Author Topic: Muncaster No1 with Reverser BUILD with Drawings  (Read 3263 times)

Offline Jasonb

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Muncaster No1 with Reverser BUILD with Drawings
« on: March 07, 2020, 07:17:51 PM »
A couple of the members on ME forum can take the blame for this one as their versions got me thinking about making my own, one to muncasters original design and one to that by Julius DW..

I took the basic design out of Muncaster's book and redrew it in metric at a slightly larger 12mm bore (7/16" original) x 20mm stroke. to keep a constant theme to that of the entablature engine I also drew and CNC cut a curved spoke flywheel from a slice of cast iron.

Having recently repaired a Mamod traction engine for some one I thought adding a reverser that works on the same principal would make things a bit more interesting both in the design, build and eventual running stages.

Quite a quick build even for me, looking at the dates on the photos I started it on a Friday evening and it was running 8 days later on the Saturday morning. The video starts off with direction and speed being controlled by the reverser then after about 60 seconds I'm just using the flow valve to alter speed, compressor regulator set to about 10PSI throughout. It will run by blowing down the airline but I did not think you would want to see film of me slowly going blue in the face.

After taking the video I refilled the small 12lts tank on my compressor and then switched it off at the mains before setting the engine running at approx 100rpm. It ran for 38minutes which is rather good as my compressor is a bit on the loud side

<a href="https://www.youtube.com/watch?v=ToUX_Df6GQ0" target="_blank">http://www.youtube.com/watch?v=ToUX_Df6GQ0</a>
« Last Edit: March 30, 2020, 10:16:10 AM by Jasonb »

Offline Admiral_dk

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Re: Muncaster No1 with Reverser
« Reply #1 on: March 07, 2020, 07:57:54 PM »
Looks great and runs really good  :praise2:

Are the speed / directional control done by moving the axis of the cylinder left or right .?.  :thinking: ... it certainly appears that way in the video.

Offline Jasonb

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Re: Muncaster No1 with Reverser
« Reply #2 on: March 07, 2020, 08:10:53 PM »
Yes, the pivot for the cylinder is mounted in an offset hole in a bush which when rotated moves the pivot point. There is one central inlet and two exhaust ports, one either side. More detail to follow.

Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD
« Reply #3 on: March 30, 2020, 10:15:20 AM »
So with us all on lock down I thought it would be a good time to get a set of drawings together and write up the build if anyone wants a small project to pass some time. This time rather than separate drawings I have put all 10 sheets into one pdf which should make it easier when looking over them on the computer as you can scroll up and down rather than having to open multiple files. I have also done a Bill of materials for those that like to have one, note that sizes are generally of the finished part so make your own allowances for holding, parting etc.

In most cases materials can be substituted as well as methods, anyone with queries please ask. Also if you find anything wrong or missing on the drawings please let me know and I will update as needed.

Column

Start by facing the end of your 15 or 16mm stock and then form the spigot on the end followed by a small ctr drilled hole. The material can then be pulled further out of the chuck and tailstock support used while the tapered section and decorative beads are turned.



Transfer the part to the mill and hold by the remaining bar in a collet block or indexer to mill the two flats at the top followed by drilling and reaming for the bearing.



With the work back in the lathe form the small boss for the oil hole before parting off. The oil hole can be drilled while lightly holding the top of the column in a collet or in the 4-jaw, you could even leave it until later and just use the bench drill.

Bearing

This is a straight forward turning job, the column can be used to gauge the outside diameter and the 5mm hole is best reamed. The bearing is Loctited into place with 1mm protruding on the cylinder side and then the oil hole drilled through but don't do either of these things yet.



Crankshaft

A very easy part to make from either Precision Ground Mild Steel or Silver Steel (Drill Rod) but leave it say 1.0mm over length for now.

Crankpin

Another simple part from Silver steel

Crank Web

Start by forming the 8mm dia boss on the end of a piece of 25mm dia steel then drill and ream 5mm. Part or saw off leaving the web 1mm over thickness.



Transfer to the mill, locate the ctr and then move 10mm to one side to drill for the crankpin.



To mill the tapered sides slip the crankshaft material into the 5mm hole letting it rest on the vice jaws and the 2.5mm drill into the pin's hole but raise this up 2.75, you can see the black 2.8mm drill shank I used for this and then mill one side before repeating for the other though there is not so much to hold this time around so light cuts after sawing off most of the waste.



After rounding the corners to the final profile with a file the web can be Loctited to the crankshaft with 638 or 648 and set aside to dry. Then holding the shaft preferably in a collet a couple of cuts can be taken across the end of the web & shaft to bring them both to final size. deburr and then Loctite the pin into place.

« Last Edit: March 30, 2020, 02:10:51 PM by Jasonb »

Offline J.L.

