1 mm M2 or similar blanks anyone?

[Mark Hepburn]

I'm wanting to make a parting tool that is thinner than my 1/16".

I'm taking a class with Steven Kennard this November, and we were talking at the symposium and he mentioned wanting one thinner than the 1/16 for his work. Makes sense to me but the tool doesn't seem to exist. Therefore I thought I'd try my hand at making a couple of them. Just a flat blade, full tang, a handle and bras rivets and Bob's your uncle. Hopefully.

Anyway, I've been looking all over the tubes of the interweb and can't find anything like a piece of flat M2 in that thickness. There's other stuff: D2, A2, and some other and I did find some CPM 3V in a .o48" blank.

Not being a metal guy I don't know if the CPM 3V would be a good candidate. Here's the information from Crucible Materials site:

CPM 3V is a high toughness, wear-resistant tool steel made by the Crucible Particle Metallurgy process. It is designed to provide maximum resistance to breakage and chipping in a high wear-resistance steel. It offers impact resistance greater than A2, D2, Cru-Wear, or CPM M4, approaching the levels provided by S7 and other shock resistant grades. CPM 3V is intended to be used at 58/60 HRC in applications where chronic breakage and chipping are encountered in other tool steels, but where the wear properties of a high alloy steel are required.
Nominal Composition
Carbon 0.80%
Chromium 7.50%
Vanadium 2.75%
Molybdenum 1.30%
Typical Applications
Stamping or Forming Tools Punches and Dies
Blanking Tools Fineblanking Tools
Industrial Knives and Slitters Shear Blades
Scrap Choppers Rolls
Plastic Injection and Extrusion Feedscrews
The wear and toughness properties of CPM 3V make it an excellent alternative to shock-resistant steels such as S7 or A9, where they typically wear out too quickly, but where grades such as A2, CruWear, or CPM M4 tend to fail by breaking or chipping. CPM 3V offers the highest impact toughness of any tool steel with this range of wear resistance.

So it seems to me that this might be a good way to go, but I'd appreciate any input from those of you with metallurgical expertise.

Thanks!

 

[Bill Boehme]

Yesterday I got two deep cuts in my left index finger from using a thin parting tool that is just a bit under a sixteenth inch thick on a large diameter spindle (about 5 inches). In retrospect, the injury could have been much worse. Thin tools flex. They can be grabbed in the thin kerf of the spinning wood and yanked out of your hand faster than you can imagine. Or, if you are holding on tightly, it might just yank your hand right into the wood.

I had opened up the kerf to give me plenty of working room I thought, but the tool was flexing with the long overhang. I suppose that there was just enough twist to run the tool into the wood all the way up to the handle. My forward hand that was helping to guide the tool in the cut got a nasty gash. As if that wasn't bad enough, I did it again a few minutes later. Finally, I decided that maybe I ought to reevaluate what I was doing.

If you want thin steel, the best that I have found is a Veritas flexible flush cut Japanese style pull saw designed for flush cutting dowels. I have safely used it as a super-thin parting tool on very small items with the lathe running backwards. I wouldn't use it on anything larger than about a half inch diameter.

 

[john lucas]

thin tools need to be tall in order to help keep them from flexing. I have an old bandsaw blade that is about 1/16" wide and maybe an inch tall. It doesn't flex much. I also have an old paring knife that is thinner but only about 4" long. What do you need thinner for. To cut deeper than 2" with a blade that thin is challenging. You know you should always make 2 passes with a parting tool to allow for clearance so the tool won't get jammed. this of course widens the kerf that you are trying to keep very thin. To help with this problem what I do is to widen then kerf on the inside only. In other words I make the first cut about 3/8" to 1/2" deep. Then I use this opening as a sort of fulcrum and move the tool handle left, insert the tool into this opening and make another cut. Then move the tool handle to the right, insert the tool through the same opening and make a cut. So the cut is getting wider on the inside but not at the opening of the cut. This way the blade can go in very deep without binding and I haven't made the initial cut any wider. Most of the time on boxes anyway the inside will be hollowed so you aren't worried about grain match there. Only at the lip. doing it this way I have made the kerf as narrow as possible on the outside where the grain match will be most noticeable.
I do have very very thin parting tools for my ultra miniature work. However those only go into the work no more than about 2mm max so they can be quite thin.

 

[hockenbery]

If you want thin steel, the best that I have found is a Veritas flexible flush cut Japanese style pull saw designed for flush cutting dowels. I have safely used it as a super-thin parting tool on very small items with the lathe running backwards. I wouldn't use it on anything larger than about a half inch diameter.

