Nomenclature and Underneath Drive Qs

[kcoffield]

I’ve been acquainting myself with the my 12” Craftsman lathes, have a location picked out in my shop, and have been doing some thinking on building a bench for it. I’ve also been doing some reading and comparisons as the underneath drive cabinet versions seem to package up nicely. It seems all of those cabinet models were being referred to as “Craftsman Commercial”.

Question 1: Does “Craftsman Commercial” refer to a specific set of features, upgrades, and/or model changes or is it just marketing? I ask because I see the cabinet models were not consistently referred to in that manner in the manuals.

I took a cursory look at the feasibility of such a conversion of my older horizontal drive 42” bench model and quickly discovered my headstock has no provision for bottom drive and the newer head stocks that do also house the back gears under the spindle so I discarded the idea and decided to stick with what I have. Then a local fella mentions he has a cabinet with headstock and bed, but everything else is gone, and I mean everything…….no carriage, tail stock, lead screw, and no gear train of any kind behind the headstock……but the spindle, back gears/engagement mechanism, and everything between the bearings is there, and so is the entire drive mechanism in the cabinet……..so that got me back on the subject of the possible conversion to underneath drive. This looks like it could become an (expensive) scavenger hunt and rabbit hole so thought I’d ask the experts if I’ve got it right.

I was hoping I’d just hang the gear train from the back of my older horizontal drive headstock on the new under drive version, and mount it on my existing bed, but it does not look to be that straight forward. At minimum, the reverse tumbler arm is different to accommodate the detent position in the newer style headstock, and possibly the gear train, banjo, etc.

Question 2: Is the rest of the gear train unique to the newer model headstock too?....and if it is, even if I’m able to collect those parts am I going to have difficulty interfacing with my existing lead screw? Will any of it interchange?

I did some downloads of manuals and illustrated parts references but the newer manuals in the Clausing era seem to have an entirely different part numbering system, so not much help there.

There also seem to be a number of different versions of end covers, and a unique set for underneath drives, with maybe even several variations within cabinet models.

I don’t know what kind of shape the bed is in on this local cabinet unit, but in my reading, I also found some discussion that said “Craftsman Commercial” beds had ½” thick ways while earlier versions were 3/8”. Is this so? It seems this would be no problem for the tail stock and the clamp could accommodate 1/8” difference in way thickness, but it may require some different shimming on the underside of the saddle/carriage.

Question 3: Will the carriage and tail stock assemblies from an early 12” Craftsman lathe interchange with a “Craftsman Commercial” or later version bed (if there is such a thing?). Is the rack, and are all the other interface dimensions the same?

Thanks in advance for your replies.

Best,
Kelly

 

[wa5cab]

1. "Craftsman Commercial" was part advertising hype and part based on improvements. The 1/2" bed lathes came out in late 1957. The cabinet variant was added to the line in 1958 or 59. In mid 1966, the three final changes were made, consisting of adding the slip clutch to the QCGB, adding the lever operated cross feed, and changing the right lead-screw bearing from a single casting designed to break and let the lead screw disengage from the gearbox in a crash to a sturdier one with roller thrust bearings with the lead screw and longitudinal or cross feed drive protected in a crash by the slip clutch. The Craftsman Commercial badge was not added by Sears until about mid 1971. There is no other difference between ones with it and ones without but made after mid-1966, One could say that Sears was just late in adding the Commercial badge.

2. Yes and No. Most of the internal parts were the same from around 1940 on. Probably around 75% if the parts in the 3996 or 101.28990 are the same as those in the TH54 or 101.07403. The main differences are of the major castings such as headstock and carriage. All that I think that you would have to do to mount your TH42 on the under drive cabinet would be to pull the spindle and exchange the 4-groove spindle cone pulley for the 2-groove under-drive pulley, use two shorter spindle belts on the latter, weld up the 4 existing bed leg mounting holes and cut four new ones. You would have to do some machining on the bottom of the headstock casting to clear the belts but the 2-groove spindle pulley is pretty small and the same diameter as the pulley underneath. The same is probably true of any of the early 12" but you did not say what model your 12" machines are.

