Proper Cutoff Blade

[BanjoDude]

In another thread, I was warned that the style cutoff blade I have is dangerous, in that when it breaks, it spits the back half backward. That's something I definitely don't want with the shop full of classic cars.... Is there another style that's recommended over these? I see that Shars has p/n 202-9575 that holds an insert. Is that a better option? Something else altogether?

 

[Ulma Doctor]

I use this type of holder

I broke the tool one time, but it was not catastrophic
It was my fault for pushing too hard without adequate cutting fluid in 304 stainless

If you are cautious , keep a sharp edge, add cutting fluid (when necessary), limit your stick out, and keep the tool on center , there is no reason to not use it.

Insert cut offs are great for some applications, explore them .
You’ll need a rigid machine that can turn high spindle speeds to use them as intended .

Good luck with whatever way you decide

 

[WobblyHand]

I have never heard of that. Is that a 1 or two piece blade? Mine, which look identical to the picture above are a single piece. The only time I have ever broken a blade is when I dropped the tool holder and blade onto concrete. HSS cut off blades are perfectly matched to smaller (OXA) lathes.

It also appears that the blade stick out is rather large above. Typically, it is adjusted to no more than what is needed which is just slightly longer the radius of the piece you are parting. So if parting a 1" diameter piece, the stick out is 1/2" (the radius) plus maybe 1/8". Excess stick out can cause problems.

Personally, I wouldn't be worried about using that kind of blade. In the past four years I've not found a need to use insert cut offs, because HSS cut off blades work well enough.

Some materials like 304, as mentioned by @Ulma Doctor, will work harden if not using the right technique. I have burned a blade cutting 304 once. If you let 304 rub rather than cut, the steel gets very hard.

 

[benmychree]

That is a poor tool holder, it provides no back rake that promotes free cutting.

 

[sycle1]

Its more the cut off tool Holder that is at fault, they don't put enough pressure on the cut off tool blank to hold it still, bad design. Chinesium
I have had the cut off tool fly out the back of the holder like a gun and lookout if you are in the way.

 

[GrifterGuru]

@BanjoDude

Not sure if something like this would suit your needs, but I have been using it for a while. I have seen a couple of different sizes available, though it is more the "block" that is the useful part more than the cut-off blade itself..


The block itself mounts into a tool holder.

The top of the block clamps along the legth of the cut-off blade. I have masked the name of the supplier as that is just info that is neither here nor there at this point in time.

 

[BanjoDude]

That is a poor tool holder, it provides no back rake that promotes free cutting

There are two versions of this same holder - one with back rake and one without. I assumed that the rake on the tool itself would help with that, no? I'm totally new to this. The problem I'm fighting is that my tool post is on the high side with no apparent way to lower it without milling the top off of the slide a bit. I may find that I need to bite the bullet and do that to get it lower.

 

[mmcmdl]

The top of the block clamps along the legth of the cut-off blade. I have masked the name of the supplier as that is just info that is neither here nor there at this point in time.

Looks like an Iscar or similar . Great for 12" lathes and up I would say . They want to cut , not rub .

 

[RaisedByWolves]

That is a poor tool holder, it provides no back rake that promotes free cutting.

That should be ground into the blade for use.

I’ve broken dozens of cutoff blades and never saw anything fly back at me.

Fly off in all directions? Sure.

 

[WobblyHand]

The advantage of the original tool holder is that one doesn't need to adjust the tool height if you increase the cut length. For new guys, it's hard to remember how to recenter the blade at spindle height.

Remember we're talking about OXA tooling, it doesn't have much beef to it to have the fancier features and the price point also tends to reduce features. But it's perfectly adequate for it's intended use, IMHO. Usually there are other more significant limitations to the lathe platform. Fix those via adjustments, and you'll find this class lathe works fine within it's limitations. Just don't expect the same level of capability as a full size industrial machine because that's not going to happen. However, if you stay within it's performance envelope, you can do some nice work.