Tool Post moved :)

[cmacclel]

Well I finally ran a few parts on the new machine and everything was working great, I machined 6 of my fluted tailcaps minus the threading. The next day after work I stated to thread them. The first 2 went as expected and then the next one took 4 passed of air before it finally started to the lay down some threads!! After measuring them all I have 3 that are what I programmed and 3 that are 0.025 smaller on all diameters! It turned out the toolpost moved while I was blind boring. On a manual machine you can feel when there is chips starting to bind or when there in the way, on a cnc you don't feel didly :)

I machined up a holder support today at work to support the rear of the toolpost holder in hopes of keeping it solidly in place :)

After getting everything adjusted I have less than 0.001 runout on the toolpost and am hoping it stays that way. It would be really hard to drill and tap from a crooked post!

 

[modamag]

Mac, you know we don't want teaser pictures :whoopin:

Come on now give us the whole sha-bang!

 

[wquiles]

In about 2-3 years of lathe work, I have never had the tool post move on either one of my two lathes. Was it loose or not really tight to start with? I don't understand why would it move :confused:

Will

 

[gadget_lover]

As I understand his post, it happened when he was boring. Chips got packed between the end of the hole and the end of the boring bar. Since the bar is offset, it can spin the tool post if pushed hard. Since the machine was under CNC control, it did not stop when it encountered abnormal resistance.

Or at least that's my understanding. I did it on my manual lathe when I was just starting. Very frustrating.

Daniel

 

[TranquillityBase]

Great solution Mac :cool::clap:

QC tool post frustration behind you, it might not be a bad idea to snap the leash on the pooch, and take a cool off walk to the P.O. :poke: The CNC lathe is not man's best friend :grin2:

 

[StrikerDown]

I wonder if there is clearance between the tool post and it's T-nut when torqued down. If there is no clearance then It may be bottoming out before enough clampng pressure is applied to the compound slide.

 

[cmacclel]

I wonder if there is clearance between the tool post and it's T-nut when torqued down. If there is no clearance then It may be bottoming out before enough clampng pressure is applied to the compound slide.

I have about a 1/4 inch clearance :)

I have never seen them move it in the past but yet again I never put 1300lbs of pressure in "Z" on a part :) The "Z" Ballscrew on this machine is like just under 1.5" in diameter!

Mac

 

[Anglepoise]

I have about a 1/4 inch clearance :)

I have never seen them move it in the past but yet again I never put 1300lbs of pressure in "Z" on a part :) The "Z" Ballscrew on this machine is like just under 1.5" in diameter!

Mac

In the past mine has occasionally moved when knurling. Even when I had it really tight.(...or so I thought )

I finished up with a retractable pin that I could drop down when needed
that locked the tool post center bit to the top slide.

 

[Torque1st]

Man, I have run thousands of parts on a manual lathe. Many times removing 1" on the diameter at 0.040/rev in 4140 on 20" diameter parts or 1/2" on the diameter boring (3"dia bar at 14" extension) and I have never had the tool post move.

 

[cmacclel]

Man, I have run thousands of parts on a manual lathe. Many times removing 1" on the diameter at 0.040/rev in 4140 on 20" diameter parts or 1/2" on the diameter boring (3"dia bar at 14" extension) and I have never had the tool post move.

Your probably using a DA or EA toolpost :) Mine is one size under what is usually on my machine.

Mac

 

[PhotonFanatic]

Mac,

You could snag this from me--it won't move, I promise!

 

[cmacclel]

WoW thats a monster post!!

Mac

 

[Torque1st]

Your probably using a DA or EA toolpost :) Mine is one size under what is usually on my machine.

Mac

I was using a 24"x60" 10HP Okuma lathe with one of the old 4 sided indexing Turret type toolposts with bolts. Only one person on the lathe line had one of those Aloris type posts and all he ran was small parts. The boring bar holder was shop built.

Photon, that tool post is about what I need for my new lathe. :)

 

[PhotonFanatic]

Torque1st,

I have it up for sale on Practical Machinist--it is a Swiss Boni toolpost--very well made, and way to big for my lathe. :-(

 

[wquiles]

Torque1st,

I have it up for sale on Practical Machinist--it is a Swiss Boni toolpost--very well made, and way to big for my lathe. :-(

Fred: I have seen partial photos of your lathe, but I don' recall seeing a full size pic - what size is your lathe? Do you have a good picture/link to the full lathe?

Will

 

[PhotonFanatic]

Will,

Not a picture of my machine, but it will give you all the details you could ever want.

 

[wquiles]

Will,

Not a picture of my machine, but it will give you all the details you could ever want.

Thanks Fred. I am a pretty much visual guy, so now I can "see" what you use to make your wonderful lights ;)

Will