3. No, maybe and yes. The early carriages fit a 3/8" thick bed. The bed lock would just require a new clamp. And you might be able to make special offset clamping bars to fit. And the rack is the same part. But it would be mounted 1/8" lower and although I guess that you could slot the mounting holes for the rack drive gear box, I don't know whether the gear on the back end of the hand-wheel shaft would still mesh. On the tailstock,, I don't have a 10" or early 12" bed to measure the way width and distance between front and rear ways. They are probably the same and you have or will have both to measure. You might only have to use a clamping bolt that's 1/4" longer. Late Edit - The bottom of the 10D-6 Base for the tailstock on the 10D, 10E and 10F.and on the equivalent 12" and the 2" tall L6-6A used on the equivalent 12" lathes for the Tailstock Turret and Lever Operated Tailstock is the same as on the 050-035 Base used on the 12" machines made after 1957. So mounting any of the early tailstocks on the late bed would only require a longer clamp bolt and probably adjusting the gib.

 

[kcoffield]

Thanks much wa5cab.

1. "Craftsman Commercial" was part advertising hype and part based on improvements. The 1/2" bed lathes came out in late 1957. The cabinet variant was added to the line in 1958 or 59. In mid 1966, the three final changes were made, consisting of adding the slip clutch to the QCGB, adding the lever operated cross feed, and changing the right lead-screw bearing from a single casting designed to break and let the lead screw disengage from the gearbox in a crash to a sturdier one with roller thrust bearings with the lead screw and longitudinal or cross feed drive protected in a crash by the slip clutch. The Craftsman Commercial badge was not added by Sears until about mid 1971. There is no other difference between ones with it and ones without but made after mid-1966, One could say that Sears was just late in adding the Commercial badge.

This good to know. There also seem to be a mind numbing number of variants to the end covers. Not very material to lathe operation but if you're trying to swap.......

2. Yes and No. Most of the internal parts were the same from around 1940 on. Probably around 75% if the parts in the 3996 or 101.28990 are the same as those in the TH54 or 101.07403. The main differences are of the major castings such as headstock and carriage. All that I think that you would have to do to mount your TH42 on the under drive cabinet would be to pull the spindle and exchange the 4-groove spindle cone pulley for the 2-groove under-drive pulley, use two shorter spindle belts on the latter, weld up the 4 existing bed leg mounting holes and cut four new ones. You might have to do some minor machining on the bottom of the headstock casting to clear the belts but the 2-groove spindle pulley is pretty small and the same diameter as the pulley underneath. The same is probably true of any of the early 12" but you did not say what model your 12" machines are.

Mine are mid 1940s vintage 12s. I honestly don't see how the headstocks could be converted because they narrow at the base and you'd never get the back gear under the spindle even if you had the ambition. The back gears look the same but I believe the eccentric an mechanism are also different, and as I mentioned, pretty sure the reverse tumbler too. If the cost of the cabinet with head stock is in the go zone, I may give it a whirl and report back.

3. No, maybe and yes. The early carriages fit a 3/8" thick bed. The bed lock would just require a new clamp. And you might be able to make special offset clamping bars to fit. And the rack is the same part. But it would be mounted 1/8" lower and although I guess that you could slot the mounting holes for the rack drive gear box, I don't know whether the gear on the back end of the hand wheel shaft would still mesh. On the tailstock, I don't have a 10" or early 12" bed to measure the way width and distance between front and rear ways. They are probably the same and you have or will have both to measure. You might only have to use a clamping bolt that's 1/4" longer.

Just thought I'd ask because I see beds advertised for sale all over the place but none of them ever seem to mention the thickness of the ways, and if it was a factor, seems like it would be more commonly discussed. If I get to the other lathe, I'll measure things up and report back.

Thanks again,
Kelly

 

[wa5cab]

Well, anyone who thinks that the bed way thickness doesn't matter doesn't know how the machines work. Unfortunately, that means most eBay or CL sellers. I wouldn't personally even think of trying to use a late 1/2" bed under an early headstock and carriage. Also, I cannot think of any valid reason to try to put the back gears on the rear of a 10" or early 12" underneath the spindle. They work fine as is. As to whether or not it would be practical to convert a 10" to under drive, I don't know. Unfortunately, none of the available documents can answer that question. And I don't have a 10" or early 12" headstock available to look at. I am pretty sure that it would require some machining.

 

[kcoffield]

Well, anyone who thinks that the bed way thickness doesn't matter doesn't know how the machines work. Unfortunately, that means most eBay or CL sellers. I wouldn't personally even think of trying to use a late 1/2" bed under an early headstock and carriage.

Just to be clear, I wasn't suggesting it didn't matter, quite the contrary. Beyond that I was merely observing it never seems to be noted in any way in related parts being offered for sale (other than the occasional reference to Craftsman Commercial), and there are many, so buyer beware and know what you are buying...........thus my questions here.

