Rigidity in an Atlas 10F lathe -HELP-

If you could post a pic of the steel finish that might be helpful. When cutting, how much material is sticking out of the chuck? If more that 3 times the dia. the end should be supported. Are you sure you are on center with the tool? if you take a facing cut does it leave a nub in the center? The spindle adjustment might have loosened. put an indicator on the chuck and try to move it. Trying HSS is a good move, but the insert type you have should work okay. I have a 12" 3/4hp Atlas and CCMT insert tooling works fine on steel as long as the nose radius is not too large. as others have said uplift on the carriage could be the culprit. I would test it with an indicator. I don't have any experience with 5C collet chucks. but it looks to me that there is an awful lot stick out with just the chuck and that may be a source of flex. Just for ****z and giggles try a 3 or 4 jaw chuck. Once you get this bug fixed though I think you will be very happy with the lathe.
 
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Derek, that is a beautiful restoration you did. She looks better than new!

I agree with everyone else that HSS would be a better idea than inserted carbide. You are currently using a 1/2 SCLCR tool with a worn insert (see the flank wear on the side of the insert - that insert is shot). If you choose to use it, use a new one with the smallest nose radius you can find and orient the tool shank perpendicular to the work piece. You should also consider using an CCGT AK insert. While it is intended for use with Aluminum, it will also cut steel just fine. The AK insert has a very positive rake that will reduce cutting forces significantly and may help more than you might think.

I also agree with using a plinth. It will help reduce flexion in your set up.

I do not agree with having to mount the lathe flat on a surface. If the surface is solid then mounting it on leveling studs will be fine. My Emco Super 11 is heavier than your lathe is and is mounted on two studs per end. It is rigid and solid, with zero issues in use. Please reconsider the use of shims - that is misery and you will hate it every single time you level the lathe!

You have gotten some really solid advice in the posts above, especially about using HSS. Your lathe has great potential and HSS will wake it up. If you need help, post up in the Model Tools thread and we'll give you a hand.
 
mikey said:
Derek, that is a beautiful restoration you did. She looks better than new!

I agree with everyone else that HSS would be a better idea than inserted carbide. You are currently using a 1/2 SCLCR tool with a worn insert (see the flank wear on the side of the insert - that insert is shot). If you choose to use it, use a new one with the smallest nose radius you can find and orient the tool shank perpendicular to the work piece. You should also consider using an CCGT AK insert. While it is intended for use with Aluminum, it will also cut steel just fine. The AK insert has a very positive rake that will reduce cutting forces significantly and may help more than you might think.

I also agree with using a plinth. It will help reduce flexion in your set up.

I do not agree with having to mount the lathe flat on a surface. If the surface is solid then mounting it on leveling studs will be fine. My Emco Super 11 is heavier than your lathe is and is mounted on two studs per end. It is rigid and solid, with zero issues in use. Please reconsider the use of shims - that is misery and you will hate it every single time you level the lathe!

You have gotten some really solid advice in the posts above, especially about using HSS. Your lathe has great potential and HSS will wake it up. If you need help, post up in the Model Tools thread and we'll give you a hand.
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Thanks for your comments. I hope that I can get things figured out! I will send that insert packing. I am going to step away from carbide and focus on HSS until I get the lathe “under control”. I am going to try to support it differently, but maintain the posts, a hybrid solution so-to-speak. I will report back to the thread next week with my progress, success and/or failure.

Cheers

Derek


Sent from my iPad using Tapatalk
 
Moderatemixed said:
When I put a piece of stock into the chuck, I look at the material, the feed, the speed, and once I start turning I have on one occasion gotten nice chips (in mild steel) but in most cases I get a surface finish rivaled by a teenagers “zit covered” face and vibrations that my wife says put ripples in her coffee 2 floors up. (I’m in the basement). Even with aluminum the lathe often vibrates like an ultrasonic cleaner!
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[emphasis added]

Even aluminum? It is not some special aircraft-grade aluminum, is it? What about brass? I would suggest you get the lathe working with softer, easier-to-machine metals and then play with some steel. Even then, start with some known, easy-to-machine steel like 12L14. Early on, I tried to turn some random mystery metal and it wouldn't cut at all. I'm now pretty sure it was hardened steel and needed to be annealed. As a newb, it just seemed to be laughing at me!

