Lathe Refurbish Help...

[bullnerd]

Thanks for the floor pic Joe,I also like the VCT.I also like the un-polished look when it gets beat up. It looks like an old shop floor.

Have you ever turned a nice clean burr free thread, On any lathe before? I dont want to sound out of line but there are some tricks to getting a smooth finish when single point turning a thread.

 

[jxxxoxxxe]

Thanks for the floor pic Joe,I also like the VCT.I also like the un-polished look when it gets beat up. It looks like an old shop floor.

Have you ever turned a nice clean burr free thread, On any lathe before? I dont want to sound out of line but there are some tricks to getting a smooth finish when single point turning a thread.

These are the first things I've threaded... I need to try it on a real piece of material and not rebar or black pipe...

Any tips or tricks? Faster? Slower? Depth of cut?

 

[2oolhound]

I'm amazed!

 

[A_Pmech]

Come on, give me a little credit...LoL...If I told ya I grounded it directly to one of those new bearings I put in there, would it make you cringe...?

Believe me, I've seen it done before.

"Hey! We don't have a welding positioner so lets just mount this in the lathe and ground the headstock. Set the machine to bottom gear, slip the clutch and... Hell yeah!"

Later that day:

"Why does this machine HOWL in top gear? It didn't yesterday...."

***SHUDDER****




P.S. Put the back plate in each possible position on the spindle nose and check the runout. If the runout follows the backplate take a skim cut on it.

 

[bullnerd]

"These are the first things I've threaded"-Your doing pretty good then.It will only get better with more practice.

Could you take a pic of the tool and compound when its set up to cut?

I dont want to derail...but my friend once clamped the ground of his dads old arc welder to the G-door track! All he knew was it had to be clamped to metal.

 

[jxxxoxxxe]

Here are a couple pics...

Here's how I've got it setup....My compound is labeled 61* at this spot...I used a thread center gauge to make sure the qctp was square to the work

This was on some real material, was in my first post...looks decent to good to me...

This is some black pipe...

So is this...

I really think the finish issue is mostly the material and not me.....at least I hope...


If you can look closely in this pic, I dont seem to be getting a good shape to the threads. They dont appear to be 60*. The left side looks ok, but the right almost looks more vertical...

Whats causing that? I am resetting the cross slide to 0 each time, and feeding in .003-.005 with the compound...

I've noticed that there are different sized threading inserts. How do you know when to pick which size? is it determined by the tpi? Even then, isnt 60*, 60* no matter the size of the insert?

 

[darkk]

Looks like the cutting tip isn't angled / aligned correctly.

 

[antinym]

Even on the "good' threads, the threads aren't even. I think your tooling is off.

 

[bullnerd]

I set the compound at 29-1/2 Deg.

 

[jxxxoxxxe]

Yea, I was considering trying to move it a half degree and see if I get any difference...

I've used a gauge to alight the qctp and tool. I'm sure I'll have something to thread in the coming weeks. I guess I'll just try again...the finish is one problem, but the flanks of the thread not being 60* is another....

 

[bullnerd]

29-1/2deg.(30 really) , NOT 60deg. The thread is 60 deg. included.

 

[justanengineer]

29-1/2deg.(30 really) , NOT 60deg. The thread is 60 deg. included.

Some of the Asian lathes have the labeling on the compound reversed compared to a US lathe. I agree that the OP should check to be sure he is ~30 degrees from a straight parting plunge cut, but I suspect there may be a bit of "mislabeling" occurring.

OP, it looks like youre using carbide insert tooling, in which case I would hope your cutter is the correct tool and "ground" properly. That being said, I would bheck the angle of the cutter with relation to the workpiece/chuck etc. I just manually place the side of the toolholder against the large flat face of the chuck to get the two parallel.

 

[larry_g]

http://www.youtube.com/user/mrpete222/videos?query=clausing&sort=dd&flow=list&view=0
In the above link are two videos on threading on the Clausing . There are others by the same guy. Peruse them and see if you cannot figure out what is wrong with your method. You are getting what looks to be a butress thread there which telles me your tool is not ground correctly or the angle of the feed is wrong. Are you using a fishtail type guage to set up the bit angles?

lg
no neat sig line

 

[bullnerd]

"Some of the Asian lathes have the labeling on the compound reversed compared to a US lathe. I agree that the OP should check to be sure he is ~30 degrees from a straight parting plunge cut, but I suspect there may be a bit of "mislabeling" occurring."

I thought of this after my post,good call.