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    Default tool sharpening

    Does anyone have a mill sharpening machine or do mill bit sharpening? I have toyed with the idea of getting a machine if I could get enough business to pay for it and make a little money on the side but they're expensive and I've no experience in sharpening milling bits. I'm thinking I may be biting off more than I can chew. Money is tight so that's another issue. I would like to have some feedback from more experienced people. thanks

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    The way you sharpen endmills is to grind off the dull end, and re-point. Treat it like a break-off "box" knife.
    Reason: when your done the the endmill is still the same size, and still has the original geometry for cutting.

    Most of the time you don't use the endmill's full flute length when cutting. Usually you only need less than half of it's diameter when you are in the cut.

    You can re-point with a off hand "post" grinder.

    Regards,
    Stan-

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    If you want them to kick ass, "Mountain Top Sharpening" is your place. Forum member "jamesu229" should be able to get you the address.

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    If you bothered to do a search, and also check in the abrasive machining forum, this has been covered ad nauseum. Including just a few weeks ago on the AM forum.

    No direct comparison of a "machine" (purpose cnc set up?) but tons of stuff on manual machines, accessories, pros/cons, and business possibilities, if any.

    smt

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    Default end mill sharpening

    Quote Originally Posted by WDG View Post
    Does anyone have a mill sharpening machine or do mill bit sharpening? I have toyed with the idea of getting a machine if I could get enough business to pay for it and make a little money on the side but they're expensive and I've no experience in sharpening milling bits. I'm thinking I may be biting off more than I can chew. Money is tight so that's another issue. I would like to have some feedback from more experienced people. thanks
    .
    it has been my experience if you want to sharpen end mills it requires considerable time to get setup for particular size end mills to get primary and secondary clearance just right.
    .
    i believe many who do it professionally use cnc grinders with software setup to make it easy to setup different sizes much much faster like 10x or more faster. these machines i believe are very expensive easily over $10,000 maybe even $100,000
    .
    you might be able to buy old used manual machines for sharpening end mills. we have manual machines for rush jobs but they rarely get used.

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    There are good machines to buy such as Darex. They are expensive and for shops who do regrind their end mills a lot the shop may feel they should buy one. I have never seen a shop fully utilize one yet but hey I do not get around a whole lot. Neither have I heard of any shop fully working one they bought leading to most saying it was sort of a waste in investment. Perhaps it paid for itself.

    If someone has a gathering criteria they will often send them out to be done and pay. I know a guy who started out his own place doing it and back then his competition was very little. It could be something good to learn and also how to sharpen drills because many people do not know how to do that right.

    CNC grinders are pretty cool and you can buy them and select different settings to do different sizes. Even a drill press could make someone money if the person can find work and customers.

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    What's a mill bit?

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    Quote Originally Posted by Mtndew View Post
    What's a mill bit?

    Made by Rong Fu.... Turn 'em on, they let you mill a bit. Then they shake themselves to death.

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    Quote Originally Posted by DMF_TomB View Post
    .
    it has been my experience if you want to sharpen end mills it requires considerable time to get setup for particular size end mills to get primary and secondary clearance just right.
    .
    i believe many who do it professionally use cnc grinders with software setup to make it easy to setup different sizes much much faster like 10x or more faster. these machines i believe are very expensive easily over $10,000 maybe even $100,000
    Tom, About $500K for a new CNC grinder. Here's where we had our SME tour last nite. Awesome place. Equipment at Our Facilities
    JR

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    At least you would need a derex end mill grinder, air compressor, and would be nice to have a mill to test your grind on. Lots of videos on youtube. At school we have a derex. I have gotten pretty fast at them and they are sharp. Teach lets me bring in my own end mills to grind.

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    Quote Originally Posted by Metalcutter View Post
    The way you sharpen endmills is to grind off the dull end, and re-point. Treat it like a break-off "box" knife.
    Reason: when your done the the endmill is still the same size, and still has the original geometry for cutting.

    Most of the time you don't use the endmill's full flute length when cutting. Usually you only need less than half of it's diameter when you are in the cut.
    thats one approach and would work...but imo the proper way, proper in the sense that you you'll get a lot more sharpenings out of it and its less work, is to grind the perhiphery and you end up with a sharp cutter all over. Its also way, way...way less material to remove and T&CG isn't exactly a high removal rate op. of course you need to be set up for grinding the helix, so for many the point is moot.

    The dimensional change doesn't matter, you're taking a few thou off the cutter. if you are manual milling you're not suppose to rely on the mill diameter, ie measure before finish cut, and if cnc you punch in the new ground diameter
    Last edited by Mcgyver; 02-21-2015 at 08:09 AM.

