Thread: Making Indexible Tool Holders

hi dean the way i see it that whole quote is really all about the last sentence.
aaron

The author is correct, you do not need exotic steels for holders..

I have made a few indexable boring bars out of bright mild steel...

Once you make a few for the practice, you work out it is usually easier to buy some off ebay or the likes of CTC...

The author is right about the elasticity module. I found that commercial toolholders for small lathes are not hardened either. They are however made from good steel.

I found the main problem with small tollholders is usually the thread for the Torx screw (and the Torx screw itself). Let me explain. If you use a low quality soft Torx screw, the screw will stretch (say for a CCMT06 insert, the screw is only a tiny M2.5). As the screw stretches, the thread in the soft toolholder gets damaged. Once this is damaged, you can toss the toolholder. Do yourself a favor and use only brand name quality high tensile torx screws. Be prepared to pay $1.50 for each of these tiny screws (unless you buy many). If you use good quality Torx screws, the thread in the toolholder may still suffer over time, if you do not carefully clean both the screw and the toolholder threads at each insert change (blue-tack is a good trick to clean the insert seat). I think this is the main reason brand name toolholders are made with a good steel.

Another thing altogether are boring bar toolholders. These are sometimes made out of massive carbide, the better ones are. The main reason is not hardness, but the lower elasticity module of carbide. And the higher mass which helps dampen vibrations. Chris

Yes, all good advice.

Provided you don't use negative rake inserts all will be OK.

Rob

i have a heap of TCMT inserts I'd like to use up, I'll make a holder if I need to, but I'd rather buy one. Trouble is all I can find on line from Australian suppliers is crappy holders (generally for too much money) and very expensive brand name holders.

CTC who usually supply decent products at reasonable prices don't list a TCMT turning holder.

Any thoughts?

Thanks for the advice. I had not thought of the threads and of course you are right Chris. The threads are going to be the biggest issue. I have replaced the screw and clamp on a straight cutting tool and the screw on a straight boring bar, both Seco. Total cost was around $40 from local Blackwoods but was worth it. They are great tools.

I would like to use the same inserts as much as posible, which is not all that easy. I use CNMG for straight cutting, TCMT for larger boring bar and TPUN for small boring bar.

I will have a look and see what is available but like I have said before at the moment I have no money left to spend on tools. No hurry tho. I am not going to buy to much until I have the new lathe running.

Not being willing to waste money on garbage I am inclined to get good name brand holders.

Dean

Ive made a few of these now. The trick is to make it as big as possible for rigidity, small ones bend on big cuts. Particularly make them as all as you can, use the full height of your toolpost.
You also need to think about getting the chips out.

My favorite is the radius boring bar. This had to be super strong because of the amount of tool engaged for cutting the radius. It was very carefully designed to be as big as possible and still cut to centre at 39mm dia, 70mm deep. Even then, it is *just* strong enough to take the full 12mm cut.
The steel is fairly hard but unsure of the grade. It started as 42mm bar.
Hardware is just standard gr12.9 m5. Yes, i need to make a better clamp for it.



Next one will be an 8" facing cutter for the mill to surface cylinder heads. It will take 12 of my cermet TPMR tips but i will probably buy the NT40 arbor and just make the cutting head.

Originally Posted by andrew_mx83

Ive made a few of these now. The trick is to make it as big as possible for rigidity, small ones bend on big cuts. Particularly make them as all as you can, use the full height of your toolpost.
You also need to think about getting the chips out.

My favorite is the radius boring bar. This had to be super strong because of the amount of tool engaged for cutting the radius. It was very carefully designed to be as big as possible and still cut to centre at 39mm dia, 70mm deep. Even then, it is *just* strong enough to take the full 12mm cut.
The steel is fairly hard but unsure of the grade. It started as 42mm bar.
Hardware is just standard gr12.9 m5. Yes, i need to make a better clamp for it.



