Insert Tooling

[Omnimill]

I bought a nice lathe tool a while back that takes DCMT 070202/04/08 inserts. I like using it a lot but the inserts, being quite small don't seem to last very long and only have 2 cutting tips.

What I'd like to try are the double sided Triangular or Tri-Lobular inserts which give 6 cutting tips and are mostly the same price (on eBay) as the DCMT inserts I'm using at present.

Anyone got any advice on the subject as I don't want to end up investing in tooling that isn't going to work well in my 8" X 14" Lathe. The smallest toolholder for most of the inserts I've seen is 16mm square so I'l need to trim a few mm off the bottom to get centre height.

Vic.

 

[wizardofwood]

Hi Vic
while I am not familiar with your machine I have used the inserts. I assume you are refering to the 'W' type inserts such as WNMG?
Generally the double sided inserts generate higher cutting forces and on a small machine may give problems with vibrations,
I have found the double sided inserts are usually better for rough turning and would always prefer a DCMT for finishing with.

Byrne

 

[Tin Falcon]

start looking here. http://www.arwarnerco.com/ Mike is a great guy this is high quality made in USA tooling . all sets come with HSS inserts and some come with carbide as well and carbide can be purchased. Mike HSSMike contributes here from time to time as he can. If you can get to a ME show where they are vendors you can save a couple bucks off the list price. T ey often have show pices and no shipping.
Tin

 

[Niels Abildgaard]

I have used a standard tool with CCMT 09 inserts a produced a lot of swarf and many unused 100 degree corners on the inserts.
I have made and tested a much cheaper and better tool that removes metal and makes surfaces I did not think possible on my old Boxford.
Next version will be for CCMT 12 inserts that comes very cheap and often on Ebay.

 

[Omnimill]

Nice idea Niels, I may have a go at making something similar now my Mill has arrived.

Vic.

 

[Niels Abildgaard]

Hello Omnimill

Will it spoil Your fun or be helpfull if I give a step by step procedure based on NOT having a mill?

 

[Omnimill]

Hello Omnimill

Will it spoil Your fun or be helpfull if I give a step by step procedure based on NOT having a mill?

By all means Niels, I'm sure others would like to see as well!

Vic.

 

[Niels Abildgaard]

Hello Omnimill
CCMT inserts come in different sizes and thickness so dimensions will have to be changed to what You have or can easily find.My first were ccmt 09`s with a thicness of 1/8 inch.The industry prefer them a little thicker 3.97 mm and as I found quite some with unused 100 degree corners on a school I decided to make a new ship-like holder for these.I had planned to photograph the steps but they went so well and fast that I forgot.

1 Know Thy Lathe:
To find the center-heigth over tool-slide surface I turned something until a 10 mm Toolbit could just pass under. On my old Boxford this was measured and calculated to 25.14 mm.The CCMT are 3.97 mm thick and therefore bottom -deck distance of my ship-like body must be 21.07 mm.This was done in my four-jaw and result was within 0.01 mm.Bow to Transom is approximately 100 mm and seems to fit my Boxford.

2 Choose Thy Weapons.
Four of the school inserts beyond hope of reuse had a corner ground of. See picture.This is for clearance.

3 Prepare for cutting Yourself off
Glue the four corner-cuts upside down plus two usable in their more or less correct position.I used cyankrolate and got connected to my work.

4 Drill and tap the holes for the FOUR upside down corner cuts inserts.I made a guiding bush with a hole of 3.2mm for tapping M4 thread and it had an outside diameter of 4.4 mm to suit the hole of the inserts.DO NOT DRILL FOR THE ACTIVE INSERTS YET.

5 Heat
Use an oven to 150 degree celsius to destroy glue.
Clean parts for glue residues.

6 Stop and think
I choosed M4 UNBRACO screws of 12.9 quality to keep the corner cut upsidedowner inserts tied down forever and it means forever. And very rigid too.This is the point where my step by step procedure really needs improving.
I tigthened the screws holding the cornercut as hard as possible and off course their relative angle was not correct so a spanner was used testing against a usable insert in the correct cutting position.Very unsatisfactory from an intellectual standpoint.Please help.

7 End is near
Most manufacturers fix their active ,CCMT 9 inserts with TORX PLUS M 3.5 screws but by accident I used M4 and this works OK.It is important that the active inserts is pushed hard against the upsidedowners.
To achive this another guiding bush was made: 3.2 mm central hole for tapping M4 , 4.4 mm body and a brim .8 mm thick that lifts the insert so that it really sits thigth afterwards when it comes down the 7 degree slope of the upside downers.

 

[Omnimill]

Thanks for that Niels, interesting stuff. I'm glad the M4 screws worked, I wonder if they will fit the 11 04 DNMG's I've ordered from eBay!

Vic.

 

[Niels Abildgaard]

Using the shiptooler CCMT holder almost every day expirience suggest that the next will look a little different.

Regards

Niels Abildgaard

 

[BillTodd]

That is a really neat idea Niels :bow:

Bill

 

[dy]

Insert tooling, for positive ground inserts. (222 if I recall their size correctly - the 'commonest' variety work well.)

Materials: 7/16ths drill rod, 7/16ths cold drawn W1, 1/4 inch brass rod for shims, 8-32 (?) socket head screws, heat source, quenchant.

Oh, and a lathe. You make these ON the lathe. I did not use a milling machine. More, I used a 7X10!

1) Using the lathe and an arbor-mounted slitting saw, cut off several suitable lengths of that W1 stuff. Debur the pieces with a fine file.

2) Using the aforementioned lathe and slitting saw, cut your shanks such that they're fitting your inserts. I used the smallest common ones
I could find, those having 1/4 inch included circle, triangular, positive ground for three cutting points. I made a right, a left, and a center. Debur
the pieces with your file(s).

3) using a 1/4 inch carbide end-mill, cut out the sections where the inserts will go. Note that you will need to go VERY slow, both as to speed
and feed. Use a fresh end-mill, or if possible, use a slightly undersize one for roughing and finish with the fresh one. I ended up needing a THIN
brass shim under mine due to clean-up aspects. Again, debur with a file or three. I'd recommend using a fine three-square one for this job.

4) chuck up the drill rod, face the end. Now, using a brass block or stack of shims between one of the three jaws of the chuck, chuck the drill rod off-center. You're going to make the clamp now.

A) bore a place for your tailstock with a center-drill.
B) turn the 'shank' of the thing. This needs to be .250 long, and .250 diameter. ( I think. I've got the lathe in pieces right now and the whole
area's an unholy mess. It will remain that way for some days yet, due to illness.)
C) undercut an area around the shank on the underside of the clamp's 'head'. This gives a small 'bump' for the insert, which you'll cushion with a brass shim.
D) drill a passage for an eight-32 socket-head cap-screw.
E) part off the piece. Chamfer and debur. Set aside.

5) return to your shanks. Drill, tap, and then ream the appropriate place for the clamp to go in. See drawing. Debur, test-fit parts with insert.

6) make the shims such that the clamp holds the insert in place.

7) heat-treat shank and clamp - use oil for both. W-1, least in small sizes, does get fairly hard. Draw shank back to a medium to dark straw, the clamp to a purplish blue.

See drawing (I know, not too good. I've got a sinus infection, and a headache that's bad enough to make me wonder about migraines.)

dennis

 

[dy]

I'm better, but not over that cussed sickness yet. Still, managed to dig out much of what I need to do so as to post pictures. Updated drawing follows.

In looking at the pieces for these, I'm mildly amazed that I did as well as I did. The camera battery is charging right now. I hope to post pictures within the next few days.

dy