I use saws for thin cuts too running the lathe backwards.
Mostly I use hacksaws with the blade mounted backwards.
For extra thin I use a scroll saw. While the scroll saw works I break the blades fairly often but they are cheap.

Mostly I have used this for cutting two pieces where I want the grain to align.

IMHO a saw is the safest ( and possibly the most effective ) way to make a thin cut on a rotating object.

 

[billooms]

You can buy the thin blanks that are used on metal lathes. They come in 1/16", 5/64", or 0.040" width:

http://www.littlemachineshop.com/products/product_related.php?RelatedID=1147449330

As Bill Boehme says, they tend to grab at the top and twist if you use them hand-held. I use them occasionally, but only on small diameter pieces.

 

[Douglas Ladendorf]

The teeth of a saw have a set wider than the blade thickness which would help prevent binding. A thin blade would have less to bind and support from both sides would give it more strength. I would think a fret saw with lathe in reverse would work well.

 

[Bill Boehme]

... To help with this problem what I do is to widen then kerf on the inside only. In other words I make the first cut about 3/8" to 1/2" deep. Then I use this opening as a sort of fulcrum and move the tool handle left, insert the tool into this opening and make another cut. Then move the tool handle to the right, insert the tool through the same opening and make a cut. So the cut is getting wider on the inside but not at the opening of the cut. This way the blade can go in very deep without binding and I haven't made the initial cut any wider...

I also widen the kerf on the inside, but doing this is what led to my problem. As the cut was getting close to the center of this 5" diameter spindle, the wood was able to flex enough to pinch the parting tool at the outer edge where the kerf was only slightly wider than the blade. If the blade were even thinner with a thinner kerf at the outer edge, then the flex in the wood to pinch the blade would be even less. My conclusions are to keep the tool pressure very light when the wood gets down to 3/4" diameter on large pieces and also make the outside kerf much wider so that it can't pinch the tool and pull you into the work.

Mark, I don't think that for a parting tool the type of HSS matters. Just make sure that the blade is plenty tall to resist twisting like John said and unless you are thinking of parting very small pieces, my opinion is that 1 mm is bordering on being too thin. There is probably a reason that commercially available parting tools aren't any thinner than 1/16", which is ~ 1.6 mm.

 

[hockenbery]

Bill

the same pinching happens with saw too.
When the center gets below 1/2" in diameter or so it flexes and the the outside edges close up on the opposite side and will grab the saw blade.

But! The saw will work a really slow rpm. As I get close to 1/2" I slow way down
I usually finish the last 1/4" at 0 rpm of the lathe and cut through with the saw by hand.

If both ends will be hollowed out the final parting can be done with a twist.
The twist will tear fiber out from both sides sometimes more than a 1/2" deep.

Al

 

[Mark Hepburn]

Yesterday I got two deep cuts in my left index finger from using a thin parting tool that is just a bit under a sixteenth inch thick on a large diameter spindle (about 5 inches). In retrospect, the injury could have been much worse. Thin tools flex. They can be grabbed in the thin kerf of the spinning wood and yanked out of your hand faster than you can imagine. Or, if you are holding on tightly, it might just yank your hand right into the wood.

I had opened up the kerf to give me plenty of working room I thought, but the tool was flexing with the long overhang. I suppose that there was just enough twist to run the tool into the wood all the way up to the handle. My forward hand that was helping to guide the tool in the cut got a nasty gash. As if that wasn't bad enough, I did it again a few minutes later. Finally, I decided that maybe I ought to reevaluate what I was doing.

If you want thin steel, the best that I have found is a Veritas flexible flush cut Japanese style pull saw designed for flush cutting dowels. I have safely used it as a super-thin parting tool on very small items with the lathe running backwards. I wouldn't use it on anything larger than about a half inch diameter.

Hey Bill. I actually used my Japanes pull saw last night for that very purpose. Just to cut down a spindle I was parting off (and did the same thing - about the last 1/2").

I understand the issue about flexing but this would be for small work.

