Parting

[GK1918]

You got it Paul. The question is? do you have to look at your foot applying your brake or gas pedal on your vehical. If so, those are the ones who
crash through conveniance stores always on the news. Imagine what they'd do with a lathe????

 

[george wilson]

I can't wade through all the responses. Trouble is : STATE THE MAKE AND SIZE of the lathe you're trying to part on. It would help a lot.

The rear located cutoff tool does work better for light lathes. I made one for my 16",but it is easy to back your turning tool away from the work,and run into the rear mounted parting tool.

I NEVER have had a carbide cut off tool. I just use a HSS T shaped blade. HSS is sharper than carbide and less strain on a light lathe. You guys are way too obsessed with carbide. For home shop and small lathes,just use HSS and you';ll be happier. I only ever use carbide when I want to face off my cast iron face plate,as cast iron is very hard on HSS.

Next time,mention what lathe you have. I don't know if you have a 7" HF lathe,or a 14". It is important info.

P.S.: I finally see you have a SB in the 2nd post. Mention it right off and it will help the answers. My back is killing me this morning,and I can't read a lot of posts. Heed my advice about using HSS.

 

[docn8as]

1 FWIW parting off #101 ........... ridgidity ...either open side block holder, flat dough nut in the lantern tool post ...NO rocker ,,,, or quick change ...
2 grind th HS parting blade like they used to be when solid tools were used..viz ,front & side clearance AND front to back clearance ...face of tool is wider than behind ...IMPORTANT
3 grind a gentle back rake using the peripheree of the grinding wheel
4 grind a V in the face of the blade w. the wheel edge ...this will collapse the chip making what comes out smaller than the blade width IMPORTANT
5 blade at rt angle to work & on center
6 no more blade extended than needed
7 do NOT use power feed on atlas crftsmn ..too fast ,,,,hand feed only
8 as stated earlier use a gooseneck ( flexible ) tool holder ..instead of a jam up , if fed too fast , it backs off ( much that the olde tymers knew was correct ....)
9 ...w/ the above ,all problems idsappeared
i have been parting 1018 steel one in in diameter w/OUT any fluid & w/OUT any jam ups ..not recommending , just personal experimenting ....works on crftsmn 6x18 , 12x36 , 1895 Reed 14 in 1918 monarch A 14 in ...havent parted off on pre 1900 barnes #41/2 & prentice bros 15 in ..still making tooling for them

simple CHEAP solutions , one just needs to implement them to work ...if you cant find gooseneck tool holders ,they are easily made from 38-1 in x 2 in bar slot the side for the blade & use grub screws to hold ...form the gooseneck & slot the center of it for flex..if nothing else use hack saws & chisels & grinding wheel ( been there)..a machinist SHUD be able to make his tool s..& all the old tyme apprenticeships started w/ making yyour own tools ( they were expensive to buy for an apprentice to use the next 4 years....)
best wishes
doc

- - - Updated - - -

<br>
1 FWIW parting off #101 ........... ridgidity ...either open side block holder, flat dough nut in the lantern tool post ...NO rocker ,,,, or quick change ...<br>
2 grind th HS parting blade like they used to be when solid tools were used..viz ,front &amp; side clearance AND front to back clearance ...face of tool is wider than behind ...IMPORTANT <br>
3 grind a gentle back rake using the peripheree of the grinding wheel <br>
4 grind a V in the face of the blade w. the wheel edge ...this will collapse the chip making what comes out smaller than the blade width IMPORTANT <br>
5 blade at rt angle to work &amp; on center <br>
6 no more blade extended than needed<br>
7 do NOT use power feed on atlas crftsmn ..too fast ,,,,hand feed only <br>
8 as stated earlier use a gooseneck ( flexible ) tool holder ..instead of a jam up , if fed too fast , it backs off ( much that the olde tymers knew was correct ....)<br>
9 ...w/ the above ,all problems idsappeared <br>
i have been parting 1018 steel one in in diameter w/OUT any fluid &amp; w/OUT any jam ups ..not recommending , just personal experimenting ....works on crftsmn 6x18 , 12x36 , 1895 Reed 14 in 1918 monarch A 14 in ...havent parted off on pre 1900 barnes #41/2 &amp; prentice bros 15 in ..still making tooling for them <br>
<br>
simple CHEAP solutions , one just needs to implement them to work ...if you cant find gooseneck tool holders ,they are easily made from 38-1 in x 2 in bar slot the side for the blade &amp; use grub screws to hold ...form the gooseneck &amp; slot the center of it for flex..if nothing else use hack saws &amp; chisels &amp; grinding wheel ( been there)..a machinist SHUD be able to make his tool s..&amp; all the old tyme apprenticeships started w/ making yyour own tools ( they were expensive to buy for an apprentice to use the next 4 years....)<br>
best wishes<br>
doc

