Sharpening gear cutters

[Roger HulettParticipant @rogerhulett83124]

Does anyone know of a company that will sharpen a one off gear cutter. I have Googled this with no success as the people who advertise are industrial. I do not want to risk doing it myself. Any help will be appreciated.

[Roger HulettParticipant @rogerhulett83124]

[Nick HughesParticipant @nickhughes97026]

Hi Roger,

Try these guys:- **LINK**

Nick.

[Brian WoodParticipant @brianwood45127]

Hello Roger,

It is not difficult, sharpening is done exactly down the radius of each tooth to preserve the form relieved geometry. Correct indexing is important so that you take off the same amount on each tooth, it will then cut with the same load on each tooth.

If you really are not confident enough to do it, send me a PM and I'll give you my address, I have a slim diamond wheel that will get down into the gash to the root without risking a foul on the adjacent tooth..

Regards

Brian

[AjohnwParticipant @ajohnw51620]

I vaguely remember some one showing me that the teeth can be used for the indexing and as unintuitive as it might sound they all cut correctly even the last one.

It would be interesting if some one could confirm that.

John

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[BazyleParticipant @bazyle]

As Brian said ideally you don't index off the front face as you would for a milling cutter but use an independent index method.

John is probably thinking of the Clarkson (or equivalent) fixture that uses a very rigid framework to reference a point part way down the relief face (ie outside edge) of the cutter effectively picking up a point that is exactly the same radius for each tooth. Then given that the relief of each tooth is a consistent angle the front face can be trimmed to the exact same distance from that radius point and hence have the same tooth tip radius.

[AjohnwParticipant @ajohnw51620]

It was carbide tipped saw blades Bazyle, lots of teeth. I had one done and then asked just how they did it and was shown. A very long time ago. From memory the index was on a tooth that wasn't being sharpened and it all worked out – even on the last tooth. The grinding wheel was positioned to apply the cut at what ever angle is needed.

The technique is shown at the end of this video. There may be better ones about

**LINK**

John

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[Phil PParticipant @philp]

When I sharpen an involute cutter or a hob, I begin by grinding the backs of all the cutting teeth so they are all consistent by using the original front cutting face as a datum for the detent on the grinder.

Once a cutter has its teeth back ground, I then use the back of each tooth for the indexing detent on the cutter grinder to do the actual sharpening.

My dad taught me that trick years ago, and it works perfectly every time.

Phil

[John ReeseParticipant @johnreese12848]

Phil P's method is necessary on all form relieved milling cutters during the initial resharpening. It does not have to be repeated on subsequent resharpening.

It is also necessary to preserve the rake angle on the face of the tooth. The face of the tooth will be offset a certain amount from the center line of the cutter. That offset has to be maintained curing resharpening to preserve the rake angle.

[Martin ConnellyParticipant @martinconnelly55370]

I have seen cold saw blades that have been repeatedly sharpened using a blade in the gullet to index the rotation from tooth to tooth. After repeated sharpening like this the blade gradually goes out of round and becomes more egg shaped as the process multiplies any small error in the original blade. Original manufacturers of industrial blades (and now some third parties) use proper indexing fixtures to sharpen the teeth to keep the blades circular. Current cost for resharpening a Ø350mm blade is about £10.50 +vat. This is based on a batch size of 40, we use them on stainless steel so get through a lot. It is far cheaper though than regularly replacing them. Some have been sharpened so many times they are down to about Ø200mm. At this size they are only good for small stock.

Used in one of these **LINK**

Martin

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