MadModder
Gallery, Projects and General => The Design Shop => Topic started by: chipenter on August 15, 2017, 09:07:42 AM
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I bought a set of ten tc engraving cutters from China , and have broken the tips from five so far , I made a simple jig to sharpen and put a relife angle on them , 1/2" Whit tread as it is turned in it puts the relife on , and any cutting angle is easely set , these are 20 degrees I hope these will last longer .
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A very neat idea using a coarse thread to create the relief - I must remember that one :thumbup:
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I'm looking over my copy of the Norman Tinker drawings and would be delighted to see more of it.
Perhaps you could oblige?
Thank You
Norm
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Do not try to use these cutters as is from China they are far too sharp
You need to take a single swipe with a diamond slip angled back a couple of degrees and sideways a couple so you have less of a point, more the flat you get with your 12 degree attachment
TBH I still prefer HSS for fine work, far more forgiving
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I was reliving the tip John but anything more than 0.2mm cut on brass and the tip went , 20 degrees gives a cleaner cut and the tip is still sharp , I will expriment further but still calling it a sucess .
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I am pleased to say the sharpend cutters work without breaking , sharpend the rest potoes show the relief ,
Norm I took some photoes of the Tinker its mounted on a Victorian Britannia lathe slide , no dials in those days perhaps thats were the term a smidge and a Nats wisker pluss outher parts come from .
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I was premature in saying no breakages tried cutting some CZ108 brass today , my mini mill did not like that at all and what it did cut looked rough antill the cutter broke .
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Norm I took some photoes of the Tinker its mounted on a Victorian Britannia lathe slide , no dials in those days perhaps thats were the term a smidge and a Nats wisker pluss outher parts come from .
I must say 'thank you' for an interesting resume. I understand it fully.
I also recall the old battle between the Quorn Owners and those with a couple of brackets- laughingly called a Tinker.
Cheers
Norm
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CZ108 is the problem and probably not your mini mill - CZ121 or CZ120 engrave much better.
I made a door plate out of CZ108 (because it's what I had handy) but engraved it with a 2 flute slot drill rather than an engraving cutter. I think you need positive rake (rather than the zero rake of your cutters), lots of clearance and lubricant to get away with it.
Phil.
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I modified the holder today as it put to mutch relife on , the cut was 1.2mm wide and cut the tops of the letters that should have stood proud , bored out the threads and fitted a plain collet holder , the relife is obtained by a flat on the leading edge and grinding the rest off , I still have to put some on indexing to get the required angle , the flat can be seen in the photo .
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I agree - it's a much easier way to grind engraving tools.
There's a useful diagram showing suitable clearance angles for different materials here: http://www.pilotltd.net/engraving.htm (http://www.pilotltd.net/engraving.htm)
Phil.
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Hi Phil
Just caught up with this very interesting post. Like all your detailed drawings and text.
Great info. Cheers David
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Hi Phil
Just caught up with this very interesting post. Like all your detailed drawings and text.
Great info. Cheers David
Hi David,
The only credit due to me is in finding the link!
Cheers.
Phil.