Craftsman 101.07403 Feed Rate Question
I found the below year and ½ old thread & gained much valuable information on gearing & speeds & feeds for the 101.07403 12” Craftsman lathe.
https://groups.io/g/atlas-craftsman/topic/101_07403/30186073?p=
I thought that my question would be better as a standalone, so here goes……..
This question is about turning & facing operations. NOT about threading! I have a Craftsman 101.07403 12” lathe. No Quick Change gear box. I have extra gears & change gears manually as needed. As you can see from the image of the machine’s Threading Chart, the slowest FEED rate indicated on the chart is .0024.
The question:
Is this the slowest feed rate possible on this lathe? Is there any other combination of gears that might slow the feed rate down further (Even if I have to obtain additional gears)?
I have figured out slower combinations on paper. But, when I attempt to implement them, the gears do not mesh correctly because of the parameters of the banjo design.
Thanks!
--Bruce Varner
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
I found the below year and ½ old thread & gained much valuable information on gearing & speeds & feeds for the 101.07403 12” Craftsman lathe.
https://groups.io/g/atlas-craftsman/topic/101_07403/30186073?p=
I thought that my question would be better as a standalone, so here goes……..
This question is about turning & facing operations. NOT about threading! I have a Craftsman 101.07403 12” lathe. No Quick Change gear box. I have extra gears & change gears manually as needed. As you can see from the image of the machine’s Threading Chart, the slowest FEED rate indicated on the chart is .0024.
The question:
Is this the slowest feed rate possible on this lathe? Is there any other combination of gears that might slow the feed rate down further (Even if I have to obtain additional gears)?
I have figured out slower combinations on paper. But, when I attempt to implement them, the gears do not mesh correctly because of the parameters of the banjo design.
Thanks!
--Bruce Varner
Position A: 20 tooth gear near, 40 far
Position B: 50 near, 24 far
Position C: no gears in this position
Position D: spacer near, 64 far
Compound gear: 16 tooth
Left Hand Lever position E
Right Hand Lever position 9
where ‘N’ is gear next to the quadrant (banjo)
and ‘F’ is gear or spacer away from the quadrant.
FOR THOSE WITH QUICK CHANGE GEAR BOXES The lowest feed rate that the Atlas engineers figured out is .001” per revolution using change gears. There is an ‘Atlas Quick Change Attachment Hand Book’ that lists change gear setups from 0.8” to 0.001”. That file may be in the Group files. I have a pdf of it on my home computer. Here is the change gear setup for 0.001” feed:
Position A: 20 tooth gear near, 40 far
Position B: 50 near, 24 far
Position C: no gears in this position
Position D: spacer near, 64 far
Compound gear: 16 tooth
Left Hand Lever position E
Right Hand Lever position 9
where ‘N’ is gear next to the quadrant (banjo)
and ‘F’ is gear or spacer away from the quadrant.
That manual is already in Files on groups.io. It is the next to last entry under “28 Manuals, Atlas or Atlas-Craftsman Lathe Accessories”. Also in that same folder are the installation instructions for the 1500, 1570 and 6800 versions of the 10” QCGB’s.
Robert Downs
Sent: Monday, October 26, 2020 11:14
To: atlas-craftsman@groups.io
Subject: Re: [atlas-craftsman IO] Craftsman 101.07403 Feed Rate Question
Bruce,
Here is a complete 1947 Quick Change Handbook. I couldn't scan any lower DPI or it was illegible.
Steven H is correct about .001" being the slowest rate.
Mike
No problem. What seems logical after the fact often isn’t before it. J
Robert Downs
Sent: Monday, October 26, 2020 14:36
To: atlas-craftsman@groups.io
Subject: Re: [atlas-craftsman IO] Craftsman 101.07403 Feed Rate Question
Robert,
Sorry, I looked and didn't see one.
Feel free to delete as needed.
Mike
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
My question was the slowest gearing possible with manual change gears...
Bruce Varner
This is a partial correction to Bill’second paragraph, first sentence. In any given year, the 10” and 12” used the same change gears.
The 10” up through the 10D (including original 10 and the 10A, 10B, 10C or 10E if you went back and bought the thread cutting kit, had a change gear set with part numbers of the format 9-101-NN, where the “NN”was the gear tooth count. These gears had a 3/8” wide or thick hub and a 3/8” wide face. The Craftsman 12” models 101.07360, 101.07361, 101.07380, 101.07381, 101.07400 and 101.07401 had the same gears and used or could use the same threading table. This gear set went up through 96 tooth
The Atlas 10F and the Craftsman 12” models 101.07362, 101.07363, 101.07382, 101.07383, 101.07402, 101.07403 and all later 12” change gear models used change gears with part numbers of the format 9-101-NNA and had the same 3/8” face but had a 1/2” thick hub. All of these models used or could use the same threading table. This gear set only went up to 64T. . Note that the “A” suffix gears are also used in all of the Atlas and Atlas-Craftsman originally equipped QCGB models to couple the spindle to the GB.
