[GreenKeys] TD gears for the dual head 28 ASR

[George B. Hutchison]

Well, time for the old guy to rattle on a bit and divulge a not too 
closely kept secret.

The simplest way to make that dual head base useable is to go down 
to your local industrial supply and buy a length of 3/8" diameter 
centerless ground rod.

Borrow a good shaft from a single head TD, remove the rear to front 
shaft from the dual base, take yer handy-dandy dial caliper and do 
some measurements and make a new shaft which will be just a bit 
longer than the one you removed from the dual base, and turn a new 
shaft for the dual head.

The shaft has to be cut a bit longer than the original, and you'll 
have to cut a new C-clip groove for the bearing in the new one, and 
machine the new end to fit the gear from the single head shaft, 
positioning said gear to mesh properly with the drive gear on the 
inner TD head.

Power from the new shaft will drive the inner head, and inasmuch as 
the inner head is engaged with the intermediate shaft in the dual 
base, it will drive the outer TD just fine.

I've made about six of those shafts in my lifetime, and on a good 
lathe takes no more than about fifteen minutes.

And it works spiffy, and you can use all of the standard 28 TD gear 
sets.

W7TTY