indexable insert size questions

[Jawn]

I want to try indexable tooling and have a couple questions about insert and toolholder sizing

1. Is bigger always better? There are turning insert holders I'm looking at with 3/8 and 1/2" shanks. I am fairly certain a 1/2" will fit, will confirm.

2. I'm looking at CC__ inserts (CCMT, CCGX, etc) Some holders I'm looking at use 21.5_ inserts, some use 32.5_ inserts. Any advantage or disadvantage to either insert size, within the realm of a hobbyist? I am looking at a couple boring bar sets, one's 5/16 to 5/8 using the smaller insert, the other is 1/2 to 3/4 using the larger insert. Which do you think would be more useful?



This will be on a Grizzly G0602 (and I plan to stiffen the compound in some way, perhaps a 4 bolt mount). I realize a benchtop lathe has some real limitations in this area and many will say just stick with HSS, but I am willing to give this a shot. It seems to work for some people with such machines. I anticipate using it as a way to speed up material removal for roughing, before switching to HSS for finish work.

[warmstrong1955]

It all depends on the work you are doing, the material you are working with, and how fast you want to do it.

Bigger is more rigid, but not necessarily better.....

Insert tooling, I use 1/2" tool holders that use TCMT-32.51 more often than any. Advantage....everyone has 'em and they are cheap.
I also have some 3/8" holders and misc boring bars that use CCMT-21.51, that I use for smaller parts.
And, I have others that use different inserts too.
And....I have a heaping shoebox full of HSS tools, most all hand ground, along with various holders to fit the need.

Can't have too much stuff!


Bill

[Jawn]

Well, bringing TCMT into this discussion... I see Shars has a no-name TCMT holder that directly fits an AXA/100 size toolpost.

http://www.shars.com/turning-and-facing-holder-16-axa

It does give me three corners per insert.

[warmstrong1955]

I prefer the square shanked insert holders for turning & facing, that fit into the regular grooved AXA tool holder. Easy to adjust the stand-off if need be, or tweak the angle a bit without takin' the whole tool post out of square.
And...they are inexpensive.

If you're a Shars fan, I'm sure they have sets. Take some lookin'...their search engine leaves much to be desired.

Bill

[warmstrong1955]

Or Grizz.... where I got one of the sets I have.

http://grizzly.com/catalog/2015/main/698?p=698

Bill

[Richard_W]

If you can take a 1/2" shank tool holder, then that would be the one to use. On your lathe the smaller insert would work fine if you could get it in a 1/2" shank.

Richard W.

[SteveM]

Nice thing with the C inserts is that you can get a holder that presents the bit to the work so that you can turn and face with the same tool - no need to change.



Disadvantage is that you only get two cutting edges, vs 3 for the T inserts.

They make toolholders to use the 100 degree side, and I want to get one so that I can use the extra two sides as the inserts are free.

If you want information on the nomenclature of inserts and toolholders, see here:
http://carbidedepot.com/resources.htm

T inserts are very popular and you can get lots of them cheap on ebay. You can get C inserts, but not as popular or cheap. When you start getting into D, V and W inserts, it starts getting pricier. W is nice as it has an 80 degree edge, which is stronger than the 60 degree edge on a T, but it has 3 sides and not 2.

Steve

[Jawn]

I think for turning/facing holders it'll come down to one of the following three:

Glanze holders, takes CC__ 21.5_ inserts. Lots of different style holders, do I need all those? Does include a small boring bar though, that could be handy.
https://www.grizzly.com/products/Glanze ... -1-2/H5681

AR Warner holders, takes CC__ 32.5_ inserts.
http://www.arwarnerco.com/p-15-kit-11-1 ... -hand.aspx

Third option is the Shars TCMT holder I linked to earlier.

[Richard_W]

I think for turning/facing holders it'll come down to one of the following three:

Glanze holders, takes CC__ 21.5_ inserts. Lots of different style holders, do I need all those? Does include a small boring bar though, that could be handy.
https://www.grizzly.com/products/Glanze ... -1-2/H5681

I would get this one because of the smaller insert, I don't think your lathe has enough power to warrant the use of the larger insert. I get good life with this insert on small bores on a 30 HP lathe and even with a 16" chuck I do have to use a 3/8 and 1/4" boring bars at times. So you should do just as well also on your lathe. Use this smaller insert at home in my heavy metal boring bars on my 16" lathe.

You won't always use all the holders, but when you need one you will have it already.

Richard W.

[Jawn]

Sounds like a winner.

One last thing... I measured how large a bit will fit, with the tool holder all the way down it appears to be exactly 1/2" from lathe center to the inside bottom of the tool holder. Do the inserts protrude above the top of the holder, or are they designed to have the cutting edge sit at or below that height?

[Richard_W]

Sounds like a winner.

One last thing... I measured how large a bit will fit, with the tool holder all the way down it appears to be exactly 1/2" from lathe center to the inside bottom of the tool holder. Do the inserts protrude above the top of the holder, or are they designed to have the cutting edge sit at or below that height?

All the ones I have seen the top of the insert is the height as the top of the shank. I would buy the 1/2" shank holders from what you have written. I don't know about the other dimensions if you were to upgrade to an Aloris wedge type tool post though.

Richard W.

[Jawn]

Sounds like a winner.

One last thing... I measured how large a bit will fit, with the tool holder all the way down it appears to be exactly 1/2" from lathe center to the inside bottom of the tool holder. Do the inserts protrude above the top of the holder, or are they designed to have the cutting edge sit at or below that height?

All the ones I have seen the top of the insert is the height as the top of the shank. I would buy the 1/2" shank holders from what you have written. I don't know about the other dimensions if you were to upgrade to an Aloris wedge type tool post though.

Richard W.

Ah, I do have a wedge type quick change (phase II). Those measurements are based on using the standard #1 holder that came with it. Thanks for the advice!