Next one will be an 8" facing cutter for the mill to surface cylinder heads. It will take 12 of my cermet TPMR tips but i will probably buy the NT40 arbor and just make the cutting head.

For fly cutting heads I use an old holden6 flywheel minus ring gear and a single point 5/16 sq tool inserted at the radius and set screwed.It is bolted to an adaptor to the mill spindle taper[ cheap as and works forget about 12 tips you want a nice radius cut for the gasket to bite. Been using mine like this for 15 yrs time taken to make 2 hrs money made with it lost count. 0.02cents worth John.

Originally Posted by Oldneweng

Thanks for the advice. I had not thought of the threads and of course you are right Chris. The threads are going to be the biggest issue. I have replaced the screw and clamp on a straight cutting tool and the screw on a straight boring bar, both Seco. Total cost was around $40 from local Blackwoods but was worth it. They are great tools.

I would like to use the same inserts as much as posible, which is not all that easy. I use CNMG for straight cutting, TCMT for larger boring bar and TPUN for small boring bar.

I will have a look and see what is available but like I have said before at the moment I have no money left to spend on tools. No hurry tho. I am not going to buy to much until I have the new lathe running.

Not being willing to waste money on garbage I am inclined to get good name brand holders.

Dean

Hi Dean,

I have a couple of expensive Kennametal tool holders to suit CCGT inserts, too expensive for what they are and I was very pleasantly surprised by the quality of a left hand CCGT holder I purchased from CTC. Others share the same opinion, here's Brendan's - https://www.woodworkforums.com/f65/ct...2/#post1369101

Might be worth a look.

Bob.

I had an idea today and Bob has already kicked the ball off with it. I was going to suggest forumites post of any tool holders they find to be good value and quality and where purchased from. Insert type as well.

I was quoted $150 for an indexible parting tool holder a couple of years ago which I thought was a bit excessive. It may have been Kennametal. This was at a local steel supplier who only had a few bits.

The CTC tool looks good. The SCLCR/L2020K12 is the one I would look at but I cannot find the inserts for them. $30 each for the holders. I presume the SCLCR/L2020K09 holder is the same but with a smaller tip. The prescibed circle is 9.525mm (3/8"). $41 for 10 inserts. I need a left hand one of these. Now to look for threading and parting holders. I am still trying to get my head around the designation for these. The insert chart I am using has both ANSI and ISO codes. I need to look only at ISO.

Dean

Originally Posted by j.ashburn

For fly cutting heads I use an old holden6 flywheel minus ring gear and a single point 5/16 sq tool inserted at the radius and set screwed.It is bolted to an adaptor to the mill spindle taper[ cheap as and works forget about 12 tips you want a nice radius cut for the gasket to bite. Been using mine like this for 15 yrs time taken to make 2 hrs money made with it lost count. 0.02cents worth John.

I looked at using one of my old Supra flywheels, but they aren't thick enough to clear the arbor and keep the cutting tip well supported.
The engines i play with like to blow head gaskets, so surface finish is crucial. The Multi Layer Steel gaskets in particular require a specified Ra finish or they just dont seal -been there, done that.

I need to take 0.080" off the new LPG head for my car, so i will get lots of practice cuts! I will definitely try 1 tip vs 12 and see what it does.

Originally Posted by j.ashburn

For fly cutting heads I use an old holden6 flywheel minus ring gear and a single point 5/16 sq tool inserted at the radius and set screwed.It is bolted to an adaptor to the mill spindle taper[ cheap as and works forget about 12 tips you want a nice radius cut for the gasket to bite. Been using mine like this for 15 yrs time taken to make 2 hrs money made with it lost count. 0.02cents worth John.

hi can you please post a photo of your fly cutter
aaron

This is the German site i mentioned in the Bonelle thread, has some dimensions etc for holders.
MINI-BONELLE-II, von der Schleifvorrichtung zur Universalschleifmaschine

Cheers,
Ew