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Parting Tool

Texasbowhunter

Aluminum
Joined
Oct 11, 2019
I'm in need of some guideness
I have purchased a nice used lathe 2 years ago or so and have been learning to use it from time to time...
Well The portion of the operation I'm failing at is the parting portion of the operation...
I presently have a HSS parting tool...Its not the "T" type which I had read is better then the standard HSS tool...
I have to sharpen it constantly
I have followed the information I have seen on Video to a letter on set up and still don't get a quality parting...It seems to try and cut but will not bite and when it does part the cut is very telling of marks on the cut surface...its not pretty...its very unprofessional finish...
I have the speed slowed down and plenty of lube and on occasion when it does cut, it wont cut the next time...Very unsettling for me...
Granted the HSS may be an inferior item and am sure it from China and of poor quality...
I have entertained the "T" shaped but am concerned that it may be of sub standard performance since...
I have tossed around the idea of investing in the Carbide in which I feel would be the better way to go...
However I'm at the same dilemma I have been in when looking around at what's available out there with potentially inferior tools...
So I am a novice user learning to use the lathe and seemingly would like to consider the carbide cutters and am at a loss as to what is a higher quality product to choose...Popularity would be a plus which would seem to imply cutters would be more available...
There seems to various styles to choose from and is not for the faint at heart...
So what style would you suggest for the carbide style parting tools available with brands of carbide cutter brand...
Pics if possible would be nice...Just so I order the correct ones...
On a outside note are the Mitsubishi cutters inserts quality any good...I understand the Kennaland are like the gold standard I presume since the cost is very high and for a novice the cost is a bit prohibitive and have to consider something that will perform as well but at a lesser cost...
Thanks
Paul
 
A quality HS T shaped blade can last a long time in optimal conditions like a screw machine flooded with oil and cutting 12L14, I am a little miffed if mine do not last for 30,000 parts. Same part in an abrasive material like copper and it might only last 100 parts. The last time I ran copper I got carbide "T" blades from Somma. Incidentally I try to buy only T15 HS blades from companies like Somma or Empire.

You have not mentioned material which could be the problem with your results you are not happy with. I just did a short run with ToolFlo and Hertal inserts on Allen screws. Too short a run to tell if they last as long as the old Manchester S2 Seperator inserts, but it looked promising.

We will have to know more to help you. Material, rigidity of the holder, PRM, coolant or cutting oil, and feed rate are all part of the equation.
 
Hard to know for sure without more detail, as stated above, but your description is consistent with the tool centre height being too high. Experiment with slightly different centre heights and take note of what changes. Work with what you can change before buying new tools. Unless the tool and/or lathe are absolute junk you will be able to make them work eventually. If your standard blade is not working a t blade or carbide probably wont either.
 
Thanks Guys
One of the materials was Hot Rolled Steel...Some material I had around the shop to learn on...
The coolant was brushed on Tap Threaded Lubricant and the rate of speed was done by hand...I have a VFD to control the speed and turned it down to about 20% which seemed to work better and actually get a bite on the material to cut...
I have the parting tool loaded up in a holder that is used in a BXA Bolstar wedge lock system...I'm not set up for coolant at this time...not sure if the cost will outweigh the need...
Thanks
Paul
 
I have taken this into account and played with the various heights of the tool and got various results...
I had even found the center of a facing cut and adjusted the cutter to the point of taking the nub (point) off when setting up the blade to ensure it was in the center...
Again when doing this it seems to cut but the finish is ugly and the next time I use it its like it doesn't want to cut
For me a inexperienced user it seems its dull knowing I just used it...
Are there any videos out there that shows the proper steps to put a edge on and what to look for in getting the best edge for long time usage...
 
A36 is not the best material to learn cut off with. It is gummy. I would have said 1018 CD was better but I have run into tool wrecking inclusions in it and will not run it in production any more. Get you some 12L14 or c1137 to practice on. On center when you finish does not mean your set up is rigid and you are on center 1/4 way through. I really like to pour the oil on when cutting gummy materials.

I have some C1137 hex bar ends, send me a PM and I will give you a couple.
 
Best option is an insert parting tool. It folds the chip in on itself away from the walls of the cut. Blade parting tools that have flat tops are the worst thing you can use. Buy a parting blade that is ground with a shallow full length recess along its top side. Buy it in cobalt for extra life. Or..grind a shallow channel along the top of your blade. The groove/recess folds the chip for a free bindless cut and the chip rolls up during the cut. You should be able to part at about 1/4-1/2 the speed you used while turning that part. Use lots of lube.
 
so I assume you know about setting height using a scale (ruler), but if not:
move the cutter to the material, stick a scale between the cutting tool and material so that it is trapped vertically in between. if the scale is straight up and down you are on center. If not adjust it to on center.

