Swifty's build of Howell V4

[gus]

Thanks for showing finished piston and rod assembly. I get a fair picture of how the piston ring retain the gudgeon pin. Next week locked up to do pistons and rods. Again thanks for showing the way to machine the rods.


Ned Kelly Gus.

 

[jimjam66]

Holy cow! Is that a regular match for scale? Them's some tiny pistons and conrods! If I may ask, how did you cut the central slot of the 'Fork'? I assume (but am prepared to be wrong) that you did it as the final machining operation? Sorry - just re-read your post and it was the first, not the last.

 

[Swifty]

David, I milled the slot for the forked con rod with a normal end mill, just held the part upright in the vice, picked up the centre, roughed it out, then finished to width. I was going to use a slitting saw with the part lying down, but all my saws would have needed a few cuts as I didn't have a wide one.

It's a normal everyday match, I do have a couple of boxes of longer firelighter matches in my camping gear, maybe I should use one of those to make the parts look even smaller . The piston diameter is 7/8", so maybe that will give a better idea of scale. One thing that I notice while turning small parts, I think that I need a stronger pair of glasses to see detail properly.

Paul.

 

[Art K]

Paul,
Your piston and rod assembly is looking good!
Art

 

[Swifty]

Managed to finish the crankshaft off over the last couple of days, milled away excess material on the webs to form the counterweights, drilled and tapped oil passages etc. I made the threaded end a bit longer than the drawing calls for, I have an idea of using a one way bearing and electric starter motor for this engine.



Paul.

 

[Swifty]

I just couldn't help myself, I had to do a trial assembly of the main parts. I didn't bother with the cylinder sleeves, pistons or rods, and only one pair of follower guides are there.






Paul.

 

[Swifty]

I meant to mention in the last post, I spent a few hours tapping all the holes in the block. There were 43 holes that needed tapping, with the majority being 2-56 and the rest 4-40, taper tap then bottoming tap. The block was too big to fit under my tapping fixture, so all were done with the use of a guide block with a hole in the middle to suit the taps. I was certainly glad to get then all finished without breaking a tap. The taps were held by a small brass disk with a hole to suit and a grub screw on the side, much less chance of applying too much pressure.

Paul.

 

[gus]

Congrats. No taps broken. 43 tapped holes. Thats a pretty lot of of tapping.I would tap at most 5 max at a time.Take tea break for 15 mins. Very nerve racking. 4-40 is about M4?. M3 not too bad. M2 would be very risky. Trust your 4-40 taps were brand new or still very sharp. Plenty of Tapmatic Fluid used???

 

[jimjam66]

Exciting times! The end is in sight for that beauty!

 

[Swifty]

Been working on the rocker arm clevis and valve push rods. I'm waiting for a 1/8"slitting saw to arrive so I can mill the slots in the clevis.



Paul.

 

[Swifty]

I've been doing a little bit whenever I have a chance, I have made the distributor drive case and camshaft end cover. At the moment, I'm struggling to get a supplier for the 2 mitre gears for the drive, I will just have to broaden my search.




I'm almost finished with the oil pump, I just have to put a full radius on the ends and do a final assembly. I made the pump from round bar stock, used the 4 jaw chuck to machine the top plate, and did the rest of the work on the mill.




Paul.

 

[Cogsy]

Looking great as always Paul. I've used Stock Drive Products - http://www.sdp-si.com/ - in the past and they were easy to deal with. The shipping is reasonable and was auto-calculated online so I browsed, ordered and paid without ever having to email anyone. They also have a massive range so you should be able to get what you need.

 

[Swifty]

Thanks Cogsy, I have used that site in the past to check gear data, but for some unknown reason I never thought of searching for the gears that I wanted. I always searched for 48 DP mitre (miter for the USA) gears, but I never saw them come up. It certainly looks like they have the gears that I want.

Paul.

 

[gbritnell]

Outstanding work Paul. I have seen several of these engines running over the years and they are great performers. I'm sure you'll be very happy when you get to that point.
gbritnell

 

[Gerhardvienna]

Hi Paul
Great work!
Just fell over your method to do the gears, this is phantasitc! I`ve never seen it that way before, this is the way I was looking forThm:
Gerhard

 

[Swifty]

Some may be wondering, why don't I just make the mitre gears. Well, I would have to buy a cutter for them, and they are not cheap in DP size, each tooth on the gears requires 3 passes with the cutter, but the biggest problem is that they would be darn hard to see to cut. So, best to buy what I need rather than pay for a cutter for a one off job.

Paul.

 

[jimjam66]

Did you make the oil pump gears, Paul? The scale makes my eyes water ...

 

[Swifty]

Hi David, yes I made the gears, but I had to make a hob style cutter first, post 95 onwards shows a few pictures of the process. The gears are 13T, 48DP, .312" OD x .150" thick with a .125" hole in the centre. I made them as a bar length and parted them off very carefully, the biggest problem was removing burrs from the teeth after I parted them off.

I will lap the mating faces of the gear pump prior to assembly to avoid any oil leaks. I'm quite happy that all went well, the gears have to be a neat fit in the bores in order to work properly.

Paul.

 

[ruzzie]

Have you tried these guys for gears
http://www.smallparts.com.au/store/categories/gears+mitre/
http://www.hobbyparts.com.au/store/partslist/kitsgears90degree/kitsgears90degree/a/1/


Paul

 

[Swifty]

Thanks Ruzzie, I will check them out today, the main problem is that they have to be DP imperial gears.
Module gears just are not the right dimensions.

Paul.