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #4 on: March 30, 2020, 12:57:44 PM »
Wonderful project Jason.
A perfect little model to bring out and dispay and impress!
Cheers...John

Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #5 on: March 31, 2020, 01:52:34 PM »
Thanks' John

Before going on with the build I'll explain a bit about the reverser as the parts for that are the next to be made.

As I mentioned I recently repaired a Mamod traction engine for someone and got the idea from the reverse lever fitted to them which is simply a pressed steel lever that rotates and has an eccentric hole for the cylinder pivot.



There are three ports on the base, a central one that is the inlet with teh ones either side acting as exhausts. As the cylinders pivot point is moved from one side to the other it will use two of the three holes depending on what side of ctr it is.

So with the lever down the pivot moves towards the right when viewed from the back.



Looking at the front you can see that the cylinder will oscillate between the left exhaust and central inlet.



If the lever is now moved upwards so that the pivot is now on the opposite side



Which means that the cylinder is now oscillating between the right hand exhaust and central inlet, this has the effect of making the upward power stroke take place when the crank is on the other side of centre thus reversing the direction in which the flywheel rotates. An added bonus of this arrangement is that with the lever placed somewhere between these two extreams the amount of time that the ports are open for is altered so the reverser can also be used to control speed and or save air/steam.




Offline Johnmcc69

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #6 on: March 31, 2020, 02:01:35 PM »
 :ThumbsUp:
 Nice work on the Model & drawings Jason!
Quite a nice little engine.

 :cheers:

 John

Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #7 on: March 31, 2020, 02:19:56 PM »
Column Base

This is probably the most complex part of the model so take your time.

I chose to make mine from a slice cut off a piece of 50mm dia cast iron bar though it can just be squeezed out of 1 3/4" material if you have that to hand. Once the bar had been faced off both sides in the lathe to the required 11mm thickness it was transfered to the mill to form the basic 31 x 37mm rectangle.



Holding the block in the vice with what would be the port face upwards the work was centred in X and the bottom edge located so that the tree 2.5mm ports could be drilled to depth and then the hole for the pivot drilled and reamed 10mm. To save putting any holes in the wrong place I used a Sharpie to roughly indicate where the various features should be.



If you don't want to have the air supply come in from the side of the base then the work can be turned the other way up and a 3.5mm hole drilled to join the inlet port and then tapped M4 x 0.5. so that the air can come in from the back of the column.



Next the sides can be milled away to form the feet followed by drilling and tapping M5 x 0.5 either side for the exhausts.



To form the detent arc I chose to hold the job in my mill vice which was in turn mounted onto the rotary table but the Arc could just as easily be turned on the lathe and then the excess milled away. The Vee notches were cut using a spotting drill at 15degree intervals, again if not using a rotary table they could simply be filed with a needle file.





The two 3mm holes to mount the engine to the base and 2.5mm air supply up to the inlet port are simple enough, filing buttons can be used to shape the two feet.

Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #8 on: April 02, 2020, 05:00:44 PM »
After turning the pivot bush it can be held in a collet block to firstly drill and ream the 3mm hole.



The collet block can then be repositioned so that the 1.5mm hole can be drilled at right angles to the first.



The size and shape of the adjusting nut is not critical and a diamond knurl will do if you don't have straight wheels. The pivot shaft is just a simple rod threaded at either end and hopefully you can find a spring of approx the right proportions to that shown.

The reversing lever is bent from 1.5mm rod and Loctited into the pivot bush.

The column can also be joined to the base at this stage with Loctite if you have a good fir or JBWeld if there is any movement. To endure the part face is at right angles to the bearing hole lay the two parts onto a flat surface when bonding and if you have a vice that opens far enough that can be used to holed them together while the adhesive dries. Once it has the cankshaft bearing can be loctited into place with 1mm protruding on the port face side and then the oil hole drilled through.

You should have something that looks like this if all has gone to plan.


Offline Bearcar1

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #9 on: April 02, 2020, 08:03:03 PM »
THAT, is a cool looking engine Jason, And Thank you for sharing. I really enjoy seeing build photos and those really help me get my head around the different steps required. Thanks again,  :DrinkPint:


BC1
Jim

Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #10 on: April 03, 2020, 07:02:09 PM »
Thank's Bob

The cylinder can be cut from 25mm or 1" stock without the need to offset the bore. Start by facing off and then reduce the end to 20mm diameter followed by turning the 14mm outside diameter with a parting tool down to where the top of the port face comes. While still in the lathe drill and then bore to the finished 12mm dia.



The part face can then be milled flat and while in the vice drill the inlet hole 2.5mm, tap M3 for the pivot pin taking great care not to let the tip of the drill go deeper than 3.5mm then finally add the vent hole just below the flange. The port face can be lightly rubbed onto some 1000g wet and dry laid on a flat surface to remove any slight raised material around the holes this also keeps the edge of the inlet hole nice and crisp stop air bleeding between ports if there is any chamfer to the edge.



