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View Full Version : Cutting lathe toolbits to size... dremel?



caveBob
06-07-2012, 11:41 PM
I need to cut some round M2 and WKE45 (11% cobalt) toolbit stock for a few boring bars and threading tools. Mount in drill press, spin ~slowly while cutting needed lengths with a dremel? How do you cut this stuff to minimize waste... hacksaw aint gonna cut it... :)

TGTool
06-07-2012, 11:52 PM
Dremel works for me with the little abrasive cutoff wheels. You don't usually have to cut all the way through, but at some point you can give it a whack, separate the parts, then go hunt around on the floor for the part you just cut off. :D I usually just put the blank in the vise, sometimes turning it over to cut part way from both sides.

sch
06-07-2012, 11:55 PM
The very thin abrasive cutters on dremel react poorly to any miniscule
angle change and break easily, they will work if tediously so. A little
larger grinder with 1/16" wide abrasive wheels 3-4" in diameter will
be more robust and cut a lot faster. If your M2 is under 0.25" diameter
it would not matter that much. Just lay in a supply of 25 or 50 dremel
abrasive cutoffs and wear substantial eye protection.

Dr Stan
06-08-2012, 12:25 AM
You don't usually have to cut all the way through, but at some point you can give it a whack, separate the parts, then go hunt around on the floor for the part you just cut off.

Just wrap it in a rag before you put it in a vice. Then whack it and you won't have to hunt for it.

BTW, a 3" cut off wheel in an automotive type pneumatic cut out tool works quite well. Something like this one: http://www.harborfreight.com/air-tools/specialty-air-tools/3-inch-high-speed-air-cutter-47077.html

TGTool
06-08-2012, 12:32 AM
I might also mention I've used the plated diamond Dremel wheels for cutting off carbide blanks. Not very accurate since it's a hand operation but it's nice to know any way at all of reshaping or cutting carbide. The green wheels will help shape a cutter though they're a real chore, but they're no help at all for small cutting off.

caveBob
06-08-2012, 01:10 AM
Ok thanks guys, I'll give the dremel a go tomorrow then.

That pneumatic tool looks like it would be a great option... if I had a compressor. Need to educate myself on what to look for without breaking the bank or buying "just cheap" soon followed by what I should have gotten the first time around.

darryl
06-08-2012, 01:45 AM
Several years ago I built myself a pedestal style motorized cutoff blade machine. It can use up to a 12 inch diameter blade. One of the handiest tools in the shop for just such things. I cut a lot of music wire on it, and I use it to form and shape all kind of tools from that inch to inch and a half wide HSS bandsaw blade I got for cheap.

The machine takes two blades, one above the other, and each has its own table. I pivot the machine towards me and the upper wheel is accessible- pivot it away and the lower wheel is usable. I have one disc made for stainless on it, and the other disc is what was called a super disc- it's coated both sides with carbide so you can work with the edge or either side. I do a lot of shaping with it, but because it's flexible I have to take into consideration the angles I'm making on something. But it's my favorite cutoff disc. I could not go back to the 3 inch discs on an angle grinder, let alone a dremel, though each of those certainly has its uses.

Fasttrack
06-08-2012, 02:13 AM
Several years ago I built myself a pedestal style motorized cutoff blade machine. It can use up to a 12 inch diameter blade. One of the handiest tools in the shop for just such things. I cut a lot of music wire on it, and I use it to form and shape all kind of tools from that inch to inch and a half wide HSS bandsaw blade I got for cheap.

The machine takes two blades, one above the other, and each has its own table. I pivot the machine towards me and the upper wheel is accessible- pivot it away and the lower wheel is usable. I have one disc made for stainless on it, and the other disc is what was called a super disc- it's coated both sides with carbide so you can work with the edge or either side. I do a lot of shaping with it, but because it's flexible I have to take into consideration the angles I'm making on something. But it's my favorite cutoff disc. I could not go back to the 3 inch discs on an angle grinder, let alone a dremel, though each of those certainly has its uses.


Would you mind starting a thread with some pictures and a short write up about it? I've been meaning to build something like this for years. I'm not at a point where I can even think about taking on any new projects at the moment, but I'd like to see yours and book mark it for the future projects list...

camdigger
06-08-2012, 02:52 AM
In my shop, i use the dremel with a cutoff blade, or a 4 1/2" angle grinder with a 1/16" cutting wheel.
Cut just over 1/3 from either side, then grip the end with a locking plier and snap off.

No whacking or flying pieces to chase through the archaeological dig of project rubble around the vise....

Duffy
06-08-2012, 11:26 AM
You can buy fiber-reinforced cutoff wheels for a Dremel. They are more forgiving of hand-eye control for free-hand work. A bit thicker than the un-reinforced type but they work well.

rowbare
06-08-2012, 12:26 PM
That pneumatic tool looks like it would be a great option... if I had a compressor. Need to educate myself on what to look for without breaking the bank or buying "just cheap" soon followed by what I should have gotten the first time around.

HF has just released an electric version of that cutoff tool: http://www.harborfreight.com/120-volt-3-high-speed-cut-off-tool-68523.html

bob

Ian B
06-08-2012, 12:57 PM
I'd go with exactly what Camdigger says; cheap electric 5" angle grinder with a 2mm cutoff disk, grind partly through all around, snap it off.