Parting should be done as close the the chuck as possible. If you get to far out it will chatter, and worse, it may wind up that the piece will ride up on top of the tool. Don't ask me how I know :nono:

keep the feed cutting , not hard, but not too light. if you pull out and leave a burr, it's often hard to re-enter. The burr can grab.

edit: sharpenning: for your tapered parting tool, just bring the face of the parting tool to the grinder face and move it back and forth. it will automatically build in a clearance when it follows the wheel. just a few light passes, then take a very fine stone and remove the wire edge on top and the sides of the tool. I polish them with a translucent hard stone .
 
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edit: sharpenning: for your tapered parting tool, just bring the face of the parting tool to the grinder face and move it back and forth. it will automatically build in a clearance when it follows the wheel. just a few light passes, then take a very fine stone and remove the wire edge on top and the sides of the tool. I polish them with a translucent hard stone .

I have not done this portion and will give a try...This should fix the rings where the parting is going on...
FWIW...I use a belt sander to address the HSS Parting tool...
Yes I have tried the method you spoke of centering the tool on the diameter with a ruler...
I'll try this again and see where the ruler falls in relation to center I have presently set up where the parting tool is removing nub off the end...
Thanks
Paul
 
I have not done this portion and will give a try...This should fix the rings where the parting is going on...
FWIW...I use a belt sander to address the HSS Parting tool...
Yes I have tried the method you spoke of centering the tool on the diameter with a ruler...
I'll try this again and see where the ruler falls in relation to center I have presently set up where the parting tool is removing nub off the end...
Thanks
Paul

You doo what ?
 
Yea I have a 2 x 72 belt grinder table mounted I have used to profile and attempt to sharpen the tool...
Is there a problem with this method?
paul
 
Are you using power feed or hand feed on the compound? I have found over the years that using power feed is one key to getting a good cut. It is difficult (not impossible for sure) to use hand feed and get a good cut. Push too hard and the tool grabs or worse yet, starts to ride up. If you get a good speed and feed going with power feed the tool will make a nice curly chip that stays out of the way. Of course some material will not make a good curly chip no matter what you do. I think your poor finish could be from chips getting down beside the cut off tool and dragging.
 
Are you using power feed or hand feed on the compound? I have found over the years that using power feed is one key to getting a good cut. It is difficult (not impossible for sure) to use hand feed and get a good cut. Push too hard and the tool grabs or worse yet, starts to ride up. If you get a good speed and feed going with power feed the tool will make a nice curly chip that stays out of the way. Of course some material will not make a good curly chip no matter what you do. I think your poor finish could be from chips getting down beside the cut off tool and dragging.



Are you referencing the fact that I have not addressed the edges of the parting tool after I had profiled it?
No Im not using the power feed at this time...free hand
 
I have not done this portion and will give a try...This should fix the rings where the parting is going on...
FWIW...I use a belt sander to address the HSS Parting tool...
Yes I have tried the method you spoke of centering the tool on the diameter with a ruler...
I'll try this again and see where the ruler falls in relation to center I have presently set up where the parting tool is removing nub off the end...
Thanks
Paul

removing the nub is good enough, it indicates you are on center.

as far as sharpening with a belt sander, well, I don't know.

A) are you including clearance under the cutting edge?
B) is the cutting edge straight across? It doesn't have to be square to the side, as you can bias it for one side of the cut by a single degree or the other side.

C) is the belt rounding the cutter's top cutting edge????? if it is you won't get the edge you need. If you don't have a grinder, well..... A grinder has it's purposes, and a belt sander has it purposes.
 
Try this: turn tool upside down and run it in reverse. Sometimes will work if machine is worn. Make sure you've got enough clearance.

good idea but will not work most of the time because of height adjustment. besides you need a right hand tool.

op, get this, it works:

MZG KGMR1010F 1.5 85 KGMR1212F 2 85 CNC Lathe Groove Machining Cutting Toolholder Cutter Parting And Face Grooving Tool Holders|Turning Tool| - AliExpress

try with aluminum, then free machining steel. a belt grinder is not the best choice, unless you know what you are doing. the belt tends to round off the edge.
 








 
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