Which insert do I need?

T

TonyBen

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I bought the Aloris SGIH 26-4C-B7 cutoff blade but I need an insert. The blade is 0.125" wide. I don't know why, but Aloris sells inserts that are thinner than the blade holder, maybe for grooving, but I need an insert that's wider than the blade, so it looks like the narrowest insert available is the 0.160" insert. They sell them with a 0˚ lead angle and one with an 8˚ lead angle. Which one do I need for cutting gun barrels, both chrome-moly and 416 stainless?

I'm using a BXA-7 holder:

Universal Parting Blade Holder BXA-7

Universal Parting Blade Holder BXA-7
www.aloris.com

The cutoff blade:

SGIH 26-4C-B7 CUT-OFF BLADE

SGIH 26-4C-B7 CUT-OFF BLADE
www.aloris.com



Also, is the wedge-grip proprietary to Aloris, or does the blade accept inserts from other insert makers?

Tony.
 
I'd get the GTL ("Left"), but it probably doesn't make a difference since you will still machine the end of the barrel you part off. (The difference is that the 8* lead angle should leave the tit on the bit of metal to the right of the tool, and a clean face on the left.) The GTN ("Neutral") guarantees you a burr wherever you don't want it... ;-)

I'm curious why you're parting? I've done a lot of barrel work, but never had need to part one.

GsT
 
Thanks! I sometimes get unfinished barrels that have an extra inch on the crown that I have to cut off and reface and re-crown. These are M14 barrels.

See the extra material on this barrel just forward of the threads:
ySfoJ7C.jpg


Now see how much I cut off to make the proper crown that will accept a flash suppressor.
PQof4VR.jpg


pdNjDU1.jpg


I also cut the front end off old M14 barrels to make jigs for things like flash suppressor reaming:
Jf5PGCB.jpg


I also make jigs for gas cylinder welding. The jig keeps the front band and gas cylinder in alignment while they are welded together.
HTfgnJD.jpg


the more jigs I have, the more cylinders I can have welded without having to remove hot jigs from welded parts. It saves time when I visit my welder. I have three right now, but on my last visit, I did eleven and it was cumbersome having to remove work with hot parts.

I also have a Kreiger barrel blank that I need to cut to length.

I also cut old AR-15 barrels or other steel parts to make steel pillars for pillar-bedding rear lugged M14's or bolt action rifles. I bore the sections out for 1/4-28 screws.
PGglv5E.jpg


82mWPPT.jpg


W1JP2eb.jpg


I can't tell you how many times I needed a parting tool only to have to cut a pilot groove and use a hacksaw to cut through steel.

Tony.
 
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Wow, that's a wide insert for barrel parting. I use a 2 different BXA-7 holders, one with a Shars GTN-2 and one with Shars GTN-3 width insert and both have no problem parting barrels. The 2mm and 3mm GTN inserts are < $2 each.
 
I'll sometimes use a parting tool to cut the muzzle end, but the horizontal band saw is so much easier for me. Put it in and walk away until it's done.
GeneT45 said:
I'd get the GTL ("Left"), but it probably doesn't make a difference since you will still machine the end of the barrel you part off. (The difference is that the 8* lead angle should leave the tit on the bit of metal to the right of the tool, and a clean face on the left.) The GTN ("Neutral") guarantees you a burr wherever you don't want it... ;-)

I'm curious why you're parting? I've done a lot of barrel work, but never had need to part one.

GsT
Click to expand...
Horizontal band saw for me...much easier to trim an inch off the muzzle end of blanks.
I use a somewhat similar spider setup, but I prefer to keep cuts/tool pressure light so I'll use the saw before setup.
Many ways to skin the cat with most barrel ops, just my preference.
 
I have a horizontal bandsaw and 2 Milwaukee porta-bands and still usually part in the lathe. I parted a 1.25" heat treated 416SS blank yesterday at 750 RPM with the GTN-2 insert, autofeed of 0.004" feedrate, smooth as silk.
 
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Bandsaw for me too. It occurred to me that there is one place I might use a parting tool doing barrel work,though I've never had to do it. In re-barreling older rifles (notably Mausers and Enfields) I've heard of using a parting tool near the breach end of the barrel, right up at the action, in order to get them to loosen up enough to remove the old barrel.

I personally favor narrower parting tools - and that means HSS. I think the narrowest insert parting tool I've found is right around 0.07x" (I don't recall exactly).

In any case, I think either of those inserts will work for what @TonyBen is doing.

GsT

ETA: Where were you when I lived in Forest Grove and had the M1A from hell? (I did finally get it running nicely.)
 
Thanks again for the info! I moved to Florida in 2022. I live right between Orlando and Tampa.

GsT, sorry we never met up in Oregon. I would have helped, for sure! I was in Beaverton, then North Plains.

I'll order those inserts.

Tony.
 
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