Beefing up a Craftsman 6" and a "chop and channel" I'll dare to ask the questions

Crank

Crank

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In the midst of overhauling my Takisawa 14x32, one of the guys from the RC boat club mentioned a Craftsman 6" lathe he wanted to sell. In typical fashion, I piped up I was interested and it followed me home. I grabbed it because it shows virtually no wear and the paint is in decent shape. It's a later production with the square head, probably late 1960's or so. IIRC it is the #101.21200, 6"X18". I have had several of the earlier rounded versions over the years and they were just novelties that I would fix up and re-home them.

Here is my first question, now that I have more room, I was considering a small, high end, precision lathe to accompany the Takisawa. However, this Craftsman is sitting in my shop and didn't cost me an arm and a leg. All around the interwebs you will find people taking their little HF import mini lathes and upgrading them to levels never expected, to wind up some fairly precise equipment. On the other hand, there isn't a peep about doing the same to the thousands of Craftsman lathes that exist. Over and over, you see someone get a scruffy old Atlas/Craftsman and they fix them up and are satisfied with that. So my thought is, what could be done to stiffen one up and improve the accuracy even more?

My second question is sure to be regarded by some as heresy. At one time, the earlier Craftsman was offered in a 612 model, rather than the garden variety 618. As you would surmise, this was a tiny little guy with 12" between centers. It seems to be a rather desirable variant and well appreciated by their owners. I am thinking about surgery on the bed to create a more modern variant, either by relocating the foot or creating a cantilever design. Before anyone cries foul, remember the sheer number of these that still exist and the 6"X18" is far from a high dollar collectors item. I definitely have no need for the additional distance between centers and it would make for a unique oddity that would fluster someone :confused:.

So has anyone done either of these modifications, or have a link to something similar? I'm leaning towards adding higher precision bearings, stiffening the headstock and reducing tolerances wherever possible. Is this sensible?, not likely, but we all love a challenge and this intrigues me. Please feel free to share your thoughts, or if you can't stand the thought of it happening and want to trade me some wildly expensive European lathe so that no harm comes to the Craftsman:D, just say so.

Mark
 
I don't recall ever seeing or hearing of anyone shortening the bed on any of the seven Atlas or Craftsman/Atlas 6" lathes. And I don't have any of the 6" beds on hand to look at how the casting is made to see what the consequences of shorting the bed to 30" would be.

The Craftsman 101.21200 is the same except for badge as the Atlas 3950. They have ball type spindle bearings, and were made from 1973 until 1977. In 1977, the headstock casting and spindle were changed and the spindle bearings were changed back to Timken. Sears did not sell this model, and it was produced up through early 1981 as the Atlas or Clausing 10100. You could possibly swap the headstock on your 101.20122 to one from an Atlas 10100. Just make sure that the casting is cast iron. At some unknown point but probably early to mid 1980, Clausing changed the headstock casting to Zamak. It was much too light and those are prone to cracking and should be avoided. A few other changes were also made mainly as cost cutting means, and those should mostly be avoided. But if you stick with all of the rest of the 101.21200 parts, you will avoid them.
 
wa5cab,
If I understand correctly, you mean the bearings of the 101.21200 were a conventional ball bearing, as opposed to a tapered roller? If so, I could see that being a bit of a hang up for getting the tolerances reduced. That is some great info and I appreciate your input. Shortening the bed won't be complex, just a matter of careful cutting and milling to keep everything from getting out of parallel. This is still in the thinking stage, but I figured it could be fun to discuss and information such as you have provided is exceptional.
Thanks

Mark
 
Mark,

Yes, the spindle bearings in the 101.21200 and the identical 3950 are ball bearings.

On shortening beds, I have always felt that it should only be done in certain increments, so that whichever end you shorten will look exactly the same as it did before in terms of the size and location of the webs relative to the new end. With most of the Atlas produced beds, that means increments of 6". And don't forget that you will also have to shorten the lead screw and the carriage traverse rack. On the rack, this would involve drilling and reaming one new taper pin hole. On the lead screw, after cutting, you will have to machine the cut-off end so that it looks like it did originally. Regardless of what lathe you use to do the turning, you will probably have to rig up an anti-whip support bearing to prevent the other end of the screw from whipping around and bending itself.
 
