Hi All,
I'm looking at doing some adapter plates and I need to do some counterbored (or flat bottom/dowel) holes in aluminium/steel - yet to be
decided... anyway, I am trying to find something that fits into a power drill rather than a lathe or mill but struggling to come up with anything
yet...or if anything like that even exists?
Cheers
Depending how large you are looking for maybe you could get away with an end mill, if the work is securely fastened down. Alternatinely, ground a
drill to the shape you require....
[Edited on 9/11/15 by redturner]
Re sharpen the same size drill without the normal angle to give flat bottomed hole.
Thanks for the quick responses guys. I'd be looking at doing a couple from around M6 to M12 bolts so even with the allen key type bolts I'd
be looking up to around 20mm I guess? Unfortunately my drill only has a chuck that accepts up to 10mm shanks and struggling to find anything that
suits...
The aim was to do it myself rather than have a machine shop do everything (time and money etc)
this is hss, so should do ali, drill hole, then use this for counterbore
http://uk.rs-online.com/web/p/counterbores/5089266/
I'd get a drill ground, there are various other options,. end mill in a router, wood bits used carefully, forstner cutters, etc, but a step drill
is the easiest. As you have a 10mm chuck you'll require blacksmiths drills, they have a reduced shank for smaller chucks.
The issue maybe that a large drill reground will cost more than getting someone else with the correct kit to do the job,..
hth
Yeah I'm putting together a CAD model and using scale paper print outs to help validate my measurements. Only worry I have is going from CAD to finished part...Looks like I'll be taking the plunge with a machine shop and have faith in my own work haha
I've used these sort of things in a pillar drill.
http://uk.farnell.com/ruko/102411/counterbore-hss-m6/dp/282390?mckv=WUEAIbrX&CMP=KNC-GUK-FUK-GEN-SHOPPING-RUKO&categoryName=&CAGPSPN=pla&a
mp;gclid=CM2Y3-Oqg8kCFVOZGwod-oYJ0A&gross_price=true&ost=282390&categoryId=&CAWELAID=120173390000304974
[Edited on 9/11/15 by owelly]
You can fairly easily turn a standard HSS drill bit into an acceptable counterbore bit on a bench grinder.
You can either make the end completely flat (even easier if you start with a wood bit) and just use it to flatten the bottom of a hole drilled with a
standard bit, or grind a spigot of appropriate diameter in the middle, in which case you can just drill the clearance hole for the bolt, and then
drill the counterbore.
[Edited on 9/11/15 by MikeRJ]
Hmm a re-ground drill in anything other than a mill will end in chattery nightmares from hell at best - snatching and demolished workpiece and tool at worst.
quote:
Originally posted by gremlin1234
this is hss, so should do ali, drill hole, then use this for counterbore
http://uk.rs-online.com/web/p/counterbores/5089266/
I have used my method putting central 10mm plugs in bike cylinder heads. Just make sure it is clamped down tight and use a slow feed.....
quote:
Originally posted by coyoteboy
Hmm a re-ground drill in anything other than a mill will end in chattery nightmares from hell at best - snatching and demolished workpiece and tool at worst.
6 piece counterbore set on special offer here
Almost all of the time we use drill bits for holes to put bolts through or to tap to screw bilts into so it doesnt need to be as precise as for holding dowels, no idea if this s an issue for you.
quote:
Originally posted by Rosco86
quote:
Originally posted by gremlin1234
this is hss, so should do ali, drill hole, then use this for counterbore
http://uk.rs-online.com/web/p/counterbores/5089266/
nothing wrong with this method