Ian

sch
06-08-2012, 01:20 PM
Pneumatic tools require a substantial compressor to operate, the pancake
variety for nail guns will have about a 3% duty cycle with even a small
pneumatic tool, such as a 3" cutoff grinder. Better to get a cheap (HF)
electric grinder with a 3-4" cutoff capacity. The diamond dremels don't
break as easily but high speed cutting of steel with diamond tool is not
very fast and can wear out the tool. They are intended for non ferrous
ie ceramic/glass cutting.

armedandsafe
06-08-2012, 02:30 PM
The HF grinder looks pretty nice. For what it's worth, I bought the SKIL 4 1/2" yesterday for $35 at WalMart.

Pops

Peter.
06-08-2012, 02:39 PM
I'd go with exactly what Camdigger says; cheap electric 5" angle grinder with a 2mm cutoff disk, grind partly through all around, snap it off.

Ian
I use a 18 discount-store angle grinder fitted with 1mm thin discs. Cuts almost anything. Even cuts 316 stainless with no burr.

demerrill
06-08-2012, 04:55 PM
Harbor Freight used to carry a swing-arm holder for angle grinder that, while chintzy, worked adequately for tasks like this. I no longer find it at their on-line site, but here is a European link to a similar one:

http://www.baumarktwissen.eu/Medien/mdb/data/en/24063/24069/24064/cutoff_stand.html

David Merrill

ak95xj
06-08-2012, 05:24 PM
The HF grinder looks pretty nice. For what it's worth, I bought the SKIL 4 1/2" yesterday for $35 at WalMart.

Pops

I have a HF one and a Dewalt..I brought the Dewalt to work and use the HF at home for things like this all the time..It works fine (bogs down a little during heavy grinding) , for under 20$ you cant go wrong..I only use my dremel if its something that an angle grinder wont fit into, an angle grinder completely blows them away..

Paul Alciatore
06-08-2012, 06:42 PM
I am wondering if a small, table style abrasive cutting saw could be made with a Dremel tool for power and the small abrasive disks, both the small, fragile ones and the larger, reinforced ones. A table and miter arrangement would make the cuts more precise and decreases the chances of breaking the disks.

The main problem I see is the diameter of the Dremel tool vs. the diameter of the abrasive disks. This prevents any real length of stock from fitting. Several ideas come to mind: a long extension for the spindle that holds the abrasive disks or a right angle gear drive (at 10K RPM?) or a belt drive (again at 10K RPM) or perhaps a friction drive with a rubber belted wheel on the Dremel and a metal drum of the same diameter on the arbor. The arbor bearings would also be a problem: they need to provide a small offset from the table top. Miniature BBs? An air bearing would be neat! But air would need to be on FIRST. Or what?

I wonder if it is a useful project. Any takers? No way I can do it at the present time. But it's a neat idea. And you could do a lot with hardened tool bits with it. Table could tilt +/-15 degrees for cutting relief and rake angles. Miter gauge for the angles of the cut.

caveBob
06-08-2012, 07:48 PM
Harbor Freight used to carry a swing-arm holder for angle grinder that, while chintzy, worked adequately for tasks like this. I no longer find it at their on-line site, but here is a European link to a similar one:

David Merrill

Funny... I just went to the link that rowbare posted and on that page I saw a link to this: 2" Bench Top Cut-Off Saw (http://www.harborfreight.com/bench-top-cut-off-saw-42307.html)

<EDIT> nevermind, right idea though...

demerrill
06-24-2012, 11:40 PM
Just ran across a reference to this Grizzly version of the angle grinder stand:

http://www.grizzly.com/products/4-1-2-Angle-Grinder-Stand/G8183

David Merrill

caveBob
06-25-2012, 12:13 AM
Just ran across a reference to this Grizzly version of the angle grinder stand:

http://www.grizzly.com/products/4-1-2-Angle-Grinder-Stand/G8183

David Merrill

Thanks for the link demerrill, sure making me think "wonder what I could cobble together from scraps" though. The price sure seems fair too...

Was looking at Lowes (http://www.lowes.com/ProductDisplay?partNumber=317411-70-DW8424B5&langId=-1&storeId=10151&productId=3179041&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1) for the cutoff wheel:

http://images.lowes.com/product/converted/885911/885911206037xl.jpg

wouldn't .045" be a little on the thin side?

lwalker
06-26-2012, 02:42 PM
I used to have one of those. Two, actually. I lent the first one to a friend and he burned it out and bought me a new one. It works fine for the price, but you have to watch the duty cycle: when the first one burned out, he was cutting a lot of pieces continuously and noticed it was getting hot, but kept going.

The vise doesn't clamp small pieces well, but overall it's worth the $29.95.



Funny... I just went to the link that rowbare posted and on that page I saw a link to this: 2" Bench Top Cut-Off Saw (http://www.harborfreight.com/bench-top-cut-off-saw-42307.html)

<EDIT> nevermind, right idea though...

flathead4
06-26-2012, 04:20 PM
Cutting lathe toolbits to size... dremel?

Snap them off with your dentures...

Tom

Peter.
06-26-2012, 06:15 PM
wouldn't .045" be a little on the thin side?

No, they are fantastic cutting discs. After you have used one of those you won't want to go back to the regular thickness disc.

rohart
06-26-2012, 08:39 PM
I've started to use those thinner discs. They are very good, until you tears the edge. Then you need to cut gently for a while to restore circularity.

I just jam my angle grinder in the bench vice, stand behind it with the disc turning away from me, reach over, holding the tool material, and pull it carefully into the disc. I attack the tool rod from different sides. I can cut anything from 1/8th to 1/2 inch that way. And there's so little temperature rise I can get through 1/4 at one sitting. I always stop when there's a little left and snap the last bit.