Grinding your own lathe cutters

[duncan webster 1Participant @duncanwebster1]

Back in 1983 Ian Bradley described a very similar tool grinding jig in ME, the 'Target' Tool Grinding Jig. I've got copy of the article, if anyone is interested send me a PM

[Michael GilliganParticipant @michaelgilligan61133]

As a thank you to Duncan, and for the convenience of anyone wanting to build Bradley's version of the 'Target' jig

I have extracted the drawings **LINK**

https://www.model-engineer.co.uk/albums/member_album.asp?a=51365

MichaelG.

[duncan webster 1Participant @duncanwebster1]

If anyone is thinking of making one of these then using a square hole sleeve might be a good start **LINK** The company website says that Davall Gears are the UK agent. Quiet waht the minimum order charge will come to is anyone's guess, might be a case for interested parties to get together and buy a few

Having looked again at the drawings, if I make one I won't machine the angle on the main housing, if you do then using the protractor gets a bit awkward if the base is at an odd angle to the wheel. Tip the grinding machine rest instead seems better

[Ron LadenParticipant @ronladen17547]

Posted by ChrisB on 27/08/2019 15:05:20:

The radius you create is at the tip not the cutting edges. When you hone you create a rounded nose on the tip and sharpen the edges.

Look at this video, it's explaining the process in detail:

Dont know if any of you have watched the videos but video 2 concerns grinding a HSS fly cutting tool, which he then uses on aluminium with a speed of 1500 rpm.. I was amazed as I have been fly cutting at much slower speeds than that. So I had to give it a try and it works just fine leaving a really nice finish.

Any thoughts guys, I have been fly cutting alu at around 500-600 rpm was I wrong..?

[JasonBModerator @jasonb]

A lot will depend on the diameter of the arc the flycutter is swinging at much the same as the diameter of work in the lathe affects revs. I don't run my big flycutter as fast as the smaller ones.

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 04/09/2019 10:49:57:

A lot will depend on the diameter of the arc the flycutter is swinging at much the same as the diameter of work in the lathe affects revs. I don't run my big flycutter as fast as the smaller ones.

I just checked and the cutter is at 60mm diameter.

[Douglas JohnstonParticipant @douglasjohnston98463]

I recently made a flycutter from an old damaged 6" faceplate which I had in my scrap box. I made a holder for my favourite TCGT inserts with the cutting edge at a radius of about 3" and then carefully balanced the whole thing. The result was a flycutter which could be run at around 500rpm and which gives superb surface finish. It also has the advantage that it will cover most parts without the cutting edge making any trailing marks.

Doug

[VicParticipant @vic]

I use a belt sander for tool sharpening and I can get a virtually polished surface on tools using a 240+ grit belt. I must try this next time on my Tangential Tool so see if it makes a noticeable difference in surface finish.

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