srinath wrote on 04/03/13 at 17:07:07:


That's the plan when I start making them Srinath,  both in Stainless and Mild Steel for those that want to paint them.  I will use beefy 1/4" stock for making them.  My lathe will do both right and left hand threads, so the threading won't be an issue for me on making them.

R.F.

WD wrote on 04/04/13 at 09:50:16:

Thanks for the advise.  I will ditch the idea of the mild steel for those that want to paint then. I was also just looking at my conversion tables and seems I was thinking wrong on size anyways,  I need to use either 5/16" or 3/8" stock as 1/4" is basically the same size as the stock rod to begin with. although with it being SS it would be much stiffer but better safe then sorry so I should make the step up to the larger stock.

As for the aluminum wouldn't that be just as likely to bend as the stock rod,  even with it being a bigger diameter rod?

R.F.

Dave wrote on 04/04/13 at 11:27:45:

Thanks Dave,  5/16" will be my target for the first batch of rods then.

R.F.

WD wrote on 04/04/13 at 12:34:01:

The steel place I use can get me just about anything I want.  I was considering using 316 marine grade stainless for the rods, but after looking up 416 I just might consider it as it has better machineability with similar corrosion resistance.

I will also consider doing the aluminum ones for those that want them in aluminum.  

The machine I have is very similar to the Smithy unit, but has higher spindle speeds available at the lathe part of the machine.  When I was searching for my machine I also considered the Smithy unit as well.

R.F.

I didn't mean the machine called smithy... coal forges and anvils. Bad phrasing on my part. Most of my shop equipment is ancient.

srinath wrote on 04/04/13 at 13:51:08:


On both materials I would do a slight taper for the transition from the threaded are to the solid rod area, to relieve the sudden weak area from the cut threads.  Even with machining the same size threads on a piece of bigger stock will make the whole part stronger as a whole, since the main issue with the shift rod is not breakage of the threads, but bending of the rod itself because it is to small in diameter for the job that it is supposed to be doing.

I also have plans for redoing the whole shift rod linkage period to a much better setup, but to do that I will need a spare set of levers both front and engine case side to do this with.  My plans are to make them easier to maintain the lubrication on them plus make the shift linkage smoother at the same time.  I can't do anything about the smoothness of the gear box itself, but I can make the shift linkage pretty much bulletproof.

R.F.

Sorry,  I'll refrain from further posts about it in this thread.  

rfw2003 wrote on 04/04/13 at 14:53:45:


Actually there may be a way to make this cheaper and better. See machining is $$$, cutting threads is even more so, labor intensive, arm breaking work not to mention failure prone ... so your best bet is to use bolts in the ends. You can get those inexpensive and they can be hard as a rock, and if you break those in use, the end use can replace it cheap. The trick is to make it so it wont spin around when you're trying to install and adjust it.

My thought is - you get the bolts with allen heads in a good hard material. Get the same temper steel tube that fits tight on the bolt head. Drill them both side ways with a small size drill, like 1/16th or 3/32. Small. Then put in a tension pin. You're done. If they fail in regular use, the end user can get em out, pull the tension pin and replace the bolt.

Tapping steel even mild is arm breaking work, hardened - you're gonna need a few 1000 in tools. Acorn dies and possibly a serious machine made for tapping. Aluminum is better, but still will take up a lot of your time, and at the end be non user serviceable.

Cool.
Srinath.