Author Topic: Little Wall  (Read 2402 times)

Online steam guy willy

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Re: Little Wall
« Reply #15 on: April 14, 2022, 04:26:56 PM »
Is this the same  Mr wall that made the " Wall auto wheel "the attached to a bicycle  early in the 20th century ??

Nice construction  :praise2: :praise2:

Willy
« Last Edit: April 14, 2022, 04:52:04 PM by steam guy willy »

Offline Johnmcc69

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Re: Little Wall
« Reply #16 on: April 14, 2022, 04:28:59 PM »
 :ThumbsUp:
 Nice work Jason!
 That's looking real good!

 John

Offline Jasonb

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Re: Little Wall
« Reply #17 on: April 14, 2022, 06:44:39 PM »
Thanks for all the comments, will keep the posts coming now my PC has been repaired.

Willy, going by the Union Jacks in your image I don't think it is the same as my Mr wall was from the US. Some details of Elmer Wall here on the Model Engine News site. But I do like those little inside wheel engines.

http://modelenginenews.org/gallery/p18.html

Offline Johnmcc69

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Re: Little Wall
« Reply #18 on: April 16, 2022, 01:39:54 AM »
Hi Jason, any thoughts about creating & posting any working drawings of this?  :stickpoke:

 John

Offline Jasonb

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Re: Little Wall
« Reply #19 on: April 16, 2022, 07:40:39 AM »
You would not want to see my working drawings :-[

I tend to model it in 3D and then just take off the sizes I need on a quick hand drawn sketch for the manually made parts, CNC cut stuff does not need a drawing. Funny enough it seem from a recent thread over on ME that quite a few people do similar. These are the "working drawings" for the engine I've just completed :)



Though if you are able to open Alibre files or split the individual components from a STEP file then I can post those

Online Jo

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Re: Little Wall
« Reply #20 on: April 16, 2022, 07:48:48 AM »
You would not want to see my working drawings :-[

You have been working with Alyn Foundry too long  :lolb:

Jo
Enjoyment is more important than achievement.

Offline Jasonb

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Re: Little Wall
« Reply #21 on: April 16, 2022, 07:55:17 AM »
Yes there are those of us who intuitively seem to know what's required and don't need a fully drawn up set of plans. Though I will produce them for any designs I publish and maybe his too.

He's been sending me more fag packet sketches and some of his old etchings recently and asking about patterns, I'm sure it's a ploy to get me to like castings :disagree: ;)

Offline Jasonb

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Re: Little Wall
« Reply #22 on: April 16, 2022, 07:30:51 PM »
The engine has a rather shapely combined inlet and exhaust manifold that would have been an aluminium casting on the original and is an ideal candidate for CNC machining as that handles the curves very well. The passage s would have been cast in using cores and I did toy with the idea of making in two halves in brass so the passage could be milled out and then solder the two together. In the end I worked out tat a couple of carefully placed drill holes would meet in the middle and hopefully not come out the side so a one piece aluminium part was on the cards. You can just see the orange ctr lines of the holes on this drawing together with their depths and angle of drilling.



A block of 6082 was machined to overall size and held in the vice to first rough out to half depth using an adaptive tool path using a 4mm flat ended 3-flute cutter. I'd put all the holes in earlier while it was an easy to hold rectangular block

.

Then the "steep and shallow" path was used while I still had access to refine the shape. I think that was a 3mm ball nose 4-flute cutter but may have been 4mm.



It was then put back into the vice the other way up and a mirrored version of the CAM used to complete the other side as the top and bottom flanges are different shapes.



I'm quite pleased with how it came out, probably should have run a "pencil" path that has the ball nosed cutter run along all the internal fillets which would have got rid of the slight steps.



I spent a little while smoothing this and the crankcase casting with needle files and then had a go at bead blasting them with a very basic Aldi spot blaster which gave the desired finish but I need to get small cabinet as glass beads on the garage floor can be a bit slippery ;D



A couple of photos of the engine coming together taken prior to the bead blasting to round things off for tonight.













« Last Edit: April 16, 2022, 07:36:42 PM by Jasonb »

Offline rklopp

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Re: Little Wall
« Reply #23 on: April 17, 2022, 06:04:02 PM »
This setup seems sketchy. (Photo of part in vise after machining second side.) Did you not have any support underneath the part?

Offline Jasonb

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Re: Little Wall
« Reply #24 on: April 17, 2022, 06:36:00 PM »
I don't think I did have anything as it was a while ago that I did it, though could have been a packer under the rectangular flange.

Offline Jasonb

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Re: Little Wall
« Reply #25 on: April 21, 2022, 07:32:02 PM »
The crankshaft started life as a length of EN8 round bar and was reduced down to a rectangular section using a 5 insert face mill regularly flipping the bar over to minimise the risk of any distortion caused buy taking a lot of metal off one face in a single go.



I then used an angle plate and 20-40-80 block to give me two reference faces to clamp the now rectangular bar to so that the ends could be centre drilled ready for subsequent turning



To avoid the knock, knock, knock of the interrupted cuts I milled out most of the waste between the webs with a 10mm cutter



Over to the lathe and a soft ctr held in the 3-jaw was trued up and the chuck jaws also work well to drive the dog. I use a GTN2 insert that has been modified with a Dremel cut off disk to remove the cutting edge in the middle to do the last few finish cuts moving the tool from side to side



After milling away the waste at either end and fitting a packing piece between the webs the shaft was turned down to the required 10mm diameter 8mm diameter and the ends reduced ready to be threaded M6. The shaft was then set aside until the flywheel and pulley were ready so all the tapers could be cut with the top slide at the same setting.



With the shaft diameters finished I could use that as a gauge to bore the bronze bearings which are just simple flanged ones



There are bolt on counterweights on the crank webs, I started by turning a piece of bronze.



Then milled some slots to produce the two "half circle" weights



And then a slot to fit over the crank web's end and a hole for the retaining cap head screw



A couple of shots of the crankshaft with it's weights and the bearings one of which is fitted to an end cover.






Offline Dan Rowe

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Re: Little Wall
« Reply #26 on: April 21, 2022, 08:27:02 PM »
Nice sequence of making a crank. Is EN8 a stress-proof type of steel?

I really like the double-dogging photos, I have never seen that done before.

Cheers Dan
ShaylocoDan

Offline Jasonb

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Re: Little Wall
« Reply #27 on: April 22, 2022, 07:05:37 AM »
No it's nor stress proof hence the care taken to machine a bit of each side so the internal stresses don't cause movement, you can get it in hot rolled which should be less risk but smaller diameters >2" are usually sold cold rolled. Its a medium tensile steel but still quite easy to machine. In the US it would be 1040 0r 1045

Best not go googling for more images of Double Dogging, could certainly have a different meaning over here :naughty:

Online steam guy willy

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Re: Little Wall
« Reply #28 on: April 22, 2022, 12:15:47 PM »
Wow this is looking really good  and the needle file work has worked really well  :praise2: :praise2:

Willy

Offline Dan Rowe

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Re: Little Wall
« Reply #29 on: April 22, 2022, 01:18:32 PM »
Best not go googling for more images of Double Dogging, could certainly have a different meaning over here :naughty:

Thanks for the info on EN8.

That last bit made me spit out my coffee laughing so really thanks for that laugh, good one.

Cheers Dan
ShaylocoDan