Toolbits & Groove Cutting

[Maryak]

Garry,

IMHO, it's probably easier to measure the tool bit size rather than the groove size, so that's the way I would do it.

Best Regards
Bob

 

[vlmarshall]

... especially if you're making them thin, like a parting tool. Leave them full width, to make them stronger, cutting with the side is just going to flex them.
Plus, you can resharpen them without changing the profile.

 

[gmac]

I see your points - I need some that are in the 0.025 and 0.050 inch width range; fortunately the depth of cut is shallow. I'd be cutting square holes in a matter of speaking. It's the cylinder fins that un-nerve me with their deeper plunge cut!

So it's a bit like making piston/cylinder pairs then - make the hole first....then the piston :big: I''ll grind the bit, try the bit, measure the groove, grind the bit.....sneak up on it...

Thanks guys
Garry

 

[Jadecy]

This is relative to thin grooves but not exactly an answer to your question.

AR Warner makes a really nice indexable grooving tool with HSS inserts for $90. I bought one at Cabin Fever this year and love this little tool. It is more expensive than self ground bit from a HSS blank but If you are like me you don't have a precision tool grinder.

I have no affiliation with them other than REALLY liking this little tool.

http://www.arwarnerco.com/warner_products_kits_cutoff-groover_k21.html

 

[gmac]

Jadecy:

You've been looking over my shoulder ;D. An hour ago I finished grinding up a 1/4" HSS grooving tool 0.024" wide on a generic 6" grinder. I'm covered in black dust.

It wasn't till I'd finished that it dawned on me - "I've got to machine a cast iron piston ring to fit in that narrow a slot? I've read the drawing wrong.....nooo - yes it is a 0.0235" wide ring." (for Ron Colonna's Offy design) What have I got myself into ......

I like this AR Warner tool - even if I just bought the inserts. Thanks for the heads up.

Cheers
Garry

 

[Blogwitch]

If you know anyone with a surface grinder, you can just grind down to whatever width you like in a matter of minutes.

Just a parallel grind, and the only rake is a front one if using on brass or ali, but a bit of top rake as well if using for steel. I normally put one on either end of a bit of tool steel, just in case you break it (very rarely), then it is just a matter of flipping over and carrying on from where you left off.

My most used one is 0.025" by 3/8" long, and could part off 1/2" diameter bar with no problems. But I have made grooving tools as narrow as 0.010" and 1/4" long with great success.

Just two things to be noted. The tool has to go in perfectly square to the job, and after say 100 cuts in non ferrous, it might be time to make a new one. Because of no side rake or clearances, the width actually wears away, so if you have an old one, it is best to check the width before use.

Hope this has been of some use.

Blogs

 

[gmac]

Blogs

Unfortunately no one around with a surface grinder, and I loaded up the stone on my grinder yesterday. So I'm off to pick up a grinding wheel dresser today. The toolbits I have left to make are only short overhang so there will be less material to remove. Strangely I don't mind sitting outside at the grinder for long periods - if only I could be as patient with my machining!

Thanks for the assist.

Garry

 

[Marinesteam]

The Warner tool is the same as the Mini-system grooving tool from Enco but with carbide instead of the HSS inserts.

I really love the 60 threading insert.

Look for it on sale in the Hot Deals flyer and use the free shipping code. The people at Warner are good to deal with but thought I'd mention the alternative supplier.

http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=7908821&PMAKA=422-2880

Ken

 

[hssmike]

Ken,
Thanks for the support!! But our inserts (Warner) are the High Speed Steel ones - Enco has the carbide.
By the way, Enco inserts will fit our holder.


Thanks
Mike Warner
Arthur R Warner Co.

 

[abby]

Just a tip , when making HSS parting off tools I use a thin metal cutting disc in my angle grinder to make 2 cuts , this allows 90% of the surplus material to be removed in one piece in a couple of minutes, with practice it is possible to cut the relief angles too ,then just finish to size on the bench grinder

 

[Davyboy]

As mentioned by Abby, I've use the diamond coated disks from Harbor Freight ( Item 31501 ) to shape the tip of a groove tool. The disks are 13/16" dia, with 1/8" arbor, 5 pieces to a pack. The edge will cut off a 1/4" HSS tool bit real quick, without a lot of heat, and the diamond git goes across the face, to help shape the tool to finished size.
The round diamond bits, say .090 dia X 1/8" long, can also grind a cool chip breaker in the top of a lathe tool. Both of these diamond tools will work on carbide too.

DB

 

[bentprop]

Fwiw,broken hacksaw blades make excellent grooving tools up to the thickness of the blade.
With a short overhang they can even widen a slot,but that's easier with a more solid tool.

 

[websterz]

I part off a lot of 4140 using 5/16" HSS tools I form on my surface grinder. The best advice I can offer is to build a rear toolpost for the parting tool, and to run the tool upside down. Two big advantages, gravity helps keep the chips out of the cut, and the tool pressure is up and away from the part. If you do get a bit heavyhanded and snag the tool it pushes up and away from the work. I have not broken a parting tool since I went to the back tool post, and I tend to really push it. My tools are ground to .050" with no top rake. After I reach the proper width on the surface grinder I go to the bench and add a little relief to both sides of the tool for chip clearance. I can usually part off 30 or so pieces of 5/8" 4140 round before I have to dress the tool with a small diamond stone. I keep the tool cool with a homemade drip coolant system.