couple of novice questions

Hello all: Without boring you all on my background, I have a Southbend Heavy 10 Lathe Model CL187A. Sadly, the previous owner used this for woodworking, so six months later I'm still cleaning sawdust out of it.

My first "real" project was making a stop nut for my old Craftsman 150 drill press. I couldn't find one, and it is a 5/8" nut with 12 TPI acme threads. I tried at first with steel, and real fast smartened up and went to aluminum. I'm done, and happy with it.. but some questions.

For internal threading on a relatively small diameter part, how do you keep the cuttings out of the threads you just cut? I'm using collets, and all the spiral cuttings are left in the part I am making. I ended up drilling it all the way thru, but then the shavings just end up at the end of the part inside the collet. And it seems like they want to grab the boring bar and damage my cuts.

Next question... 12 TPI has the feed going fast in my opinion. I'm going as slow as I can, but it is still fast and timing has to be right or the slide will crash into the headstock. But they didn't have VFD's 50 years ago?

I might put a VFD on this. Can someone save me from trying to measure the motor plate advise me what mount these use for the motor? It's a 1800 RPM 3/4 HP single phase motor manufactured 30 miles from where I grew up. (Schenectady NY) My lathe is a CL187A, which I guess is a "10 Heavy". If you dropped it on your toe you'd think it was heavy for sure.

Thank you in advance for your patience and help.

Oh yea... now I know why the military pays 3,000 bucks for a toilet seat. Even at minimum wage this nut would have cost a lot of money!!!

Wayne

Why not use the back gear for threading?

johansen said:

Why not use the back gear for threading?

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Ha. So don't laugh too hard please... And maybe I shouldn't post this because it makes people think I took the short bus to school... bottom line is I didn't know what the "back gear" is or did, other than lock the spindle from spinning. And... I've misplaced my "how to run a lathe" book... So I got up this morning, looked at the back gear assembly, and assumed something was wrong because the belt is always going to drive the upper pulley, turning that gear.... until I pulled that little pin out which let that drive gear spin. So thank you. I owe you a 200 dollar beer for saving me from buying a VFD and 3 phase motor... And my wife will like you because of that too.
Thank you!

Wayne

OTOH- I am pretty impressed a beginner successfully cut an internal 12TPI acme at 200+rpm!

Thumb up from me!

Unless the thread is an strange one and I don't have or can't get a tap for it, I generally don't use a single point tool to cut threads under 3/4" in diameter in the lathe. A tap is much easier to use for that. In the case of an Acme thread, I'd usually do a couple of passes with a single point tool and finish with a tap because the torque required to turn an Acme tap can be pretty high.

In answer to your question about the chips, if you run at slow speed using the back gears, the chips will generally just tumble out of the bore of the workpiece. If not, you can stop the lathe and brush them out with a small, cheap bristle brush. Running at high RPM will keep the chips in place and I can see how that might be a frustration. As suggested above, use the back gears for threading.

Huh?? Back gear has nothing to do with reverse...it simply gears things down approx 5:1 ratio.

wayneh said:

Ha. So don't laugh too hard please... And maybe I shouldn't post this because it makes people think I took the short bus to school... bottom line is I didn't know what the "back gear" is or did, other than lock the spindle from spinning. And... I've misplaced my "how to run a lathe" book... So I got up this morning, looked at the back gear assembly, and assumed something was wrong because the belt is always going to drive the upper pulley, turning that gear.... until I pulled that little pin out which let that drive gear spin. So thank you. I owe you a 200 dollar beer for saving me from buying a VFD and 3 phase motor... And my wife will like you because of that too.
Thank you!

Wayne

Click to expand...

Thank you Wayne For making me laugh been down with the Flu bug for the past few days.
12 TPI AT OVER 200 RPM. WOW YOU ARE REALLY GOOD AT TIMING. Lots of Smiles

Thanks again Chet

iwananew10K said:

Huh?? Back gear has nothing to do with reverse...it simply gears things down approx 5:1 ratio.

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I wannanew10k
I caught myself and deleted before your post, caught myself. Gear reduction. Thanks

mllud22 said:

I wannanew10k
I caught myself and deleted before your post, caught myself. Gear reduction. Thanks

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FWIW-nothing-really: "Back" had to do with where they were physically PLACED. "Backing gear" on a steamship is what it sounds like, functionally. On a lathe, it was location rather than function.

FWIW-even-less-department: The reduction gearing on a 10EE might better be called "Front gears". Silly, maybe, as the greater difference is that they are placed at the power input to the final drive, rather than at its output.

Very different torque vs RPM & HP loadings, and rather more slender ration of metal accordingly, even when more ergs are being conveyed than on a SB 10 with but a quarter the rated HP. Mind - the internal type gears chosen actually have greater engagement of metal than first appears, too. Shorter length. Greater diameter. And "inside out" so the curves trend toward a match, rather than so rapidly away from one.