 

[Mark Hepburn]

thin tools need to be tall in order to help keep them from flexing. I have an old bandsaw blade that is about 1/16" wide and maybe an inch tall. It doesn't flex much. I also have an old paring knife that is thinner but only about 4" long. What do you need thinner for. To cut deeper than 2" with a blade that thin is challenging. You know you should always make 2 passes with a parting tool to allow for clearance so the tool won't get jammed. this of course widens the kerf that you are trying to keep very thin. To help with this problem what I do is to widen then kerf on the inside only. In other words I make the first cut about 3/8" to 1/2" deep. Then I use this opening as a sort of fulcrum and move the tool handle left, insert the tool into this opening and make another cut. Then move the tool handle to the right, insert the tool through the same opening and make a cut. So the cut is getting wider on the inside but not at the opening of the cut. This way the blade can go in very deep without binding and I haven't made the initial cut any wider. Most of the time on boxes anyway the inside will be hollowed so you aren't worried about grain match there. Only at the lip. doing it this way I have made the kerf as narrow as possible on the outside where the grain match will be most noticeable.
I do have very very thin parting tools for my ultra miniature work. However those only go into the work no more than about 2mm max so they can be quite thin.

Hi John. The truth is, that I want to try it mainly because that's what Steven Kennard wants to use for some of his work (not the teardrop boxes but some of the other stuff). So I thought, what the heck. He said that he finds the 1/16" a bit thick. And truth is, I'd like to try my hand at making a tool too.

I have a 1/8" parting tool from Doug Thompson that I use an awful lot and I do use relief cuts when parting off. I also have a Taylor 1/16" parting tool that I use for smaller things and you're right, it can present a challenge even though the blade is about 1 1/4" wide.

I also use a pull saw for smaller tenons and don't like how it flexes - but it is a long blade. I'm thinking of a tool with about a 3" blade length max, full tang, in a 9" handle or so.

 

[Mark Hepburn]

I use saws for thin cuts too running the lathe backwards.
Mostly I use hacksaws with the blade mounted backwards.
For extra thin I use a scroll saw. While the scroll saw works I break the blades fairly often but they are cheap.

Mostly I have used this for cutting two pieces where I want the grain to align.

IMHO a saw is the safest ( and possibly the most effective ) way to make a thin cut on a rotating object.

Al, I've used my band saw with a 1/4" blade on it but changing it back for resawing and blank rounding is a hassle, but I hadn't considered my scroll saw.

I don't have any objection to a saw but the length is the issue because thin saw blades tend to flex more the longer they are.

 

[Mark Hepburn]

You can buy the thin blanks that are used on metal lathes. They come in 1/16", 5/64", or 0.040" width:

http://www.littlemachineshop.com/products/product_related.php?RelatedID=1147449330

As Bill Boehme says, they tend to grab at the top and twist if you use them hand-held. I use them occasionally, but only on small diameter pieces.

Bill, thank you. This looks like it just may be the ticket. But I've also thought maybe that Doug's post about a fret saw blade might be worth looking into. Still, I'm intent on making a thin tool. Forging ahead (pardon the pun) even if it may seem a bit dumb.

 

[Mark Hepburn]

The teeth of a saw have a set wider than the blade thickness which would help prevent binding. A thin blade would have less to bind and support from both sides would give it more strength. I would think a fret saw with lathe in reverse would work well.

Doug,

That's an appealing option. Almost like a veneer saw but longer. So the set of the teeth on a fret saw aren't flat? I found several that are sort of like a back saw, so if I found one with a blade width of about 1 1/2" and a back, then it would give me the ability to cut up to about 2" diameter or so.

Bill also pointed me to a source for cut off blades so I'm probably going to try both approaches.

Thanks!

 

[hockenbery]

Al, I've used my band saw with a 1/4" blade on it but changing it back for resawing and blank rounding is a hassle, but I hadn't considered my scroll saw. I don't have any objection to a saw but the length is the issue because thin saw blades tend to flex more the longer they are.

I use blades in saw frame. Like a hack saw and hand scroll saw(fret saw with the teeth facing the handle.
The turning wood puts tension on the blade I just have to hold the handle. And keep the blade straight to start the cut.
I haven't used a Japanese pull saw but it should work well too and is probably a lot quicker.

I prefer to saw think cuts rather than use a super thin parting tool.

Al

 

[Mark Hepburn]

I use blades in saw frame. Like a hack saw and hand scroll saw(fret saw with the teeth facing the handle.
The turning wood puts tension on the blade I just have to hold the handle. And keep the blade straight to start the cut.
I haven't used a Japanese pull saw but it should work well too and is probably a lot quicker.

I prefer to saw think cuts rather than use a super thin parting tool.

Al

Al, the thing about the Japanes pull saw is that the blade gums up pretty quickly so I find I have to keep removing it, degunking it and so on. Lathe on, Lathe off, etc.

 

[hockenbery]

Al, the thing about the Japanes pull saw is that the blade gums up pretty quickly so I find I have to keep removing it, degunking it and so on. Lathe on, Lathe off, etc.

You sawing wet wood?
I only use the saws on dry wood I might be making a box from.

