot drill and then a 2.2mm hole drilled 15mm deep. On turning the cylinder round to cut the oscillating face another two 2.2mm holes were drilled and I was pleased to find they met the original pair of holes  :wine1: However not everything goes right I thought I would be clever and drill the centre pivot hole a little deeper only to find I broke off the drill  :toilet_claw: After a bit of poking around with a needle I decided to try the put the cylinder in some light oil in the ultra sonic cleaner and see what that might do. I am pleased to say the drill end came out  :)

Last bit to show you for today: the piston gland has to be drilled for 10BA studs, three of them (Zee you will recall your question on this ;) ) to prevent drilling into the collet I put a washer under the face while I was drilling and while the washer was damaged the collet was not. I don't think I can put off making those bearing blocks for much longer  :Lol:

Jo
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Offline gbritnell

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #20 on: February 06, 2020, 04:39:22 PM »
Very nice work!
gbritnell
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Offline Jasonb

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #21 on: February 06, 2020, 05:04:18 PM »
Looking good and a lucky save with the broken drill. Do you think you will need to take a bit off the cylinder OD to get the bolt heads in as some of those holes look quite close?

Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #22 on: February 06, 2020, 05:14:17 PM »
Thankyou George  :)

JB: It is always necessary to fit bolts when they go tight against the cylinder, it should require only a flat on the bolt head but in one position the cylinder will need cleaning up with a milling cutter.

Jo
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Offline Jasonb

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #23 on: February 06, 2020, 05:28:09 PM »
Yes looks like one side of the square headed bolt will need to be filed almost flush with the shank. Are you going to add the fat pot too?

Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #24 on: February 13, 2020, 03:22:23 PM »
The outer cylinder pedestal has an interesting shape and as I do not have the casting for this I needed to make it up. I am using a piece of flat bar drilled 8BA clear at the right distance to mount two 6.35mm OD 8BA threaded pieces of steel dowel on to it. Between which I will mount the remains of a piece of slightly wider steel bar, which has been drilled 6.35mm at the right distance to slip over the tops of the two dowels. this is then silver soldered together. And (other than getting the height wrong on the first one  :Doh: ) these are then milled so that one fits inside the other. I am deviating from the drawings here as the original engine seems to have round bearings outsides to the main bearings while the drawing shows square  :headscratch: This means that the top and the bottom of the bearing pedestal have to mount together rather than leaving a square hole for the main bearing. Later they will be bored to suit the bearings.

I am using brass for the main bearings, this is not really an ideal bearing material but this engine will not be run much and the cylinder is bronze so I want a different material for the bearing and they are easy enough to make a second set if I do wear the first set out  ::)

The big bearing measures 16mm outside so I could not use my stock piece of 12.7mm brass flat bar that I have already soft soldered together for this task but had to cut down a piece of 19mm square  :disappointed: The trick with these bearings is to turn the outside first and once mounted inside a collet bore to suit. If you try boring without any outside support the soft solder may allow the two to open up and the result is a useless piece of scrap  :toilet_claw:

The bits are very slowly coming together... I just wish I had more time  :wallbang:

Jo
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Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #25 on: February 14, 2020, 05:54:02 PM »
I managed to make the second bearing block today and to bore the two so the bearings fit  :)

I ran out of time so did not manage to split the bearings so that the larger bearing could be fitted round the cylinder pivot surface  :-\

Jo
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Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #26 on: February 15, 2020, 03:31:26 PM »
Having parted the bearings by gently heating them I could then look to fit the cylinder between the two bearings and make sure it is free running.

I also made up the piston rod and put the piston in the cylinder but the other end of the rod is going to need a bit of thinking about  :noidea:

Jo
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Offline Alyn Foundry

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #27 on: February 15, 2020, 04:50:39 PM »
Hi Jo.

Looking at the " wood cut " drawing at the beginning of your thread it would appear that the big end bearing was just " pinched " on one side only. This being its adjustment for wear.

I can understand your problem if the crankpin has a solid flange at either side.

Cheers Graham.

Offline Jasonb

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #28 on: February 15, 2020, 05:02:06 PM »
Yes, probably best to make the inner pin flange a loose one or make a crank with a boss at the pin end to bring it out to thickness.

Have you been printing any useful bits lately?

Online Jo

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Re: B Hick & Son 1851 Oscillating Engine
« Reply #29 on: February 15, 2020, 06:13:36 PM »
I think I have a solution for the big end  :noidea:


Have you been printing any useful bits lately?

Nope, while the 3D printer has taught me a lot, and I have already had more than my money's worth out of it, it is but a tool which can wait for the appropriate time to be used  ;)

Jo
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