2 1/2 CW

Since no one else has mentioned it as of yet, you can put the lathe in "reverse" and thread away from the chuck. Check your copy of "How to Run a Lathe" for further details.

-Ron

Dobermann said:

Unless the thread is an strange one and I don't have or can't get a tap for it, I generally don't use a single point tool to cut threads under 3/4" in diameter in the lathe. A tap is much easier to use for that. In the case of an Acme thread, I'd usually do a couple of passes with a single point tool and finish with a tap because the torque required to turn an Acme tap can be pretty high.

In answer to your question about the chips, if you run at slow speed using the back gears, the chips will generally just tumble out of the bore of the workpiece. If not, you can stop the lathe and brush them out with a small, cheap bristle brush. Running at high RPM will keep the chips in place and I can see how that might be a frustration. As suggested above, use the back gears for threading.

Click to expand...

Thank you for the advice. Trust me, I'm lazy.... if I could have found a tap that would work I would have bought one! But, for some reason they used a non standard thread size on the drill stop. Now, I'm not a wood worker, but I cut wood with some other geezers Wednesday mornings, and one of the guys said "why don't you just use some althread and a standard nut...." That would have WORKED perfectly, but then anyone could do that, and I wouldn't have started to learn to cut internal threads, and I would not have learned what a back gear is!!!

Antique Frick Sawmill in operation. Powered by 65 cubic inch Minneapolis Molene engine - YouTube

Thanks again everyone for your advice, the lack of new guy abuse is appreciated.

Wayne

MetalCarnage said:

Since no one else has mentioned it as of yet, you can put the lathe in "reverse" and thread away from the chuck. Check your copy of "How to Run a Lathe" for further details.

-Ron

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so I thought about trying that, I was worried the chuck would spin off and drop on my toe.....

wayneh said:

so I thought about trying that, I was worried the chuck would spin off and drop on my toe.....

Click to expand...

If you're using the threaded chuck, then reverse threading is not recommended (the chuck will spin off). If you're using collets, then there is no threat of any chuck spinning off.

SLK001 said:

If you're using the threaded chuck, then reverse threading is not recommended (the chuck will spin off). If you're using collets, then there is no threat of any chuck spinning off.

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Hmm, good point. Thank you. I was lucky enough that in addition to 20 years of sawdust from a woodworking shop, this machine came with what looks like a full set of South Bend collets.

SLK001 said:

If you're using the threaded chuck, then reverse threading is not recommended (the chuck will spin off). If you're using collets, then there is no threat of any chuck spinning off.

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FWIW - While I'm aware there is a possibility of the chuck unscrewing, I have done plenty of "reverse" threading with a threaded-on chuck without that happening.

-Ron

MetalCarnage said:

FWIW - While I'm aware there is a possibility of the chuck unscrewing, I have done plenty of "reverse" threading with a threaded-on chuck without that happening.

-Ron

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I've done a lot of turning, parting and threading with the chuck in reverse and never had a problem. It still takes a 3-foot bar and a rubber mallet to remove the chuck, even after cutting in reverse.

Maybe a good hard crash in reverse might loosen something up, but I've never encountered it.

wayneh said:

For internal threading on a relatively small diameter part, how do you keep the cuttings out of the threads you just cut? I'm using collets, and all the spiral cuttings are left in the part I am making. I ended up drilling it all the way thru, but then the shavings just end up at the end of the part inside the collet. And it seems like they want to grab the boring bar and damage my cuts.

Next question... 12 TPI has the feed going fast in my opinion. I'm going as slow as I can, but it is still fast and timing has to be right or the slide will crash into the headstock. But they didn't have VFD's 50 years ago?

Click to expand...

Sounds like you need to read How to Run a Lathe (HTRAL for short)

http://www.practicalmachinist.com/vb/south-bend-lathes/how-run-lathe-55th-edition-344476/

Buy one on ebay for the edition close to the year of your lathe...

John

hee,hee...around .3" per second....I think he's got the a pretty solid grip on the threading thing.

comstockfriend said:

Sounds like you need to read How to Run a Lathe (HTRAL for short)

http://www.practicalmachinist.com/vb/south-bend-lathes/how-run-lathe-55th-edition-344476/

Buy one on ebay for the edition close to the year of your lathe...

John

Click to expand...

so my lathe came with that original book, and now I can't find it when I want it. My wife and I have been searching high and low. So off to flea bay I guess for a HTRL book on a 52 South Bend! I've learned a lot in the past few weeks, both from this forum and by playing around.

Thanks to all who jumped in!


Wayne

The HTRAL book never really changed, lots of editions on the web..no need to buy one....that 55th edition is fine.