machinist@lists.ibiblio.org
Subject: Machinist
List archive
[machinist] Disk sander for shaping carbide? - good thread on carbide tooling & sharpening it
- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] Disk sander for shaping carbide? - good thread on carbide tooling & sharpening it
- Date: Wed, 26 Feb 2014 09:09:19 -0500
http://www.practicalmachinist.com/vb/general/disk-sander-shaping-carbide-280909/
Thread: Disk sander for shaping carbide?
-
Disk sander for shaping carbide?
I am just a casual machinist, I have a south bend lathe in my motorcycle shop that I use for odd jobs we run it maybe once a week for a few hours. A lot of the time we are modifying fairly hard steel parts and some aluminum. I have been using brazed carbide bits from American carbide with a AXA QCTP. I would buy a tool grinder but it would take 50 years to pay for itself no more then we use.
I have a few bits that have a dull edge and was thinking is it possible to grind them on my belt or disk sander? The disk sander is nice because I can set the table and guide to the angle I need. I tried to use a AO 220 grit 3m disk and it polished up the carbide a touch but barley removed any material before striping the grit off the disk. Has anyone tried an Silicon carbide PSA disk? -
Carbide is going to eat a sanding disc up and also the disc will give a radiused edge instead of a hard flat surface like you will get from a grinding wheel. Just get some green wheels for a bench grinder. It's not the ideal way to sharpen carbide (I like to liken it to sharpening your pocket knife on the sidewalk), but it is serviceable.
Unless the parts you are modifying are truly hardened (induction hardened material, case hardened or nitrided), you can probably save yourself a lot of time and money by using High Speed Steel bits instead of carbide tooling. Especially on aluminum, you can't run a SB fast enough to justify carbide and the HS will not gum up as bad. Main thing is to know your speeds when it comes to cutting steel with HSS bits. You want to be running between 50 and 100fpm on the surface speed to avoid burning the tool up. You'll find your spindle speed is lower, but you can take a deeper bite and up the feed rate a LOT when using HSS versus carbide on a low powered lathe like a SB. You will take a lot longer per pass, but you can remove about eight times more metal per pass with HSS. You sharpen HSS on a plain old gray bench grinder wheel. -
02-26-2014, 02:17 AM #3
- Join Date
- Oct 2005
- Location
- Ogden, IA
- Posts
- 649
If you insist on carbide, might try getting yourself a coarse steel-backed diamond wheel that you can put on a bench grinder to rough out your carbide tool and then you'll also need a smooth steel wheel (can make it easily enough yourself) that you can apply lapping paste to in order to polish your carbide to a shiny finish once you're past the roughing phase.
You may also find it worthwhile to invest in a diamond embedded sharpening stone (I have one from Diamond Materials Technology that works pretty well) so that you can do minor sharpening on the machine without pulling the tool holder out. -
02-26-2014, 03:05 AM #4
- Join Date
- Jul 2004
- Location
- N. GA- 33.992N , -83.72W usa
- Posts
- 2,219
my belt grinder works much better for grinding and touching up carbide tools and inserts(non-coated) than my pedestal grinder w/ a green wheel.
i'll rough grind w/ a 60 grit SC belt ,and finish up w/ a 150 grit SC belt (on a 1.5hp Somaca wet/dry 106" x 4" machine w/ a flat platen ) .
if you must use a green wheel , i'd suggest a 120 grit , and dress it often . -
02-26-2014, 04:22 AM #5
- Join Date
- Sep 2011
- Location
- Mid-Atlantic USA, South China
- Posts
- 9,352
For rough shaping, on low/no budget, you'll get faster removal with some of the wheels available for common angle-grinders. Grinder can be grasped in a stout-enough vise or can be worm-gear clamped to a 2-by in turn Cee-clamped to the edge of the bench.
Originally Posted by bugman53
I am just a casual machinist, I have a south bend lathe in my motorcycle shop that I use for odd jobs we run it maybe once a week for a few hours. A lot of the time we are modifying fairly hard steel parts and some aluminum. I have been using brazed carbide bits from American carbide with a AXA QCTP. I would buy a tool grinder but it would take 50 years to pay for itself no more then we use.
I have a few bits that have a dull edge and was thinking is it possible to grind them on my belt or disk sander? The disk sander is nice because I can set the table and guide to the angle I need. I tried to use a AO 220 grit 3m disk and it polished up the carbide a touch but barley removed any material before striping the grit off the disk. Has anyone tried an Silicon carbide PSA disk?
But don't cite me as a source, please. It is a shade-tree technique if ever was.
It DOES work if you are patient, have a good hand, but the result is pretty ugly unless you have a diamond-abrasive wheel to clean it up with afterwards.
I have several such, of course.. But mostly just go and use HSS so as to not have to deal with carbide atall..
Bill -
02-26-2014, 04:30 AM #6
- Join Date
- Jun 2006
- Location
- Munich / Germany
- Posts
- 1,732
-
02-26-2014, 04:53 AM #7
- Join Date
- May 2011
- Location
- Texas
- Posts
- 2,585
A diamond tile cutting wheel from the hardware store in a die grinder will put a razor edge on them.
You can also get cermet inserts which will work fine on your toy lathe. -
On a south bend ??? Originally Posted by Nick Mueller
Tool up, buy inserts!
Nick
Come on
Inserttooling cost more as the lathe
Peter from holland -
I would go with insert tooling, Can be bought for cheap on ebay. However, if you still want to grind, this is the way to go.
6 x 3 8 x 1 1 4 inch D1A1 Diamond Wheel | eBay
It would probably last you a lifetime. I use this brand, the binder does not break down like the premium wheels. You would just have to make an adapter to put it on a 6" grinder. -
What ever type of Diamond wheel you buy remember it should have some way of dripping or spraying water on it,Do Not grind on a Dry Diamond wheel.Not talking about cutoff wheels true grinding wheels. Originally Posted by jamesu229
I would go with insert tooling, Can be bought for cheap on ebay. However, if you still want to grind, this is the way to go.
6 x 3 8 x 1 1 4 inch D1A1 Diamond Wheel | eBay
It would probably last you a lifetime. I use this brand, the binder does not break down like the premium wheels. You would just have to make an adapter to put it on a 6" grinder. -
02-26-2014, 08:17 AM #11
- Join Date
- Sep 2011
- Location
- Mid-Atlantic USA, South China
- Posts
- 9,352
Nah. SB's are seriously overpriced, so .... Originally Posted by peterve
On a south bend ???
Come on
Inserttooling cost more as the lathe
Peter from holland -
Originally Posted by peterve
On a south bend ???
Come on
Inserttooling cost more as the lathe
Peter from holland
Naaa, people really love them and spend lots of pretty pennies for them it seems like.
If you want inserts, Curt at latheinserts.com sells some nice 'hobby lathe' kits that work very well and the aluminum inserts are great.
HOBBY LATHE KIT
Reply
- [machinist] Disk sander for shaping carbide? - good thread on carbide tooling & sharpening it, Lawrence London, 02/26/2014
Archive powered by MHonArc 2.6.24.