Planetary gear reducer.

[John Foster]

I have just been given a junk Dunlap 6" lathe. I was surprised to find that they used a planetary gear reducer in place of the backgear. It is a neat little unit except it has a nice "window" in the housing. Now the window is great for figuring out how this little unit worked but with about 1/3 of the ring gear gone it doesn't work too well. Also exact number of neeeded teeth for replacement. Figuring it I came up with 96.6 teeth and while I have cut a few gears with partial teeth they don't seem to work too well.
Does anyone have a parts list for this antique and if so what is the number of the pot metal casting that contains the ring gear. It looks like a lot of work but might be able to make a new one but would sure rather find one.
In checking on planetary gears I find they recommend a 20° pressure angle be used rather than the more common 14 1/2° for the gears, sun and ring. Mostly for proper clearence on the ring gear teeth.
Thanks John

[JCHannum]

You might try a Google search on Dunlap or Craftsmen lathe. It was sold under both names, as well as the AA name. There is someone making reatoration parts for these lathes, but I cannot find the link.
(If I ever saved it.)

[J Tiers]

If you go to the metalworking dropbox (rec crafts metalworking) in 1999 retired files there are some file labeled "AADOCS".

In there is a complete manual for a 109.20630, a common variety of those. If it is a 702, I have somewhere a copy of the much shorter "manual".

[John Foster]

Finally noticed the name tag. It is Model Number 109.0703. Sears does not list it, assuming I used their site correctly.
J Tiers, sorry but I am not familiar with your source, would you give me the web site. Thanks, John

[This message has been edited by John Foster (edited 07-01-2004).]

[J Tiers]

http://metalworking.com/DropBox/_1999_retired_files/

I may have the 703 manual also. I think what I have covers two versions, one fully loaded and one somewhat stripped-down (no threading).

[John Foster]

J - Thanks, aadocs part 2 had the breakdown. The part number is a little hard to see but looks like C3311 (or 32 or 35). I doubt any of those castings are still available but having the right part number would help. Would you check your 703 parts list and double check it for me? The number I need is just below A3131 and is the ring gear casting where a normal bull gear would be.
I'm still looking at it tosee if I can make one. It going to be tough. Thanks, John

[J Tiers]

OK, will take a look. Might have to wait, I won't be near the shop and files for a week starting very soon.

The good news is that there is a bigger shop with more goodies where I am going to be

[roberlt]

John,
The part # you need is C-3511 "internal gear drum-back gear" According to my 1952 price list cost $1.50 Has not been avalable for at least 20 years.
Yahoo has a group for this lathe AA_109_USERS_GROUP they might be able to help.
They have helped me in the past

Rob

[John Foster]

Rob, thanks for conformation on part number. I really don't expect to find one but you never know. I doubt the lathe is worth my making a new one but it has been fun figuring out how this neat "back gear" worked. All the gears appear to be 24 DP but also are 20° pressure angle and that includes the change gears and gear train. I have a set of cutters for 24 DP but they are for 14 & 1/2° pressure angle! Don't want to buy a 20°set just just for this project. I have never had to make an internal gear so that would be a nice challenge and learning experience.
All of the change gears are missing plus one planetary gear is shot and one in the gear train has a tooth missing, so lots of work and time to bring this nice little machine back to life. Thanks again, John