 

[ridgeway]

If anyone is interested, I have some HSS tool bits ground into parting tools as well as ground parting blades that i can take pics and post for ideas..

 

[Payson Greene]

docn8as is right on when he says grind a channel in the top of the blade. I bought an insert holder for our Dorian QCTP. The inserts are all grooved on top, so the chip folds up, on the way out. As the chip is cut, it heats up, and expands. Then it binds up, getting hotter. I've gone back to the blade, in the old Fims holder. It works great, with a u shape ground on top.

Payson.

 

[hermetic]

Sharp tool, bang on centre height, no play in slides, lock the carriage off, no overhang, plenty of coolant, and for me sometimes it works and sometimes it doesn't, and I think parting is just like that. All I know is that it still scares the bejasus out of me, and I avoid it whenever I can! Shakespeare had it right when he wrote " Parting is such sweet sorrow"

Phil
UK

 

[ridgeway]

I don't do much parting, but when I do its usually small stuff and I've just used ground HSS tooling.

 

[Vince]

I must be naive, I have been performing parting cuts for as long as I have been operating my lathe.
I am either lucky or just don't know any better. At first, parting was an issue, but over a few years I can part just about anything.
I have learned to let the cross feed do the work, I select a feed rate I think will be sufficient and lower the rpms. I use plenty of cutting fluid and let it hammer. I have even learned how to part and leave the nubbin on the stock piece.
I first started out parting in back gear but soon found out I had better finish and results by going faster.
All I do is make sure parting tool is perpendicular to work, make sure tool is on center, I grind a slight chip break in tool, I either grind a right lead or a left lead in tip depending on which piece I plan to keep, make sure everything is tight, verify my cross feed (my particular lathe is 1/4 of longitudnal feed), double check everything, and let it hammer. Then I listen to the machine, she will tell me whether she likes it or not.
I guess I have been lucky. Again I go back to the analogy that describes me, "even a blind squirel finds an acorn once in awhile"

 

[schor]

I must be naive, I have been performing parting cuts for as long as I have been operating my lathe.
I am either lucky or just don't know any better. At first, parting was an issue, but over a few years I can part just about anything.
I have learned to let the cross feed do the work, I select a feed rate I think will be sufficient and lower the rpms. I use plenty of cutting fluid and let it hammer. I have even learned how to part and leave the nubbin on the stock piece.
I first started out parting in back gear but soon found out I had better finish and results by going faster.
All I do is make sure parting tool is perpendicular to work, make sure tool is on center, I grind a slight chip break in tool, I either grind a right lead or a left lead in tip depending on which piece I plan to keep, make sure everything is tight, verify my cross feed (my particular lathe is 1/4 of longitudnal feed), double check everything, and let it hammer. Then I listen to the machine, she will tell me whether she likes it or not.
I guess I have been lucky. Again I go back to the analogy that describes me, "even a blind squirel finds an acorn once in awhile"

I am a newbie at all this but I have done a fair amount of parting. The 'last' thing I learned about parting which made me successful was to feed fast and continuous cutting fluid. All the other suggestions are true and I tried them, then finally I found out about faster feeding, I was babying it before.

 

[awander]

One fact that seems to be missing from the mentions of parting with the tool in the rear of the work, is that the lathe still turns in FWD direction, and teh parting tool is inverted(the bottom of the tool, the cutting edge, is at lathe centerline).