Also, I cannot think of any valid reason to try to put the back gears on the rear of a 10" or early 12" underneath the spindle. They work fine as is. As to whether or not it would be practical to convert a 10" to under drive, I don't know. Unfortunately, none of the available documents can answer that question. And I don't have a 10" or early 12" headstock available to look at. I am pretty sure that it would require some machining.

10"? Never mentioned and don't know anything about those. I'm not an Atlas/Craftsman aficionado, just a guy that inherited two, mid-1940s vintage, 12" Craftsman lathes a couple months ago. I'm trying to become more knowledgeable about them and get one set up to meet as much of my needs as possible.....and fit my available space. Under drive would package up nicely for the latter. I'm not married to the idea of under drive conversion but still have an open mind about the possibility. Perhaps you might consider doing the same and bear with me on that? If not, that's fine and I do appreciate your weighing in. Just to tie the threads together in the event I do pursue such a conversion my intro and info on the lathes is here......

New Caretaker of Two 12” Craftsman Lathes

Hi all, first post here. I’m the new caretaker of two 12” Craftsman lathes, one with a 42” bed and the other 54”. Though they recently came into my possession they are well known to me. The 42 is model 101.07403 number SN 16014 and the 54 is model 101.07403 SN 22500. The only place I’ve found...

www.hobby-machinist.com

Best,
Kelly

 

[Aaron_W]

I have seen an Atlas / Craftsman 6" lathe set up with an under drive motor. As far as I know they were never offered that way, so must have been an aftermarket or DIY conversion, so I expect with some creativity it would probably be possible to do the same with the larger 10 and 12" Atlas / Craftsman lathes. It wouldn't be the same as the cabinet models, but would give you most of the benefits.

Unfortunately I didn't think to save any of the photos of the drive arrangement on that 6" lathe.

 

[wa5cab]

I think that I recall seeing the (or an) under-drive 6" but don't recall the details except that I am almost certain that it was accomplished using the cone pulley still mounted on the spindle. Which isn't how Atlas did it on the late 12".

Some people seem to call both Craftsman badged versions of the late 12" "Commercial" or "Craftsman Commercial" even though the pieces may have actually come from one of the Atlas variants. And even though Sears, as I reported yesterday, did not introduce the actual badge until about 1972.

However, I learned many years ago that too many eBay sellers are clueless and don't properly describe what they are selling. When in doubt, ask questions and/or ask for additional photos, etc. That applies to anything, not just Atlas lathes and parts.

 

[kcoffield]

I have seen an Atlas / Craftsman 6" lathe set up with an under drive motor. As far as I know they were never offered that way, so must have been an aftermarket or DIY conversion,

I think that I recall seeing the (or an) under-drive 6" but don't recall the details except that I am almost certain that it was accomplished using the cone pulley still mounted on the spindle. Which isn't how Atlas did it on the late 12".

I don't know much about the 6" Atlas lathes but just looking at pictures on the auction sites, bottom drive looks like no problem for them, but I think they still hang the back gears.....well on the back as opposed to under the spindle like on the 12". Also I don't know how big or if there is a sufficient gap in the bed under the headstock. Here's a picture of the 6" headstock and it looks like the wide open spaces to me but for all I know there may be multiple versions of it too.

so I expect with some creativity it would probably be possible to do the same with the larger 10 and 12" Atlas / Craftsman lathes. It wouldn't be the same as the cabinet models, but would give you most of the benefits

I think I've got the rear to under drive swap figured out for my 12", and after watching the necessary parts on auction sites for the last three months, have identified acquired or in the process of acquiring all the necessary parts at economically sensible prices, and should have them in hand by the end of next week. I'll start a separate thread on the project in the near future.

Best,
Kelly

 

[wa5cab]

WRT the 6" or 618, the same headstock casting was used on the Atlas 618 from start to finish. The 6" and for that matter the 10" headstock is not tall enough to mount the back gears under the spindle. The 12" is (obviously) but at the time that the original 12" came out in 1936, for cost reasons it needed to use as many of the 10" parts as possible. So only the headstock castings, compound upper slide and tailstock were different. And making the tailstock different instead of the tailstock base was a tactical error that they lived to regret a short time later.

 

[Aaron_W]

This is not the 6" Atlas that I was thinking of, but I saw this one on CL today and it seems like an interesting option rather than putting the motor behind the lathe.