Thread: Miebach Colt Drill Bitt

If Brett (FenceFurniture) hasn't chipped in by tomorrow, send him a pm.
Brett is the resident expert re Colt drill bits

Originally Posted by thumbsucker

Have they vanished if yes what’s a high quality replacement brad point metric bit.

Buy good HSS twist drills and re-grind them.

I will say at the outset that others have far more knowledge on Colt drills that I do.

From my limited understanding, the manufacture of these drills moved from Germany to France (whether under a different company name, I am not sure, but suspect so).

I have found a source for them, but whether they are the same as the "old" Colt drills, I do know know. That said, if these are made in Europe, they should be pretty decent.

See here: https://www.fine-tools.com/bohrspiral.html

I'd be more than happy to be corrected on the above - please bear in mind this is what I recall hearing at some point in the past.

I bought some Star-M brand drills from Japanese Tools Australia at the last Timber and Wood show, and find them absolutely great. I have never found any drill that cuts as cleanly. As to longevity, I have not had them long enough to form an opinion. They are available in sizes from 3mm up to 18mm (IIRC).

Are these the drills you brought mspil?

Those Japanese bits look interesting but they do not come in 16mm.

Fine Tools has a good range but again the 16mm is out of stock.

Originally Posted by thumbsucker

Those Japanese bits look interesting but they do not come in 16mm.

Fine Tools has a good range but again the 16mm is out of stock.

do you really need a 16 mm drill bit?

5/8" is an 1/8th of a mm less than 16 mm -- would you really notice the difference if the drilled hole were 15.875 mm rather than 16 mm?
Could you even measure the difference?

I am making post and rung chairs. Just for example the Veritas Tenon cutter cuts a 3/4” about (19.05) Tenon - Can be adjusted (which will be super dried) and then I need the hole to be smaller so 19mm hole would be good

From memory Jenny Alexander suggested a 0.25mm difference between Tenon and mortice.

For a 1/4” a 6mm would be a better fit.

In the past you could just find a 3/4” drill bit that was undersized and off you go. But with modern precision machining you need a workaround.

I've got Colt brand Brad Point & Forstner Bits from both France and Germany, Our Partners - Home - About Our Company - Colt
thanks to a very helpful forum member, Brett, already mentioned.
I've also purchased a set of W.L.Fuller made in the USA set which are equally as good, W.L. Fuller Inc. - Tools to cut woods, plastics, and metals.
though the exchange rate at present would be the killer for them.
Cheers, crowie

Originally Posted by thumbsucker

I am making post and rung chairs. Just for example the Veritas Tenon cutter cuts a 3/4” about (19.05) Tenon - Can be adjusted (which will be super dried) and then I need the hole to be smaller so 19mm hole would be good

From memory Jenny Alexander suggested a 0.25mm difference between Tenon and mortice.

For a 1/4” a 6mm would be a better fit.

In the past you could just find a 3/4” drill bit that was undersized and off you go. But with modern precision machining you need a workaround.

so are you after a 5/8" / 16 mm pair, or a 19 mm / 3/4" pair ?
And if 16 mm, would a 15 mm bit suffice? -- I know that 15 mm drills and tenon cutters are available, and suspect that in the US you can get 5/8" drills and tenon cutters

I needed a 19 for some reason 16 got into my head. 1 mm diffence is to much 0.25 is about the sweet spot. Then Tenon is super dry 2-3% the mortice is wet 15% their is a fair amount of compression in wood however when the Tenon goes into the mortice it sucks up water and expands however if to tight the Tenon can split the mortice as the Tenon increases its moisture levels.

Also it’s hard enough pushing an oversized Tenon into the mortice with a 0.25mm difference. 1mm would be impossible and that is with no glue.

Originally Posted by thumbsucker

I needed a 19 for some reason 16 got into my head.

Also it’s hard enough pushing an oversized Tenon into the mortice with a 0.25mm difference. 1mm would be impossible and that is with no glue.

I meant using both a 15 mm drill and 15 mm tenon cutter.

similar for 19 mm, would a 20 mm pairing work?
13/16" = 20.64 mm and is available from Lee Valley and Dictum carries 20 mm Fisch tenon cutters https://www.dictum.com/en/circle-cut...e-20-mm-707053

If you were using glue and dry wood then yes Tenon & mortice can be the same the size.

If you using greenwood then the Tenon needs to be a touch bigger. In imperial they would say a fat 3/4” Tenon.

I already have the Veritas Tenon cutters. They are good in that while they stipulate that a cutter is 3/4” the blade shifts so you can make a thin or a fat 3/4” Tenon.

So if I was an imperial user then I could use a standard 3/4” drill bit and just make a fat 3/4” Tenon. However I prefer to have a metric drill bit then adjust my Tenon to be a little fat metric.

I have made post and rung chairs before and I am planing to make some more soon. The last one I made had no glue and the joints are as solid today as they were three years ago and that’s with daily use.

Originally Posted by thumbsucker

I already have the Veritas Tenon cutters. They are good in that while they stipulate that a cutter is 3/4” the blade shifts so you can make a thin or a fat 3/4” Tenon.

I prefer to have a metric drill bit then adjust my Tenon to be a little fat metric.

if the Veritas tenon cutter adjusts enough to make a "fat" or "thin" 3/4" tenon, it will also adjust enough to make a "fat" or "thin" 19 mm tenon. The starting diameter of a 19 mm tenon is only 0.05 of a mm different to that of a 3/4" tenon.