Mystery cut-off tool holder

[Highpower]

Carbide cut-off tool holder (19-5) #4500409508
and
Blade (26-2) # 45000420418

No manufacturer markings anywhere. Any idea who makes them?
And what type/style inserts can be used in this blade?

[sasquatch]

Was there a pic Willie? I didn't get anything.

[PixMan]

I can usually help. but there's not enough to go with there.

What company are these coming from or is it an eBay auction or what? The 19-5 and 26-2 can indicate certain things (19mm = 3/4", and 26mm = 1"), so I'd bet the holder is a blade holder block that's got a 3/4" mounting square, and the blade is a 1" to 1.020" high that's about .075" wide. Chances are, just by virtue of overall popularity, common copying, and broad distribution that it's a blade for the now-discontinued Iscar GTL/GTN/GTR single-ended inserts in the 2.2mm width size. The inserts and blades will long be available from other sources.

All this is a wild guess with no photos, links or measurements.

[stevec]

No pics, it doesn't exist!

[Highpower]

Well I guess they don't exist then since I don't have them in front of me.

A friend of a friend was looking for a new home for them, and asking if anybody wanted them. The story is they came in unmarked packaging from McMaster-Carr (no surprise) and no identifying markings other than engraved part numbers on the tools.

I'll see if I can get some measurements through the grapevine, but as I only have AXA and BXA tool posts, if the holder is 3/4" it would be too large for my lathe anyway. Just my luck...

[EdK]

(01-04-2013, 10:17 AM)Highpower Wrote: Well I guess they don't exist then since I don't have them in front of me.

A friend of a friend was looking for a new home for them, and asking if anybody wanted them. The story is they came in unmarked packaging from McMaster-Carr (no surprise) and no identifying markings other than engraved part numbers on the tools.

I'll see if I can get some measurements through the grapevine, but as I only have AXA and BXA tool posts, if the holder is 3/4" it would be too large for my lathe anyway. Just my luck...

Those ones from McMaster are made by Newcomer. I bought a set a while back and had to return it because the blade holder was machine improperly. That was the first and only time I've ever had to return something to McMaster because of a defect.

Ed

[dallen]

cut a dovetail in them that will fit the tool post and use them, I have several 1 inch shanks that I have done that way or just mill em down so they fit in the holder with the insert at proper height.

[PixMan]

With quick change tool posts, there are 3 basic types of holders for parting tools.

The most common is the "Number 7" one that's included in most QCTP sets. It holds a HSS blade at an upward angle, and they are such a pain in the neck to keep adjusting the center height as you resharpen the tool. I swear those are among the worst holders, so fussy to get a good cutoff. When you finally get a blade sharpened in a way that it works and you don't get the crunching climb-up or chatter, you're so often reluctant to resharpen it because you're afraid it'll never work the same again. And usually, it doesn't.

Next you have the straight-across blades and the associated holder blocks for them. These can hold either HSS blades or insert blades, although the insert blades tend to be taller and it's hard to find HSS blades that size. There are two types of the holder blocks, one is like the one I believe Willie is rumoured to have, and those slip into a regular No.1 or No.2 holder block. The problem with those is that you're moving the cutting point further out and away from the support of the compound slide. These are like the ones I sold off:


The other type of blade holders, which is what I moved to, are the integral blocks like these:


That type keeps a parting blade as close as possible to the compand slide, and seem to be more rigid. The problem is that the #7-71, #7-71-32, #771's (all makers seems to use slightly different catalog numbers) are harder or IMPOSSIBLE to find for the smaller QCTP sets such as AXA-100 & BXA-200 sizes. Mine are CA-400, and I have seen some for the CXA-300 size QCTP's.

One other style of carbide parting insert holder is the "monoblock" style, meaning the square shank holding the insert fits directly into a No.1 or No.2 style block. I've got a couple that I use now & then. You can see the top view of one in this photo, the second one from the right.


Here's a side view of a smaller one for small diameter work:


The ones I hate the most and have had the most crashes with are the lantern tool post style, expecially those with the "flex" slot in them. I guess they put that slot in them because they 'expect" you to have the work climb up on the tool and snap off.

[Highpower]

I totally agree Ken, the #7 QCTP holders are a pain. Especially if you are using the cheap (alleged) "HSS" blades that usually accompany them. I did find that things greatly improved after I grooved my #7 holders to hold better quality "T" blades so that they are vertical. Still - it's usually a 50/50 chance that it will cut well without SOME sort of issue.

I have a question about the grind on the T-blade in your photo though.



It looks like the front of the blade was ground convex following the curvature of the grinding wheel. Does this not weaken the tip of the blade on a parting tool? Every one I have ever seen has a straight cut relief on the front edge of the blade. How does that work?

[PixMan]

Willie,

The HSS T-blade in the middle holder was ground like that by some unknown person at the shop who gave me the lathe. It's about 3/16" wide, and still dull. I sincerely doubt I'll ever even sharpen it, let alone use it. It was just a place-holder for the photo. Good eye!