As so many others have said, HSS cutters ought to help. In all deference to Mikey's thread on sharpening, I found the following web page (and one page pdf summary) to be clear and easy to follow:


Probably it is fine, but I'm not familiar with that style of QCTP. To be sure though...the tool needs to be secure in the holder; the holder has to be rigidly mounted to the tool post and the tool post must be held securely to the compound. Have you gone through these interfaces? Perhaps, say, a nut is hitting the end of threads before really clamping down?

Craig
 
One more quick thing. On the attached photo it looks like your QCTP is not centered on the compound. Try moving it near the center. Maybe won't help with the issue, but it's worth a try.
Mike

keQCTP .JPG
 
Derek,
That really is a beautiful lathe. You did one fine job. I have a similar Atlas lathe, although not nearly as good looking. I am generally pleased with the surface finishes that it gives me. I'm just a beginner hobbyist, so I don't know much, but here are some things I noted:
  • I work mostly with aluminum alloys, brass, 12L14, stainless 303 and Delrin - the easy stuff.
  • I use hand ground HSS tooling. The sharpness and the nose radius are critical to surface finish. I have not had much luck with carbide insert tooling, although my experience is very limited.
  • My chucks are short - so I'm working closer to the spindle.
  • I lock the gibs on all axes except the one I need to move for a particular operation.
  • I had significant pulley vibration. The old Zamac motor and small countershaft pulleys were wobbling slightly (does Zamac cold flow?). I turned new pulleys from 6061, and they run true. I still get some vibration from the big countershaft pulley. I purchased a second one on eBay but it wobbled about the same as the original. That pulley is too big for me to make.
  • The motor configuration with it hung from the bed is just a bad design. I have put rubber shock mounts on the motor, and they help some with vibration, but I still feel the motor vibration on the bed.
  • Replacing the belts helped some with vibration. The original circa 1954 belts were stiff.
 
shadetreedad said:
Moderatemixed,

First off, that is a beautiful machine. You'll have a lifetime of fun/satisfaction with it.

Regarding the stand offs, I know there are machinists who will disagree but I three pointed my Atlas lathe with 2.5” risers on the headstock end and a single center point on the tailstock. Since I move my lathe around in a small shop on a bench with wheels this allows the lathe to have a “natural” levelness. I can take .025” cuts in steel with no issues. In aluminum .050” easily. I suppose if I took much deeper cuts there could be a problem with bed flex, but I haven't noticed any. I do use razor sharp 3/8” or 1/2” HSS bits. An AXA tool holder is perfect for that 10” lathe. Also, a singe piece plinth on the cross slide (replacing the compound) will make for a much more rigid setup. I made mine out of round stock aluminum. Same height as the compound.

Mike
Click to expand...
I ended up supporting my Atlas 10F in the same way @Moderatemixed did here. After leveling and testing for any twist (which I did have after mounting this way) I have nice even, no taper cuts. And I'm taking heavy cuts in steel, .020-.030 doesn't seem to bother it - surface finish is questionable but hey, its "roughing" with an Atlas at the DOC.
 
Have you inspected the compound slide carefully? I have had two of this crack in the t-slot area. I have since switched to an all steel version, much better. Also agree on the CCGT inserts made for aluminum, they work really well on most metals
 
That is a hideous amount of overhang on that tiny compound.

That compound was designed for an old-school lantern style tool post with the tip of the tool bit within 1-1.5" of the center for the T slot.

You're looking at 3"+ of overhang, not to mention everything else that has been mentioned.
 
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