Tangler's Air Cooled Farm Boy

[Twizseven]

Rod,
Seeing your comments about importing images from Dropbox, I have just done a search and I came across a site giving a simple way of adding pictures from dropbox.  You may have seen this and tried it but I thought I would make the suggestion.

When you paste the link change the end of the link from ?dl=0 to ?raw=1

The image below has been inserted using this method.



This is the first time I have tried this, but will use this method next time I post to hopefully put pictures in sequence rather than the end.

Best Regards,

Colin

[tangler]

That works!

Thanks, Colin.

Stay well,
Rod

[Twizseven]

Rod,

Glad it worked for you.

All I have to do now is "remember" how to do it when I next post.

Best Regards,

Colin

[tangler]

I thought I ought to see if this piston/ring combination feels OK in the cylinder and this seemed like a good point to try fastening the cylinder to the frame.  To this end I made a simple jig to position the stud locations



I also turned a plug to locate the jig on the frame and drilled the holes for the studs using this rather precarious arrangement





Then tapped the holes on the UPT



Drilling the clearance holes in the cylinder was somewhat simpler



It turned out that there is a clearance issue with the big end because I elected to use studs and lock nuts rather than a simple bolt through the cap.  I'll have a think about this.  However I tried the piston in the bore and it slides nice and freely.  There is a little bit of stiction at the start of movement but I don't think this will be a problem.



Stay well,

Rod

[Jasonb]

It's coming along Rod, do you get a good vacuum/bounce with the end of the cylinder covered by your hand?

Looks like a bit of shaping of the big end cap may get you the clearance you need.

[Roger B]

That precarious drilling set up looks the sort of thing I would use (actually the drill looks much like mine).

Looking good   

[Brian Rupnow]

Tangler--I am following your thread with great interest. I'm in some medical "downtime" at the moment---can't work, but I can still read threads.---Brian

[tangler]

Thanks for the encouragement chaps.

As Jason mentioned, there is room to reduce the height of the big end bearing cap, which I did, leaving an ornate bit in the middle.



Not sure of this is prototypical - perhaps more Victorian Egyptian revival than Amanco 



Anyway, it now fits



While I was in the mood I thought I would make the main bearing caps a little less boxy

I trimmed down the bolt seats and then rounded the lump in the middle with a 5mm radius cutter



Not really happy with that so I trimmed a bit off the top and tried my other radius cutter which is 3mm radius



Better but not best.  A bit of edging with a ball nose cutter as well.





Too ornate?  Regarding the bearing caps, what was full size practice for holding them down:  studs and nuts, hex bolts, slotted cap screws or...?

Thanks for stopping by,

Rod

[Jasonb]

Looking through the various ref photos I have for the open crank engines that I have made there is no set fixing type, some are bolts, some studs with single nuts and others including the Assoc Hired Man studs with nuts & lock nuts.

probably a bit too ornate for me I would likely have gone for just a rounded top centred on the bearing ctr with a couple of flats possibly partly counterbored if needed.

You have not drilled for any oil cups yet so what about taking say an 1/8" ball nose cutter and forming a trough along the length of the raised part for oil to sit in and a small hole down through cap & bearing.

[tangler]

I've worked out how to do it properly



That's better



Rod

[Jasonb]

 

[gbritnell]

Very nice work!

[scc]

Ditto                 Terry

[Dave Otto]

Nice progress!

Dave

[tangler]

Thanks for looking in guys.

I sympathise with Terry, it took me all afternoon to make 4 studs:



I think my M5 die is suspect - I've ordered some un-split dies from ARC

Making the valves next.  Long debates with myself whether to turn down from 3/8" stainless steel or fabricate from 1/8" precision ground stainless with a braised on head.  I opted for the former.  Jerry retains the springs on the valve with a keeper restrained by a 1/16" cross pin.  I elected to use E clips since I have a whole selection box of them.

First, turn the groove for the E clip with the hacksaw parting blade



Then turn the rest the shank down to 1/8" and polish



And part off



Then reverse into an 1/8" collet and finish of the head with light cuts at 45 degrees



The springs were next.  This is my selection box of spring wire bought many years ago from (have you seen my cat? ) Whiston - remember him UK guys?



The drawings call for 6 and 7 turns respectively in just over an inch but the coarsest thread I can cut is 8tpi so that will have to do.  This is my spring winding tool, just a lump of mild steel with a small notch filed in the end



It works OK, I don't use any tensioning, just feed the tool so that it squeezes the wire on to the mandrel.  I had to have a couple of goes to get the mandrel size correct - an on line calculator made the spring a bit big in diameter.



The keepers were simple turning jobs and here's a little family shot



Cheers,

Rod