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Post by niels on Mar 29, 2020 19:18:09 GMT
Another source of square carbide
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waggy
Statesman
Posts: 744
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Post by waggy on Mar 31, 2020 8:39:16 GMT
Good morning all,
The square carbide blank arrived yesterday. It took nearly two hours to grind the end to profile using the jig provided by eccentric engineering. I found that the green grit wheel got a polished surface after a few minutes work and just about stopped cutting, a quick touch with the diamond dresser soon remedied matters though. I suppose the hard metal started to polish the grit?
The tool cuts really well, my test piece was a 1” cast iron bar, nice easy cut at slow speed and a lovely polish cut at top speed (@1250 rpm). I then followed the same procedure with HSS, the slow speed cut was ok but the high speed just took the point off the tool, as expected.
Compared to a HSS blank with sharp corners the carbide is radiused along its edges. Run your finger along HSS and you can feel the sharpness, not so with the carbide. To get a sharp point on the cutting face you have to dress the two sides of the face or there is a small radius on the cutting point. I did this after the first test and as soon as the tool touched the job the sharp corner chipped off, as has been suggested previously! The radius is there for a purpose!
Anyway, the upshot is that I’m happy with using it, especially on cast iron, not tried it with other metals but I dare say all will be well.
Thanks to all who’ve replied, I hope my test can be of use to others who may be wondering.
Stay safe,
Waggy.
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Post by Roger on Mar 31, 2020 10:23:52 GMT
It would be interesting to know if the Carbide blank is made of the same grade as used on milling cutters. Those are usually razor sharp and don't chip that easily. I think you'll get great results with it on other materials, although a sharp point when looking in plan view isn't ideal for getting a really smooth finish. I'd be inclined to put a small radius on that by hand.
I don't think you need a high speed for finishing. In my opinion the only benefit is that it's completed quicker, I very much doubt that the finish is any better than doing it more slowly.
I've had notification of the dispatch of mine, so hopefully it will be here in a week or so.
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Post by jcoghlan on Apr 6, 2020 21:52:42 GMT
Hi I use a firm called Cutwel they sell tool holders that take carbide inserts. They are very helpful. Everything is sent next day delivery and they have an amazing range. John Coghlan. Chairman. Handforth model engineering society
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Post by Roger on Apr 6, 2020 22:07:30 GMT
Hi I use a firm called Cutwel they sell tool holders that take carbide inserts. They are very helpful. Everything is sent next day delivery and they have an amazing range. John Coghlan. Chairman. Handforth model engineering society I've used Cutwel and they're certainly good. However, you can buy almost anything that they sell cheaper on eBay, so I don't use them any more unless it's for an odd threading insert that I can't find.
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