Ball turners specifically for Atlas 12"

[ARC-170]

Has anyone made or come across a ball turner for an Atlas/Craftsman 101.07403 lathe? I've seen lots of plans for ball turners, but the lathe I have doesn't leave much room for the tool, so this limits the ball diameter to less than 1.25". I'd like to see if there's something specific for these lathes.

The type I'd like to try and make is this one:

The cylindrical rotating part and the base plate have to be really thin (unlike the picture) to allow for turning anything bigger than about an inch in diameter. This doesn't seem like it will be abler to take the cutting forces, even with lighter cuts.

This one would probably work a little better, but I'm concerned about fabricating it. Specifically, getting the axle holes on the outer yoke piece concentric. They can't be drilled/reamed at the same time because the drill bit/reamer needs to be really long to go thru both holes at once. I'm sure I could get them close if I did them separately, but it seems even a few thousandths would be too much.
Also, I have lots of square tool bits and don't want to buy a a square broach and press to make the hole. I'm not sure I'm comfortable using a round bit (I like to grind bits using the tool rest and a round bit wants to spin). So that means making the C-shaped tool bit holder in two halves, or making the a slot for the bit and making the holes off center to line up with the center of the bit.


Anybody got any ideas, links, etc? I'd hate to reinvent the wheel. Thanks!

 

[Bi11Hudson]

There are several videos on "You-Tube" involving using a boring head as the cutter. The one I am pursuing involves mounting the boring head to the tool post. On a Craftsman 12X36(101.27440) with an AXA tool post. . . There are some more using a milling machine. I bought a head with MT-2 mount so I can experiment with an Atlas bench top machine as well. Like you, I need to make ball ends above a couple of inches.

I must apologize. . . I searched my "bookmarks" but it seems that I have deleted them after I built a set of plans. A version using the tailstock is located at [

] . I don't particularly recommend that one, but following links from there should reveal several different approaches.

The devices are not machine specific, they should work on most any machine. I am not aware of one that is specific to the Atlas/Craftsman machines. But probably wouldn't search for one in any case. Parts and attachments for the older machines seem to be built using gold. (My opinion only) I build most of my own. But then, I'm a cheap old buzzard.

I admit I'm not a machinist. And don't do machine work as a hobby. I am a model builder and adapt my machines to do what I do. That determines the choices I make for such attachments.

Edit Afterthought: When I approach a problem I usually like the solution to be usable for more than one function. The video above is indicative of such thoughts. One tool, two (or many) uses.
.

 

[benmychree]

The commercial ball turner that Holdridge makes does not have to be in absolutely perfect alignment; the bottom pivot is a center drilled hole in the yoke holding the cutting tool, with a setscrew threaded into the main frame to engage the tool yoke that is shaped on its end to match the center drilling, it looks just like a center drill, but without flutes cut into it. The upper pivot is a snug fit in the main frame and in the tool yoke and is secured in it by a split with a screw to tighten the split, there is nothing to do with up and down backlash in the assembly, only gravity and cutting forces. The tools are round, with a flat that the clamping screw bears on. If you want to use square bits, the Sturdy broaching service makes square hole sleeves that can be inserted in a reamed hole, also Holdridge sells replacement round bits for their attachment or they could be made from extra long center drills or HSS drill blanks. You should be able to find Holdridge online to see examples of their products.

 

[mattthemuppet2]

I built a boring head ball turner the same as Bill is doing. Works really nicely and to be honest gets used more on the lathe than the boring head does on the mill, which is kinda funny.

 

[Moderatemixed]

I have the Holdridge Radii Cutter 3-D. While I can’t really comment on how well it works as I am having my own set of issues with my lathe and rigidity (Atlas 10 F), I understand it to be a great tool. I bought it on Ebay and plan to use it in the coming weeks. Many guys make their own, and they work to varying degrees..... I just didn’t want “another project” or to have to fiddle with one that I made. I’m just starting in this hobby and my skills are at or about the kindergarten level of machining. I would have loved to have tried to make a radius cutter but I suspect it will be some time before I have the skill to fabricate something that intricate (to a level where it actually works). I got into the hobby because I love the precision, and I like to think that I could have made a radius cutter, but experience has tought me to crawl before I walk and so I chose to go the “buy it now” route. Good luck though, we’re all in this together.

Good luck.

Derek

Sent from my iPhone using Tapatalk

 

[ARC-170]

I found this one on this site via another Google search that was made by member @terry_g. It uses the boring bar attachment for a QCTP. I designed a similar one. Theoretically the one I designed will turn a 3" diameter ball. Anyone familiar with this design or see any issues with it?
I was going to make it out of aluminum (since I have the material), but should I go with steel?

Here's a link to the one I'm copying:

Lathe Ball Turner

Here are the ball turner plans i used for my ball turner. Pretty easy to make but may spurn a few more lathe projects Like a larger face plate, cross slide hole driller, so be prepared to spend a long winter indoors. The big ball in the last 2 pics is 3" in dia and was a joy to make on a small...

www.hobby-machinist.com

 

[wa5cab]

I don't know of one specifically made for either of the Atlas 12" model groups. But I have one for my 3996 that was made by Wettstein Tool. Model A1-248, it was made to fit the lantern style tool holder. Maximum ball diameter is 1-5/8". I got it from Bass Tool here in Houston several years ago. They also make a larger one but I don't know whether it would fit the 101.07403 or 3996 or not.

 

[ARC-170]

I'm going to make one like in post #6. All the ones that can be bought are way too expensive, even used. Besides, this looks like it will be fun to make. So, should I use aluminum or steel to make the parts?

 

[mattthemuppet2]

steel, you'll get a better finish as the cutter will be less prone to digging in.

 

[ARC-170]

I realized that this particular design will only do a half-round on the end, it will not do a full ball because there needs to be a third axis of movement that is perpendicular to the floor.
Theoretically it will do one, but practically it will not. The cutter needs to be able to move "up and down" (perpendicular to the floor) to be able to start "up" to make a light cut, then "down" into the part to make the ball.