With the port face against the fixed jaw the three tapped holes can be orientated easily.



Mill the two sides of the cylinder flat and then slip a piece of rod through the bore and rest that on the top of the vice jaws and take a series of cuts rotating the work about 5degrees between each cut which will give the curved surface as a series of facets.



Which can easily be blended with a file and finished with Emery cloth.


Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #11 on: April 05, 2020, 04:27:56 PM »
Top Cover

The cylinder top cover helps guide the piston rod so turn the 1mm deep spigot and ream the hole at the same setting. Then transfer the work to the mill so that the three holes can be drilled while you have plenty to hold.




Then saw off from the bar and turn the external profile, if you like this can be a simple straight spigot 7mm dia but the curve looks a bit nicer and more like a casting when painted and the ring around the edge left bare.



Bottom Flange

The bottom flange can be made in much the same way but with threaded holes and is fitted to the end of the cylinder with Loctite, 648 if you intend to run on steam.

Bottom Cover

The bottom cover is just a dummy and made like the two items above. You could omit this part if you wanted in which case don't bother to drill and tap the bottom flange.

Big End

I started with some 3/8" round stock and turned the end down to 4.5 mm and tapped M3 before using the spin indexer to mill the 5mm square and drill & ream the cross hole. After sawing off from the bar filing buttons can be used to round over the end.



Piston Rod

Simply a piece of 3mm stainless steel threaded M3 at one end, use a tailstock die holder if you have one to make sure the big end screws on squarely.

Piston

Rough this out a little over diameter and cut the oil grooves before attaching to the piston rod with Loctite, 648 again if running on steam. Once this has cured hold by the rod in a collet, split bush or 4-jaw and skim the piston so it is a sliding fit in the cylinder.





Offline Jasonb

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #12 on: April 06, 2020, 07:04:53 PM »
Exhaust Pipes

These can be any material but I turned down some copper and drilled it to form suitably sized tubes before threading the ends M5 x 0,5

Base

I have shown two options for a base on the drawings, the oval that I used and a square which will be easier for many to machine. If you do want to make the elliptical one and don't have CNC then the drawing can be cut out and used as a template if you want to shape your own manually.

I started buy drilling the two 3mm through holes and the blind 2.5mm one that lines up with the inlet hole in the bottom of the column base. Then drilled in from the edge to this hole with a 4mm drill as this gives a nice push fit hole to poke a piece of 4mm PVC air tube into. The through holes were used to mount the Corian on a block so it could be held clear of the mill vice and a contour cut used to form the oval shape followed by a couple of passes to cut the decorative moulding on the top edge using a router cutter but a round over milling cutter would do the same job.





<a href="https://www.youtube.com/watch?v=myYOtlfi8Eg" target="_blank">http://www.youtube.com/watch?v=myYOtlfi8Eg</a>

Flywheel

The final part needed is the flywheel, I decided to have a go at making mine on the CNC so turned a "blank from cast iron bar.



The contour lines left bar the cutter are more pronounced than they should have been, I thought I had ordered a 4mm dia cutter with 1mm radius corner but I had actually clicked on one with a 0.2mm radius which is almost just a flat ended cutter and did not look at it before using :-[ Just needed a bit more work with the Dremel to get it ready for paint.

<a href="https://www.youtube.com/watch?v=-yAOLGpnjCg" target="_blank">http://www.youtube.com/watch?v=-yAOLGpnjCg</a>

Once the milling was done the flywheel can be held at an angle to drill and tapped  for an M3 grub screw.



I expect most won't be able to CNC a matching flywheel so have listed the Stuart Progress and Reeves Nicholas flywheels as suitable alternatives for those wanting a cast flywheel, or one could simply be turned from a slice of 62.5mm bar with a recess cut into each face and say 6 equally spaced holes drilled in the resulting web.

All the parts can now be put together checking for any tight spots as each piece is added which make sit easier to identify the culprit than if you assemble it in one go and then find a problem.





If all is well I suggest a test run before painting as if anything needs attention you don't risk damaging the paintwork. If all is well then strip the engine down, degrease and mask up where you don't want paint before priming and topcoating, I chose to use the same off white that I did the Muncaster Entablature engine in as there was still some paint left in the can.







<a href="https://www.youtube.com/watch?v=ToUX_Df6GQ0" target="_blank">http://www.youtube.com/watch?v=ToUX_Df6GQ0</a>

Well that's another one to go onto the shelf, I look forward to seeing a few of these over the coming weeks from those that are locked down in their workshops.

J





Offline gary.a.ayres

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #13 on: May 02, 2020, 09:21:24 PM »
Elegant!

Offline crueby

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Re: Muncaster No1 with Reverser BUILD with Drawings
« Reply #14 on: May 02, 2020, 09:49:46 PM »
What a gem!

 

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