Cogsdill face burnishing tools. Are they worth the price?

Apparently I've been across the pond too long and missed these when they came out a few years ago. I'm setting up to run some S7 and calls for a ground finish but if the tool will do what Cogsdill is claiming then I may be able to sway the customer away from grinding.

Yeah, I can call Cogsdill and ask them all the specs but would prefer to hear it form a customer using one in the real world applications.

Diamond Burnish Face Mill Tools by Cogsdill

g-coder05 said:

Apparently I've been across the pond too long and missed these when they came out a few years ago. I'm setting up to run some S7 and calls for a ground finish but if the tool will do what Cogsdill is claiming then I may be able to sway the customer away from grinding.

Yeah, I can call Cogsdill and ask them all the specs but would prefer to hear it form a customer using one in the real world applications.

Diamond Burnish Face Mill Tools by Cogsdill

Click to expand...

Haven't tried these yet myself either.

S7 tool steel ?

I'm guessing the cogsdill burnisher will work harden the surface layer of the material. The diamond tools / pins are spring loaded.

Purely for surface finish but won't make a surface as flat theoretically as a 1/2 decent surface grinder. [But maybe flatness is not called out here / in your case.].

Burnishing / work hardening the surface can increase corrosion resistance but may not be what the customer wants?

@gcoder I'm sure you know all this anyway... So it's kinda like suck it and see sort of thing.

We have just completed a job that required(apparently) burnishing to 0.2RA. In a bore, 140ish diameter.
Cogsdil wanted £1780 for a universal burnishing tool.
The finish we finish we achieved was 0.3, customer was happy with that.
We used a CNMG wiper tip and give the bore a bit of an emery.

For facing finishes we have a lapping machine which will get a .1RA finish.
Does anybody Lap in your area?

Purely for surface finish but won't make a surface as flat theoretically as a 1/2 decent surface grinder. [But maybe flatness is not called out here / in your case.].

Click to expand...

Good call, In all the hype of the finish I totally missed the flatness call out. These are forging dies for hooks and clevis's so guess there's no easy way to get out of grinding.

Thanks for catching what could have been a nasty nono for me.....

I haven't used a burnish tool for facing, but have used an Elliot Burnishing Tool for bores.

I bought as it was a very tight, deep bore calling for a good finish. Its been awhile so kept the call outs vague, but +/-.0002, 4" deep and around 1.625 diameter to a shoulder are about the area...basically a small boring bar with sharp edge and little support. I played with boring test parts first with a win some lose some consistency that would not fly in production. I could easily hold +/-.0004, usually .0003 if I kept the feed up a bit, bit finish lacked.

Anyway, the burnishing tool promised to achieve twice the finish and reduce tolerance by 1/2...so my +/-.0004 became a +/-.0002 while giving a great finish and my customer loved that it was harder, although not a requirement.

I guess I could have sent out for honing or grinding...but something about keeping jobs in house is worthy of buying a $500 tool.