The MOLO’s that all just say Copyright 1937 and that were printed over the years between 1937 and 1953 inclusive have several slightly different versions of Chapter 7 Threading, Threading Supplement, or Thread Cutting Chapters, some bound in and some loose (and more often than not, missing). For finer feeds, of what is recorded in the many different editions of the MOLO, with the original with 96T max set of gears, you can go down to 0.0018” feed but it requires making four special parts (two special hollow studs, a special hollow keyed bushing, and a special key). Without making special parts (but it does require an extra 20T gear) the apparent limit is 0.0027”. This is for 10E and earlier 10” and the early 12”.
With the later “A” suffix set of gears, and with two extra 20T gears, the limit is 0.00157”/Rev. This is for the change gear 10F and for all of the later 12” change-gear models with 3/8” or 1/2” bed.
Robert Downs
Sent: Tuesday, October 27, 2020 15:28
To: atlas-craftsman@groups.io
Subject: Re: [atlas-craftsman IO] Craftsman 101.07403 Feed Rate Question
***
The 10F lathes, IIRC, use a 3/8" thick change gear, where the 12" lathes use a 1/2" gear,
***
William R. Meyers, MSgt, USAF(Ret.)
Bruce, I think it's possible to use the 96t gear with the 3/8" hub on the later models (10F & Craftsman 12") that used 1/2" hub gears:
I wrote the following BEFORE reading Robert's detailed reply, but I'm glad i saw that because I was not aware of the difference in the hub width of the earlier and later models.The 96t gear I refer to below indeed has a 3/8" hub.
Bruce,
In response to this:
"My question was the slowest gearing possible with manual change gears..."
Atlas made a 96-tooth gear. There is some way of mounting this in the gear train so that it reduces all of the feed rates to 1/2 what they would otherwise be.
Years ago I met someone who had his own 10F set up with one of these large 96t gears. When I finally got my own 10F I searched for and eventually got one. Before I had occasion to use it, or to even ponder where it would fit in the setup, a late-model 12" Craftsman came my way and I sold the 10F. I still have that (huge) 96t gear, but no use for it.
I wish I could explain how to do the setup. When I saw the setup with the 96t gear it seemed obvious to me, but now, years later...
I vaguely recall that the large gear was mounted lower down, near the front of the machine. Was it perhaps actually mounted on the drive screw? That would make sense. If I had a 10F in front of me I could probably figure it out.
There's someone on eBay selling 3D-printed copies of these gears:
https://www.ebay.com/itm/NEW-ATLAS-CRAFTSMAN-9-10-12-Lathe-Change-Gear-96-Tooth-ABS/274215175835?hash=item3fd87f869b:g:GygAAOSwHwleJQ7Y
I have no use for mine. I'll happily sell it for about what I paid for it. I'm willing to send it for you to first test the setup. There must be some way to make shims or spacers for the missing hub width.
Kurt B.
Chicago
Is there any other combination of gears that might slow the feed rate down further (Even if I have to obtain additional gears)?
Hello Bruce Varner: I am a bit late to this party but in a nutshell if you have the change gear bracket pictured in the chart (L3-58M or L3-58) you included in your original post then you can achieve a feed rate of a little more than .0010805 by using three 96-tooth change gears. I have accomplished this on my Craftsman 12 x 24, c. 1935
In the attached photos I used three Atlas 96-tooth gears, part number 9-101-96. These are all 3/8" thick. I believe your lathe uses suffix A gears which are 1/2" thick at the hub so the Atlas 96-tooth gears will not fit properly, at least not directly. You have some choices:
A) Procure an extra set of gears that are all 3/8" thick at the hub along with 9-70 bushings and 9-73 sleeves that are approx. 3/4" long so you can use all 3/8" thick gears.
B) Procure an extra set of gears that have Suffix A then face off the hubs taking about 1/16" off each side, and shortening a set of 9-70A bushings and 9-73A sleeves to fit.
C) Procure three 96-tooth cast iron gears from Boston Gear, part number GB96A, available through a number of vendors. Be careful searching for lowest price. It took me several months to acquire a set of these gears at "discount" prices and even at that they were costly, close to $100 each.
D) Make, or have made, three 96-tooth gears via 3D printing process. For your lathe they should be 1/2" thick at the hubs, 3/8" thick at the rim.
If you choose option C or D you will benefit from facing off the rim of the gears to be 3/* thick at the teeth while still 1/2" thick at the hub. This will reduce interference at the rim which can be troublesome or at the very least generate a lot of noise as the gears rub against one another.
Enjoy!
Raymond
Robert,The 10” up through the 10D (including original 10 and the 10A, 10B, 10C or 10E...had a change gear set with part numbers of the format 9-101-NN... This gear set went up through 96 tooth
Is there a threading chart readily accessible that shows the setup for those early models with the 96t gear?
Kurt B.
If you choose option C or D you will benefit from facing off the rim of the gears to be 3/* thick at the teeth while still 1/2" thick at the hub.Correction to typo error: If you choose option C or D you will benefit from facing off the rim of the gears to be 3/8" thick at the teeth while still 1/2" thick at the hub.
Raymond