Endmill regrinding

Ignoramus20088 fired this volley in news:-LKdnQlAtJugBpbTnZ2dnUVZ snipped-for-privacy@giganews.com:

YOW! It wouldn't take long to pay for a Darex at those prices!

I happen to like (really like) pristine-sharp milling cutters, and being able to touch one up on-the-fly (as it were) would be a big benefit.

LLoyd

There are some really nice toys out there. I presume the machine laser marks the new dimension on the end mill so you have the correct info for your cutter comp.

Sounds a tad expensive, I expect if you did regular commercial business with them the prices would be lower.

Ask them how much to regrind 1mm and .03125" carbide ball mills. LOL.

But would Darex really do that good of a job, compared to this CNC 8th wonder of the world?

And, additionally, how much time would I spend per end-mill with a Darex?

I am not trying to argue, I just want to try to consider this properly.

So, say, an angel comes from Heavens and brings me a Darex E-90.

How well will it really work for me, in real life?

I want to see how it works out, to buy used end mills at auctions, pay for sharpening, and sell on ebay. If it works out nicely, I will do that regularly. At auctions, carbide end mills usually sell below scrap prices, which are $15 per lb.

I bought 15 lbs of carbide end mills (with very minor wear) for $28 on ebay last week. Those were 1/2, 5/8, and 1" end mills.

What you have to watch out for with carbide are micro fractures.

Ignoramus20088 fired this volley in news:9cednROpdsiJTJbTnZ2dnUVZ snipped-for-privacy@giganews.com:

'Couldn't tell you, having not used one, but they come precious, even used, and high prices at re-sale usually mean they're well-accepted.

I have looked at the manuals and specs, and they spec-out as being able to do very precise re-grinding.

There's at least one on E-bay right now for under $2000, used.

LLoyd

Ignoramus20088 fired this volley in news:9cednRKpdshPTJbTnZ2dnUVZ snipped-for-privacy@giganews.com:

Keep in mind that "very minor wear" translates to "much higher cutting forces" and "lots of green-stone wear" to get back to "no wear at all".

At avg. $12.00 per endmill, you'll play hell getting back your $15/lb investment, Ig.

Re-sharpened used milling cutters aren't of much use unless they come with diameter specs from the sharpener.

LLoyd

Any difference in price between HSS and Carbide end mills? Thanks, DoN.

Lloyd, I basically doubt that regrinding on my own is the right thing to do. This is what I want to clarify. I could justify an end mill grinder IF I can make money buying used end mills and sharpening. But I doubt that in the final analysis, it wil be proven to be worthwhile.

I do not know, I have not asked. But there is a big difference in the selling price of end mills.

Ignoramus20088 fired this volley in news:49udnTWUSaa4fJbTnZ2dnUVZ snipped-for-privacy@giganews.com:

That's where we differ, I guess. I figure I've used up all the "good" in a brand new HSS cutter in about an hour of optimum cutting (and with my old BOSS-9 machine, the spindle doesn't run fast enough to be at "optimum" very often). That, for me, ends up being about one part for most of the machines I build. Even a _slightly_ less-than-perfect sharpness results in much higher machining forces and worse surface finish. Using the wrong surface speeds and tooth loads worsens the wear, and I can't help those two problems right now. So I wear bits rapidly.

So it would be very nice to spend 3-5 minutes on a Darex and snap that "worn out" bit back up to correct sharpness for the next part. I can do the diameter compensations in my tool setups. I keep looking for a Darex E-90 I can both afford and is in good enough condition and well-enough equipped with collets to warrant spending the money.

LLoyd

Yep, tool diameter compensation is not a problem for me either.

I still would like to know how much time DIY regrinding takes, and whether it is as good as a $7 apiece CNC job.

I looked one over once and was not exactly impressed with the rigidity of the unit. Oh, you can sharpen an end mill for sure. But will it be the equal of the CNC sharpened mill? I very much doubt it.

If you want to make money sharpening mills, you need that fancy CNC machine IMHO...

Jon

I thought along those lines.

Which makes sense, economically. Just 2 weeks ago, I participated in liquidation of an end mill regrinding shop equipped with old style stuff (KO Lee, Cinci etc).

Not sure what kind of machine my guy has, but he is half that price. I'm very happy with his work.

Remove 333 to reply. Randy

Where is your guy located?

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FWIW, I have a Darex spindle that I can mount to my tool and cutter grinder.

It's been a few years since I've sharpened any endmills with this set up. "Unfortunately", I keep scoring new ones at ridiculous low prices so I don't need to sharpen very often. :-)