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    Quote Originally Posted by Mcgyver View Post
    ...but imo the proper way, proper in the sense that you you'll get a lot more sharpenings out of it and its less work, is to grind the perhiphery and you end up with a sharp cutter all over...
    I sure agree with what you posted but why isn't the end of the cutter addressed. Is the assumption that the tips are only slightly worn and the peripheral grind removes that wear ?

    Thanks

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    The corner is likely going to see the most wear, so you could argue a bit off the bottom and a bit off the sides might be most efficient in getting to sharp with minimal material removal. Doing the end in this context means a few thou, its not heavy re gouging and reforming the end geometry like you'd have to do if you cut off the bottom 1/4 or 1/2" inch.

    When you do then helix, you are supposed to do the end as well if you're doing it as service for someone. For myself, I mostly skip the ends if it looks good after doing the pheriphery; after all the bottom is only used when plunging....not something I'm doing on a manual mill. Keep in mind the bottom of an endmill also isn't supposted to flat, the bottoms angle in a few degrees to the centre.....so on an endmill that hasn't beem plunged straight down, tuning up the periphery should be good as the bottom doesn't see much action. On my cnc, where there is lots of plunging, I'm using insert type chippers.

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    Maybe a good starting point.
    At the small volume low end there are resharps on manual stuff to be had for sure.
    You will kill the guys with fancy cnc grinders and that would be me as one. I just can not play here.
    Manual and low dollar grinders will always setup, run faster and be cheaper on small volumes. No doubt in my mine as I've spent time in the trenches with both..

    You don't have a few $500,000 grinders with $20K+ per year in maintenance that needs to make big bucks to stay alive.
    On this end you can setup and run small batches or weird stuff with little costs.

    The problem occurs when trying to turn the comer in having employes and not turning the handles yourself.
    The jump from a machine operator to the next step up.

    There is room on this end for anyone that can service his customer.
    Get these points hard, they are the big key ......Service and sales work.
    Make happy customers and the much harder part,...... walk away when you find that you can't make them happy.
    They will go elsewhere and at the least you did not leave them in a shithole they did not want.
    Bob

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    Quote Originally Posted by JRIowa View Post
    Tom, About $500K for a new CNC grinder. Here's where we had our SME tour last nite. Awesome place. Equipment at Our Facilities
    JR
    .
    from what i hear even though cnc grinder is $500K they are so much faster it has put out of business many
    manual sharpening places especially if cnc grinder has software where you enter starting cutter size and it
    automatically does setup calculations for you in seconds
    ......... sort of like making nuts and bolts on a manual lathe. nobody could compete against cnc machines

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    I guess I should be politically correct and have said "end mill", but I'm about as sharp as my "mill bits". I really wanted the feedback from this forum as I like to hear from people who I can relate too. All of the feedback is appreciated and I think I will try the "Mountain Top Sharpening" mentioned above. I only have, at this point, about a half dozen messed up end mills so getting into the sharpening business doesn't sound like what I need to try. I don't know if anyone has a preference as to where to buy end mills from but so far "Victor Machinery Exchange" seems to be pretty cheap, another reason not to try to get into the sharpening business. I would like to hear from anyone who knows where a better deal can be found on end mills. Always trying to save a buck. The deals on EBay worry me as you can't tell from the pictures which ones are good and which ones need sharpening.

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    I'm not sure I'd agree with everything I've read on this thread.

    I have a Darex E-90 and I can see that it would be difficult for a shop to keep one busy all the time. If you have a bunch of cutters to do they're quite fast, and if there's no funky geometry involved you just start at the biggest or smallest and just work through the pile. I was doing some that weren't mine a while back and they were giving me grief, but I can't for the life of me recall what the issue was. Anyway, normally it flows quite well. Whether there's any money in it as a business I wouldn't know, but if wouldn't think so.

    When sharpening, you normally sharpen both the sides and ends if the cutter is used "typically" for various operations in a regular job-shop environment. The corners of the end mill typically take the most beating, and I try to limit the majority if the sharpening to the ends if possible. Cutters will definitely cut undersize after sharpening the sides, indeed that can cause issues if I forget the cutter is undersize.

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    Quote Originally Posted by WDG View Post
    Does anyone have a mill sharpening machine or do mill bit sharpening? I have toyed with the idea of getting a machine if I could get enough business to pay for it and make a little money on the side but they're expensive and I've no experience in sharpening milling bits. I'm thinking I may be biting off more than I can chew. Money is tight so that's another issue. I would like to have some feedback from more experienced people. thanks
    I have an old Darex, its not the fanciest but does the job, Ive had it over 15 years, it was 1600 on sale then, I think they are about 3600 now for the same model, I use it quite a bit at times. I do some woodwork on a Tormach and that dulls carbide rather quickly. I also cut off the ends and regrind them as well. I built some machines for the dairy industry from 304 stainless, and bought it for those jobs. It does sit idle a lot but its already paid for and handy when I need it.
    I have seen them on ebay at times.


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