Al

 

[Bill Boehme]

You sawing wet wood?
I only use the saws on dry wood I might be making a box from.

Al

Or could it be resinous wood and running the lathe too fast?

Al, is the frame that you are talking about a coping saw? They hold blades that look a lot like scroll saw blades (maybe because they are the same thing).

 

[Mark Hepburn]

You sawing wet wood?
I only use the saws on dry wood I might be making a box from.

Al

No, it's dry wood but the teeth are fine and with a flat set to the teeth, there's no way to clear the cuttings.

But I just took Dougs idea and used my veneer saw I don't have a fret saw so this was my next option. It works beautifully. Curved blade is a bit of help and it's like a back saw so rigid.

 

[Mark Hepburn]

Or could it be resinous wood and running the lathe too fast?

Al, is the frame that you are talking about a coping saw? They hold blades that look a lot like scroll saw blades (maybe because they are the same thing).

This little saw is what I used. Lee Valley. I almost never do any veneer work anymore and usually use a knife anyway so it's just settin'.

 

[Mark Hepburn]

Or could it be resinous wood and running the lathe too fast?

Al, is the frame that you are talking about a coping saw? They hold blades that look a lot like scroll saw blades (maybe because they are the same thing).

I might be running the lathe too fast. Is 3000 rpm too fast?

"Is that wrong? Because if someone had told me that was wrong..."



Seriously, I ran it at about 400 to cut.

 

[hockenbery]

Or could it be resinous wood and running the lathe too fast? Al, is the frame that you are talking about a coping saw? They hold blades that look a lot like scroll saw blades (maybe because they are the same thing).

Bill
Yes.
I might not use the correct name. I don't know if the different names have unique meanings.
Fret saw, coping saw, or hand jig saw seem to be different names for the same tool.
They all have a frame, a handle, thin blade, and a blade tensioning mechanism

Might depend on what you use it for
a coping cuts molding, a fret saw cuts inlay or intarsia and jigsaw cuts puzzle pieces.

Maybe someone knows of a proper nomenclature

Al

 

[Mark Hepburn]

Here are two different fret saws I found on the tubes of the interweb.

 

[hockenbery]

This little saw is what I used. Lee Valley. I almost never do any veneer work anymore and usually use a knife anyway so it's just settin'. <img src="http://www.aawforum.org/vbforum/attachment.php?attachmentid=8594"/>

Mark,
I only use a saw with the lathe running in revers so it pulls the saw away from me.
So I have to use a saw that cuts on the pull stroke. The hack saw and fret saw/coping saw/jigsaw can all have the blades installed to cut on the pull.
If anything bad happens like a broken blade it is going away from you.

The veneer saw probably cuts on the push.
I would use it with the lathe off only.


Al

 

[Mark Hepburn]

Mark,
I only use a saw with the lathe running in revers so it pulls the saw away from me.
So I have to use a saw that cuts on the pull stroke. The hack saw and fret saw/coping saw/jigsaw can all have the blades installed to cut on the pull.
If anything bad happens like a broken blade it is going away from you.

The veneer saw probably cuts on the push.
I would use it with the lathe off only.


Al

Good point. Thanks. I send enough to projectiles spinning off into the shop as it is no need to add more opportunities.

 

[hockenbery]

Here are two different fret saws I found on the tubes of the interweb. <img src="http://www.aawforum.org/vbforum/attachment.php?attachmentid=8595"/><img src="http://www.aawforum.org/vbforum/attachment.php?attachmentid=8596"/>

Like the one with the thin blade.
Don't need such a deep cutting one.

The attached photo looks like what I use and is like bills hot link.

Al

 

[odie]

Deleted......I see this idea has already been speculated upon......and not thin enough anyway.

 

[Bill Boehme]

Bill
Yes.
I might not use the correct name. I don't know if the different names have unique meanings.
Fret saw, coping saw, or hand jig saw seem to be different names for the same tool....

Yeah, I wouldn't "fret" about it. We'll manage to "cope" even if we don't know the right name.

 

[hockenbery]

Yeah, I wouldn't "fret" about it. We'll manage to "cope" even if we don't know the right name.

Mind if I scroll through that comment?

 

[Mark Hepburn]

Mind if I scroll through that comment?

Please feel free, Al. But then perhaps we should table the discussion so the band can move on?

If anyone else has any reciprocal feelings on the matter?

:-D

 

[Douglas Ladendorf]

Done on my "part."

 

[Mark Hepburn]

Good close, Doug.

 

[Gerald Lawrence]

Good close, Doug.

Well I guess I could say I "saw" this coming