'ere, mate, this is just wot you need:
(cone-shaped drill, cone-shaped plug cutter, Japanese, for massive amounts of money.)
Have you tried grinding the outer circumference of a Forstner bit to make it smaller? Might work, though I'd try it on a cheap one first, mind.
Thomas Prufer
Unfortunately that just gives the home page on my browser and my German ain't up to much. But it sounds just what I need. Like all tools I don't mind paying if it does exactly what I want.
I did think of that but don't have the correct machinery to do it here.
I see that now -- I'd *told* it give me just the frame...
Search for "717255", alternatively "Japanisches Astloch-Reparaturset" -- beware, 128 Euros, unshipped!
But as tight a fit as you can pound it, and no need to drill at right angles to the surface.
I'd just offer it up to a bench grinder, and take a bit off the circumference by eye. (I had some Forstner bits where some genius had sharpened them with a scraper on the inside, after drilling them blue. Gently going round them on a bench grinder took off the bit that had been flared by the scraper, and restored them to some semblance of usefulness.)
Thomas Prufer
I would say almost imposible. I have a 'set' like you mention & use the plug cutters in a drill press - the instructions specifically mention using one.
No problem cutting the plug in a press - but having to drill the hole it goes into like that limits the uses somewhat.
Which is why some kind of jig to make a hole square to the surface is a good idea.
Try a drill press then a freehand hole and compare.
The problem is always at the very top of the hole if using a normal drill
- splintering etc. Which I can get round by using a forstner type. If only I could get ones of the correct diameter - or other types that give as clean a start. In my case it's got nothing to do with hand held drilling.
Ah. The cutter set that I have has a small pilot drill but the main part is more akin to a countersink bit but with sharp flutes. It doesn't tear out at all.
Indeed - I have some of the same. But haven't yet had a play with them to see if they work - they're actually combination bits rather than part of a plug set so may not be the correct diameter. Might as well just have a punt and order the set from Axminster.
I also have one of these :-)
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