Drilling Countersink Holes in 1/4" Hard Board

[JPG]

The shear cutting countersink bits will chatter if the workpiece is allowed to move.

The drilling of a hole significantly larger than the countersink bit at the bottom of the cutting edge will increase the possibility to chatter.

The shear cutting bits I previously used had a cylindrical projection at the end that allowed it to act as a guide in a pilot hole nearly the same diameter.

I would keep the pilot hole small when using the Lee Valley bits and enlarge the through hole after countersinking.

[Ed in Tampa]

I received my order from Lee Valley and these bits do work well but I do not believe they are any better than the others I have used previously. After using a few different bits, I have concluded that most of my problems were "technique" and not hardware related.

If anyone cares, these bits were made in China. I would have looked elsewhere if I had known before I ordered.

My experimenting (wife calls it playing) has led me to wonder which hole (counter sink or through bore) should be drilled first or if it even makes a difference. That too is probably a matter of personal preference and individual technique.

Dusty
I have always had the problem of countersink drift. Many of my countersinks end up elipical rather than round. SOOOOOOOO

When I want the finished project to be really pretty I always do the counter sink first unless I have one of those drill bits that drill and countersink at the same time.

After a countersink I have a perfect cone to guide the drill bit into a perfectly centered hole.

When I do this my countersink and drilled hole look perfect.

I don't know if that is the right way to do it but it works perfect for me.

Incidently I often countersink with a larger drill bit, then drill the through hole with a correct size. Usually this is even prettier since the drill bit angle is slightly different than a countersink and the screw usually is snugged in better.

[dusty]

The new countersink bits that I got from Lee Valley work OK.

They perform a bit different than I had expected but I do get a clean, round hole. They seem to work about the same whether I drill the through hole first or after I drill the counter sink.

I have sorta come to the conclusion that my original discontent was created by my own "poor technique". I drilled a lot of holes yesterday, trying to compare the various counter sink bits in a variety of scraps (reduced the quantity of those doing so). Making certain that drill speed is low and stock is held firmly in place make a lot of difference.

These new bits, however, do introduce a new issue. They can get clogged up with the debris. When clogged, they don't work so well, duh.

[ATTACH]18453[/ATTACH], [ATTACH]18454[/ATTACH]

[reible]

The new countersink bits that I got from Lee Valley work OK.

They perform a bit different than I had expected but I do get a clean, round hole. They seem to work about the same whether I drill the through hole first or after I drill the counter sink.

I have sorta come to the conclusion that my original discontent was created by my own "poor technique". I drilled a lot of holes yesterday, trying to compare the various counter sink bits in a variety of scraps (reduced the quantity of those doing so). Making certain that drill speed is low and stock is held firmly in place make a lot of difference.

These new bits, however, do introduce a new issue. They can get clogged up with the debris. When clogged, they don't work so well, duh.

[ATTACH]18453[/ATTACH], [ATTACH]18454[/ATTACH]

Hi Dusty,

When I look at your pictures it leaves me to believe you are getting dust coming out... I think you are running the bits too fast and or feeding to slow.

Up for another round of testing?

If so set the depth stop for the depth of countersink you want. Slow the rpm down and then feed fast. You should see more like shavings then dust.

Ed

[dusty]

Hi Dusty,

When I look at your pictures it leaves me to believe you are getting dust coming out... I think you are running the bits too fast and or feeding to slow.

Up for another round of testing?

If so set the depth stop for the depth of countersink you want. Slow the rpm down and then feed fast. You should see more like shavings then dust.

Ed

Thanks for the feedback!

Yes, I would normally expect shavings from this sort of cutter but
shamefully, I am guilty of having not disclosed all pertinent information.

These bits were clogged while drilling in some scrap mdf veneer.

After reading your comments, I went out and drilled a couple holes in real wood. These bits do produce shavings, all be it small shavings.

Thank you again for your keen eye and for your skilled observations.

Hopefully everyone learns as much from your postings as I feel I do.

[reible]

This is a post from some years back. Please note this is mdf and notice the shavings, or chips if you may.

http://www.shopsmith.net/forums/showpos ... stcount=19

Ed

[dusty]

This is a post from some years back. Please note this is mdf and notice the shavings, or chips if you may.

https://forum.shopsmith.com/viewtopic.php?p=27298&postcount=19

Ed

Very interesting, Ed.

I thought I was done but it appears not. So little time, so much to learn.

[dusty]

Holes in a piece of wood and in a piece of MDF all cut at same low speed.

Shavings or Dust

[ATTACH]18463[/ATTACH], [ATTACH]18464[/ATTACH]

[ATTACH]18465[/ATTACH], [ATTACH]18466[/ATTACH]

[greitz]

Maybe moisture content of the MDF has something to do with it?

Turning green wood usually gives long shavings, while turning the same wood species when dry gives smaller shavings, or sometimes small chips or dust.

I would expect Dusty's MDF has a much lower moisture content than Ed's MDF.

Just speculating...

Gary