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Re: Making a multiprofile Drill bit |
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| message from Capitol on 9 May 2004 |
Just regrind a spade bit with a bench grinder. This can be done adequately
by eye. Keep the material cool by dipping frequently in water to stop it
softening and make sure that the edge cutting angles are not too steep.
Regards
Capitol
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| N. Thornton replied to Capitol on 10 May 2004 |
I need a 4.5" bit 3.5mm and 6mm wide. I've never seen a 6mm spade bit
with a shaft thin enough to be ground down to 3.5mm, nor one with a
flat section at least 2.5" long. Thems is the problems.
Regards, NT
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| Tony Williams replied to N. Thornton on 11 May 2004 |
Would it be easier with two drillbits?
No1 is a standard 6mm drillbit, pointy end ground
for wood, and with a depth stop. That gets you the
main hole, swarf pumped out, and ready as the guide
hole for drillbit No2.
No2 is a length of 6mm bar, drilled at the front with
a 3.5mm drillbit brazed in. At the back end of the
6mm bar have a combined countersinker (or recessor)
and end-end depth stop.
No2 *might* be made from a cheap spade bit, right
size for the countersink, but running backwards, with
the 3.5mm bit brazed into the end of the drive shaft.
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| Capitol replied to N. Thornton on 10 May 2004 |
Interestingly enough, the type of countersinking drill bit ( spade version)
that you are looking for was common about 40 years ago. They were very
popular for boatbuilding in wood. I still have a couple of these which have
survived, but I've only seen very low grade bent steel versions in recent
years. As an afterthought, if you want to construct a spade type drill from
a 6mm rod, then you may well find that a sacrificial 6mm allen key is a good
starting point. This will probably be hard enough for 40 holes in softwood
if you don't overheat the steel.
Hope this helps
Regards
Capitol
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| Capitol replied to N. Thornton on 10 May 2004 |
news:<c7m8oh$m35$1@news5.svr.pol.co.uk>...
I've just checked, the last lot of spade bits I bought in the £ shop have a
7mm shaft. Get grinding!!
LOL
Regards
Capitol
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| Capitol replied to Capitol on 10 May 2004 |
Bloody optimist!
Capitol
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Archived message: Re: Making a multiprofile Drill bit (UK DIY Home Decoration)
