Will study these as well.
Had a look a their site and was impressed with the TANGRIP as well, although it did seem applicable more for CNC usage only ??
Thanks for taking time to accord us some pointers.
All the best
aRM
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Parting on the lathe
- Thread starter ARM
- Start date
Had a look a their site and was impressed with the TANGRIP as well, although it did seem applicable more for CNC usage only ??
Thanks for taking time to accord us some pointers.
All the best
aRM
I had posted this to help another guy here who was parting titanium and thought I would copy it here as it may be relevant.
I spoke with an old manual guy at work and he said the main problem is the 1\8" size on your tool. Go with a 3/32" with a 20 to 30 deg taper on the top with longest edge to the right and a 3 deg relief down the front. The key is being on center, square with the chuck and rigidity. Put the tool in the holder and verify you are at center, or a hair below, against a dead center in the tail stock. If you have tension stops on the carriage use them. Get in cut off position, tighten left to right and compound stops firmly. Insure you are parallel with the chuck, drag a indicator across the side of the blade if you have issues with this. Put a slight drag on the crosslide stop to prevent jumping in your leadscrew play. Applying the center will help greatly. If you can't center drill the part make a pressure pad out of aluminum with a centerdrilled hole on one side to go between the center and the part. When you get down to near a nub, 1/4"?or so remove center and finish the cut off or hacksaw it. Hand feed only. Like I said trying the 3/32" will help you out a lot. Good luck.
I spoke with an old manual guy at work and he said the main problem is the 1\8" size on your tool. Go with a 3/32" with a 20 to 30 deg taper on the top with longest edge to the right and a 3 deg relief down the front. The key is being on center, square with the chuck and rigidity. Put the tool in the holder and verify you are at center, or a hair below, against a dead center in the tail stock. If you have tension stops on the carriage use them. Get in cut off position, tighten left to right and compound stops firmly. Insure you are parallel with the chuck, drag a indicator across the side of the blade if you have issues with this. Put a slight drag on the crosslide stop to prevent jumping in your leadscrew play. Applying the center will help greatly. If you can't center drill the part make a pressure pad out of aluminum with a centerdrilled hole on one side to go between the center and the part. When you get down to near a nub, 1/4"?or so remove center and finish the cut off or hacksaw it. Hand feed only. Like I said trying the 3/32" will help you out a lot. Good luck.
Not really for us with a threaded spindle. Besides I really watch the chips form which tells me when something is going fruit shaped. You just can't see them upside down until too late. A well ground HSS blade will roll out a watch spring. If one of the corners go dull you can see it in the chip and back out before a crash or taper. Using carbide inserts less chance of something going wrong slowly and with a neutral insert the chip is more barrel shaped and smaller which would lend itself more readily to inverted. With CNC it'd be very advantageous to run inverted. Not being disagreeable but different thoughts. If I did a bunch more parting than I do I would probably mount a parting rig inverted on the backside of my cross slide. Once set it would stay and remove the most common parting problem of thinking it is the right height and square when it isn't.
Here with a little piece of 3/4" 304 SS and a P1 1/2" cobalt blade for illustration I could tell it was running straight and cutting well by the shape and progression of the chips.
I didn't I was making a collet stop and it was in 1018 which I thought would be a good test for the new tool. Incidentally after the test it was cleaned up and returned to the pack to be waited on under the Christmas tree
hew: .I don't with carbide. I will often use thick cutting oil on the outside of the piece. I think it helps get the cut started without chatter though it could simply be imagination.
Steve
) Try freshly honed HSS cobalt cutter and slower turning speed.Hi Arm. I just finished watching a lathe instructional video with a great section on parting including a varity of ways of aligning your parting tool. He also introduced a couple of errors and resulting changes in sound, appearance and quality.
It was one of the last 3 of 10 videos (lathes) from M.I.T.
I think it was video #8.
http://techtv.mit.edu/videos/144-machine-shop-8
Hope it helps!
It was one of the last 3 of 10 videos (lathes) from M.I.T.
I think it was video #8.
http://techtv.mit.edu/videos/144-machine-shop-8
Hope it helps!
I have found that when parting on my lathe, when the chatter starts I need to do two things. First I have to slow the machine down and second increase the pressure, chatter can be caused by being to light on the cross feed pressure. I used to think that when the chatter started I needed to back out or lighten up, when in realty I needed to increase pressure. I always lock down everything that will lock down and I use a lot of cutting fluid, I don't have flood coolant. Since I started to use these little things I have no fear of parting almost anything. bob
Tony I use ISCAR inserts as well. Tried other brands and solid carbide tool stock but nothing has worked as well as the ISCAR brand. Most of the work I do is with DOM tubing, Alum. and some plastics. Whats really great is I can part hundreds of pieces without any problems and when I need to change out an insert its done in a matter of seconds. On my lathes I use flood cooling with cutting oil which can be a little messy but extends the life of the tool greatly.
Mr Arm has askedprivately if I can sell some modified ISCAR Tang-Grip blades and I must say no due to health and other causes but I am very honoured to be asked.
The system is very good in as much as I have only lost one insert trying to grove a case hardened crank pin.
Blade is OK but insert not.
The first question is how big is the maximum depth of cut You can make on Your lathe.I can do 65 mm deep (max130 mm diameter)on a a 9 inch SouthBend clone with my system based on the TGFH 4 blades modified to hold TAG 2 and TAG 3 (and TAG 4 off course).
Startin over again I would have designed around TGFH 5 blades modified for using 1.4 mm and 3 mm inserts
For smaller lathes (7 inch) 1.4mm and 3mm inserts on proper TGHH 3 mm blades will do all You can reasonably ask for.
I do not know from personal expirience if 1.4 inserts sit comfortably on TGFH 3 blaes
My blades were modified using wiresparking EDM but Cold grinding will surely do as well.Carefull.Slow.Small steps.
Please ask if interested and in doubt
Farfar aka Niels Abildgaard
The system is very good in as much as I have only lost one insert trying to grove a case hardened crank pin.
Blade is OK but insert not.
The first question is how big is the maximum depth of cut You can make on Your lathe.I can do 65 mm deep (max130 mm diameter)on a a 9 inch SouthBend clone with my system based on the TGFH 4 blades modified to hold TAG 2 and TAG 3 (and TAG 4 off course).
Startin over again I would have designed around TGFH 5 blades modified for using 1.4 mm and 3 mm inserts
For smaller lathes (7 inch) 1.4mm and 3mm inserts on proper TGHH 3 mm blades will do all You can reasonably ask for.
I do not know from personal expirience if 1.4 inserts sit comfortably on TGFH 3 blaes
My blades were modified using wiresparking EDM but Cold grinding will surely do as well.Carefull.Slow.Small steps.
Please ask if interested and in doubt
Farfar aka Niels Abildgaard
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