One advantage of the ones with the interchangeable pilots is that, once one
has removed the pilot, the cutting edges are easily accessible and could be
sharpened, with care, on a bench grinder. The reason I got them was that I
didn't just want to use them for cap-head screws, so I can use different pilot
and counterbores size ratios, even make new pilots if I want.
To be honest, unless you are doing serious production or difficult materials,
I don't think you'll need carbide for a counterbore. If you do, you'll already
be using carbide drills and you won't be swimming in Chronos and Warco's pools
Just a comment but I find the "standard" counterbores too big on the
counterbore and too big on the spigot!
For model (and tooling) work I personally feel that standard
counterbore diameters look ugly.
Accordingly I tend to use standard milling cutters for the
counterbores, metric or imperial to give a nice look to the job.
However I must admit to have been tempted, more than once, by the J&L
set with interchangeable pilots, (as mentioned by Mark).
On Tue, 25 May 2010 23:30:47 +0100, Richard Edwards
Found that on one last Saturday. Had to machine off nearly a whole thou from a
pilot to make it fit a 3/8" reamed hole.
10 thou would be far easier. Ended up centring it in the four jaw, spinning it
up and stoning it off. Took far longer than it should have :-(
Not in sets as far as I know, but have a look at page 133 of the current
catalogue for Imperial ones - I don' think they do metric. Nice thing about
them is that you can make a pilot for any size hole you like.
On 26 May, 18:47, "Norman Billingham" <norman.at.tumulus.org.uk>
Apologies for reviving an old thread, I've been on the lookout for a
set of metric counterbores with separate pilots since they were
mentioned on this thread, so in case anybody else is interested I've
finally found some here: http://amadeal.co.uk/acatalog/HSS_Flat_Countersinks_-_Counterbores.html
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.