A question for the actual machinists here about tool pressure.

[DaveTooley]

The top pic is the conversational program. I enter all the values in the right window and the machine builds everything it needs to do the operation ( left window ). The bottom pic is part of a sequence of operations linked to complete a job. Below the G71 you'll see a chamfer move with the same tool. Then a parting operation where I use a grooving tool to plunge in and cut the tenon to length. The grooving tool knows where it is, knows where the work piece is, how far to go and to what depth to plunge.

 

[ELR LVR]

Ebay for the inserts. I like 5/8 holders.

You no like 3/4" Holders? :/

 

[ELR LVR]

You don't need a breaker bar to tighten your spider pins up.a decent pinch is enough.four pins opposite each other at each end of the barrel is sufficient to hold most thing's you want to turn.your machines rigidity will play a key part.a heavy 3phase machine.will turn and thread a tennon alot easier than a light single phase one.more torque and rigidity is better.tool set up and work piece set up.you don't want your tennon sticking out further than needed.keep it as close to the head stock as possible.dial everything in as perfect as can be.use quality tooling.the cheap micky mouse stuff is no good.turn and thread to your machines capabilities.dont get greedy with your cuts.

As far as a 4 bolt spider goes
it is merely to "Support" the barrel, more so than grip it
I would not personally want to use a 4 bolt spider on both ends
4 Jaw on the turning end to GRIP, and spider on the back merely to support
I dial in the spider then merely snug it ever so slightly, then lock the lock nuts down
The back of the barrel stays supported and nothing comes loose
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Anyone else may do as they wish though

 

[Sniperhandle]

You no like 3/4" Holders? :/

He is talking about the tool that holds the insert.

The 250-201XL tool holder that mates onto a BXA tool post will hold a 3/4 inch tool, There are others that are marked "250-201T" that will hold a 3/4 inch tool also, But they will not hold the 20mm Tools, I have used a fly cutter to turn down those tool bit holders to fit the BXA tool holders, The tool holders are quite hard and you will need a carbide fly-cutter to cut them down to size.

A standard 250-201 BXA tool holder will fit 5/8 or 16mm or smaller tool bit holders, The 250-202 has a small groove cut in it for using a round shank tool.

 

[ELR LVR]

He is talking about the tool that holds the insert.

The 250-201XL tool holder that mates onto a BXA tool post will hold a 3/4 inch tool, There are others that are marked "250-201T" that will hold a 3/4 inch tool also, But they will not hold the 20mm Tools, I have used a fly cutter to turn down those tool bit holders to fit the BXA tool holders, The tool holders are quite hard and you will need a carbide fly-cutter to cut them down to size.

A standard 250-201 BXA tool holder will fit 5/8 or 16mm or smaller tool bit holders, The 250-202 has a small groove cut in it for using a round shank tool.

I tested the difference between my Actual Aloris and Ebay copies...
I do know the Aloris tool holders are so hard, a file skates right across them
The chinese/Ebay 250-??? BXA Holders...a file can cut them rather easily, they seem to have no hardening.
So I would think they would machine and can be modified easily enough.
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My bad, regarding the "INSERT" tool holder lol
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Knowing the differences, when I need tight tolerances and no flex...I use my Aloris
When it's small cuts and not much tool pressure, I may use the Ebay copies.
The Ebay copies do the job for most operations, and are thick enough I don't see what it would take to flex them even if they were made out of mild steel .... lol

 

[X Count]

Have a look at multifix tool holders / post. More angle options than the aloris and extremely solid lockup. Because you don't need to unlock the tool post to set an angle I'll often use the same tool at 2 different angles with 2 different zeros in the DRO. I'm running 25mm holders and have enough height adjustment to run 1/4 to 1" tools without packers.

 

[ridgeway]

I have both, Aloris and ebay holders and both work perfectly fine. I find that replacing the set screws on ebay holders is a nice upgrade. Modifying the holder to let say make a larger opening...can be cut no problem on a mill using carbide. Or simply modify the holder to accept the holder. I've taken 1" tools and modified them to fit my small AXA holders. Carbide is wonderful.

 

[Jonnyofalltrades]

My insert of choice for 416 stainless is actually made for aluminum. Positive rake, razor sharp, and cuts 416 like butter. 416 really is not much different than 7075 aluminum..050 depth of cut is a piece of cake. I can post a pic of the inserts if anyone is interested. Basically razor sharp carbide. Let me know.
Paul

This is really good advice. Most of the tens of thousands of inserts out there for steel these days are geared towards maximum productivity. 1000- 1500 SFM with an aggressive depth of cut and feedrate.
Not at all suited to the tiny amounts of steel being removed here.

 

[LVLAaron]

KC5010 is the grade of coating not the profile. Both profile and coating influences how the insert works.

https://www1.mscdirect.com/images/solutions/kennametal/grade_system_for_cutting_materials.pdf

I use this Kennemetal insert with the KC5010 coating. They will take very small cuts at pretty slow speeds on a manual machine but they are fragile. They were recommended to me by gunsmith Bill Myers years ago who had a friend that worked for Kennemetal at the time. I met him but I don’t recall his name. Bill needed an insert to work with the Ti he was machining at the time for his actions. They work very well on other materials as well.
View attachment 1656699View attachment 1656700

I found some of these in a KCU10 grade. They're awesome! Great surface finish and cut like the polished inserts do.

 

[SKWERLZ]

I found some of these in a KCU10 grade. They're awesome! Great surface finish and cut like the polished inserts do.

Did a test cut on a barrel stub with the kc5010 inserts (dcmt32.51)
Those are vastly superior to the inserts I was using.

 

[LVLAaron]

Boom. kc5010 is the bees knees. And inserts are plentiful on ebay!

 

[ELR LVR]

Boom. kc5010 is the bees knees. And inserts are plentiful on ebay!

Also to point out to everyone
50 series is superior (high hardness finishing grade)
be sure not to make the mistake of getting 55 series just because it Kennemetal (IE: 5510, 5525)
which I've read is junk and you'll go through them like 109 times faster.