Grinding and sharpening coated end mills

[derek hall 1Participant @derekhall1]

Hi everyone

Just a general question, now I have almost completed my Quorn grinder as it has taken me so to build it!, I have noticed that not only normal uncoated end and slot mills are available but coated versions of end and slot mills.

My question is therefore while the Quorn should be able to deal with the normal (traditional?) End and slot mill cutters, what about the coated variety such as those on the ArcEurotrade web site I.e. TiAIN and TiN cutters?

If so would the same grinding wheel for standard HSS be suitable? Or are these coated variety whilst supposedly longer life, be regarded as non resharpable and therefore disposable after getting blunt?

The current attractive 15% off sale in ArcEurotrade has a lot to do with my question!

All the best

Derek

[derek hall 1Participant @derekhall1]

[Howard LewisParticipant @howardlewis46836]

The TiN coating is there to reduce friction, as I understand it.

Have not been aware of any major problems on the TiN coated drills that have been sharpened on my Worden with pink grinding wheel. So Milling cutters wqould not seem to be a problem

HTH

Howard

[BazParticipant @baz89810]

Congratulations on finishing a Quorn, the coated cutters when sharpened and the coating ground off just become normal uncoated cutters, industry may well throw them away because their processes need the coating intact but for our needs it doesn’t matter at all. Get yourself a small diamond or CBN wheel for the Quorn and you will be able to get them sharpened back to as new sharpness.

[Mark RandParticipant @markrand96270]

At work, coated carbide endmills were resharpend and recoated, but they were spending more on endmills and inserts per month than most of us have spent for our entire workshops!

[derek hall 1Participant @derekhall1]

Wow, thanks for all the quick replies !

What a great forum this is !

Thanks

Derek

[alan ord 2Participant @alanord2]

I was Operations Manager of B&D machine shop in Spennymoor Co Durham and we used to produce millions of gears and splined shafts for power tools. We used to hob the gear profile using coated hobs and regrind the hobbs in house. The coating is, as mentioned by Howard, to reduce friction, therefore by regrinding the the cutting edge does not remove the coating from the rest of the hob flanks. We used to hob gears and shafts hard up to 65 Rc which eliminates distortion that is induced by post heat treatment as is customary. This has a dramatic affect of reducing gear noise. As an interesting story, I visited A German machining company called Hertzog and when I told the owner we were hobbing at 65 Rc he would not believe me. When I got back to the UK he called me and asked if he could visit the factory. He did and we showed him the process including prior hobbing component hardness checks. He was still sceptical and asked if he could take some components he watched being hobbed and components prior to hobbing. we also allowed him to photograph the process. He was very complimentary of how we were machining the parts.

Alan.

[old martParticipant @oldmart]

If your regrinding is limited to trimming the ends, the cutters will work well enough for hobby use without recoating them.If you regrind the OD and loose the coating and some diameter, they would still work, especially for aluminium.

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