If it was me I'd put my money and effort into adaptive tooling for the Takisawa rather than trying to beef up a second smaller lathe.

If you Tool the lathe up for 5C collets, there are cheap and expensive ways to do that, you can get a small chuck with a 5C mount integrated into it.

You can get a ER32 holder (I think that is the one) with real small rubber flex style inserts for about $100.

Then I'm sure you could get a small miniature chuck and just chuck it up in the Takisawa's chuck.

You can make a adapter holder for cutting bits less than ¼" square, etc.

I would think the Takisawa should hold .001 or better on diameter and whatever your measuring devices are accurate to on length.
 
Dave,

I know nothing about Takisawa's including where they are made or what size they are. But I have always disagreed with people who claim that no lathe is ever too large to handle small parts. My favorite example was a 60" by I forget but it was more than 240" that I used a couple of times to machine test defects into 48" X60 line pipe.

One other comment is that ER style collets are all-metal, not rubber-flex. They just look a little like them.
 
Doing as you think will be a bunch of effort to make a lathe worth much less even if perfect.

Size matters and length is handy where short is just that.

Instead clean and tune up your example for resale and you can get decent money for it that can be used for buying next one...

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
Dave and tq60,
Excellent replies and both very valid. I plan to add a 5C collet chuck and other small workholding assets to the Takisawa no matter what. I don't plan on any parts for the space program, but I will expect tolerance to be capable of better than .001 on the Takisawa. The Craftsman is a lark and as I stated, I had already planned to get another lathe for those little oddball jobs that pop up and take a couple of minutes to do and don't need the bigger lathe fired up. Time and effort are not the reason I asked the questions, but rather, has anyone else done it. As for "decent money", when these turn up, they max out at about $600 in this area and there is no shortage of them, so not a high ticket item by any stretch. Length is certainly not an issue, I even considered a construction without a tail stock, since this lathe would be for those short jobs that don't require one. I did spot a Rivett second operation lathe that might be a better starting point for modification since it is infinitely stouter to begin with and has a much better set up for the spindle.

wa5cab,
Thanks for your comment, you understand that sometimes just because it can, doesn't mean you want to use the bigger lathe. I could hunt jackrabbits with an elephant gun, but a .22 does the job just fine. I don't mind having more than one lathe, but the small one will be focused on minimal size and precision, not capacity. I'm not wealthy by any stretch, but I will spend money to have quality gear and the ability to apply the right tool for the job.

Sorry for the long delay, I started pecking out a reply last night on my phone and then the battery was threatening me with imminent demise, so I had to pick it back up this morning.
Thanks

Mark
 
I have what may be a similar lathe, Atlas by Clausing, model No. 3950 on a tag on the right end of the bed. The bed is very nearly 30 inches long, it's maybe 20 inches between centers. I have an ER40 collet chuck on the spindle and have very few mods otherwise. While it's not my only lathe (I have a small Ames Turret lathe) it gets most of my work. I don't intend or expect to do anything larger than it will handle and don't expect to need a bigger "Better" lathe. I've built a couple of extra banjos and can change the entire banjo and gears about as quickly as g gear setups. I don't have to sort out the right gears each time.
I'd hesitate long and hard before chopping the bed, I use the right end to store the tailstock on, and the wasted space between saddle and tailstock gets used when I move the saddle away to mike my work.
 
Tom,
Trust me, I know all about using extra space to keep putting more stuff on it, definitely one of my problems. In a nutshell, I am forever spoiled and won't be without a lathe that weighs as much as a small car, however, I am doing more small work on RC scale boats and very little with gunsmithing anymore, so my needs don't require me to have one size fits all. I am finding more times where I need to bore out a hole, reduce a diameter, make a flange or coupler on a part less than 1/2" in diameter with a moderate amount of precision. Most of these items will be supported adequately by the chuck to do the work. If I need to swing a barrel blank, cut a chamber, thread, take a large diameter and make it a small diameter really fast, the Takisawa will be standing by.

It seems so far, that what I posed for questions have not been done, or at least not shared openly. I'll probably hold off on any work, not because I might harm the machine, but because this one doesn't seem to lend itself to becoming what I have in mind without radically re-engineering it. I truly appreciate all of the comments and any more to follow, I think it's interesting to discuss topics like this because it makes you reassess what is normal or acceptable and question "why".

Mark
 
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