Doing Counterbores

JPG · Post by **JPG** » Thu Aug 30, 2012 4:45 pm

foxtrapper wrote:Seems any time I use a standard counterbore bit like the OP showed, I'll get lots of chatter and a triangular shaped hole or bowl. Someday I'll study that triangular bit.

I get my best results with a remarkably crude tool. These:

Got them many years ago. Nothing more than a flat piece of steel with the end rounded up so it fits in my drll. They don't chatter and produce a superb hole.

In MDF with only a 1/4" sheet to countersink? I doubt it! I had these several decades ago and gave up on them. OK for course work.

JMHO!;)

dusty · Post by **dusty** » Thu Aug 30, 2012 6:40 pm

foxtrapper wrote:Seems any time I use a standard counterbore bit like the OP showed, I'll get lots of chatter and a triangular shaped hole or bowl. Someday I'll study that triangular bit.

I get my best results with a remarkably crude tool. These:

Got them many years ago. Nothing more than a flat piece of steel with the end rounded up so it fits in my drll. They don't chatter and produce a superb hole.

I have used these very successfully but only for applications where I was predrilling for a counter sunk screw. I suppose they could work for applications like drilling the counter sunk holes for the ZCI to mount to the saw table but I have not tried that. I will when I test the others that I just ordered.

JPG · Post by **JPG** » Thu Aug 30, 2012 10:34 pm

dusty wrote:I have used these very successfully but only for applications where I was predrilling for a counter sunk screw. I suppose they could work for applications like drilling the counter sunk holes for the ZCI to mount to the saw table but I have not tried that. I will when I test the others that I just ordered.

They will need a small pilot hole, and with thin material, you may need to back it up with the pilot hole in BOTH the workpiece and the backup.

easterngray · Post by **easterngray** » Fri Aug 31, 2012 12:15 pm

I regularly countersink oak and cedar at work. The best method is to install a countersink sized to the bit you are using and countersink as you are drilling. In my opinion W.L. Fuller makes the best countersinks. They have been around for a LONG time and their tools are great. Here's a link:
http://www.jamestowndistributors.com/userportal/search.do?freeText=fuller%20countersink&page=GRID&engine=adwords!6456&keyword=fuller_countersink_set

and here's a video::

http://www.youtube.com/watch?v=5VMBMFF9sHQ

dusty · Post by **dusty** » Fri Aug 31, 2012 1:19 pm

easterngray wrote:I regularly countersink oak, spruce, cedar and fiberglass at work. The best method is to install a countersink sized to the bit you are using and countersink as you are drilling. In my opinion W.L. Fuller makes the best countersinks. They have been around for a LONG time and their tools are great. Here's a link:
http://www.jamestowndistributors.com/userportal/search.do?freeText=fuller%20countersink&page=GRID&engine=adwords!6456&keyword=fuller_countersink_set

and here's a video::

http://www.youtube.com/watch?v=5VMBMFF9sHQ

Thanks for the prod. I have one of these and I don't know where it came from. I never use it.

[ATTACH]18335[/ATTACH]

PS: I only have two and they are both the same size (#3). Don't know what I would use them on but I'll try to remember I have them just in case.

terrydowning · Post by **terrydowning** » Fri Aug 31, 2012 2:37 pm

Starter bit typically used in metal working used for making 60 degree holds for dead and live centers on a metal lathe. Also great for starting out drilling. I use these in my pen making to start the drilling process. They don't walk or slide at all, they just start the hole so a larger bit can come along after it.

JPG · Post by **JPG** » Fri Aug 31, 2012 3:11 pm

#3 = 1/4" od with 7/64" pilot.
http://www1.mscdirect.com/cgi/NNPDFF?PMPAGE=193&PMITEM=88236112&PMCTLG=00

Give it time to load(2x), and scroll down near the bottom of the page.

reible · Post by **reible** » Fri Aug 31, 2012 3:35 pm

Hi,

Here are the ones I got from Grizzle a couple of years back when I discovered I no longer seem to have my original set. If I recall the 1 - 4 were a package deal and the 5 and 6 were separate. I've included a 1/8", 1/4" and 1/2" drill bit so you can visualize the sizes better.

[ATTACH]18336[/ATTACH]

Well worth having in a wood shop and really needed if you do metal work.

I believe I have posted some pictures and shown uses for these a while back, however I don't recall the subject(s).

Ed

JPG · Post by **JPG** » Fri Aug 31, 2012 3:42 pm

reible wrote:Hi,

Here are the ones I got from Grizzle a couple of years back when I discovered I no longer seem to have my original set. If I recall the 1 - 4 were a package deal and the 5 and 6 were separate. I've included a 1/8", 1/4" and 1/2" drill bit so you can visualize the sizes better.

[ATTACH]18336[/ATTACH]

Well worth having in a wood shop and really needed if you do metal work.

I believe I have posted some pictures and shown uses for these a while back, however I don't recall the subject(s).

Ed

More gooder than a chart!;)

reible · Post by **reible** » Fri Aug 31, 2012 3:47 pm

If you are interested this will get you started shopping at Grizzly for these bits:

http://www.grizzly.com/catalog/2012/Main/634

Ed