Using a Forstner Bit in the OF 1400EQ for dog holes?

Ripcurl

Member
Joined
Nov 21, 2011
Messages
9
I am currently in the process of constructing a new workbench.  The plan is to use the 3/4" Round Dogs and was wondering if putting a Forstner bit in the 1400 and, using the guide rail, could drill the dog holes in line in the top. I have a specific layout I want to use which has holes too far from the edge for my drill press.  If so any ideas on the speed setting?  The top is going to be 3 layers of 3/4" birch plywood with a 5/16" Maple veneer on top. Any info on this would be greatly appreciated. Thanks.    -Rip
 
Forstner bits operates at very low speed (2,000 -3,000 RPM). Use 19mm hinge boring bit instead. You'll need 10mm -1/2" adapter also.

VictorL
 
Rockler has a series of carbide tipped Forstner bits with 3/8 shanks. I was able to get a collet for my Bosch router, cut the shanks to an acceptable length and use them at the slowest speed. They worked very well. Festool's door hinge bits are essentially Forstners. Steel bits? Forget it.
 
IIRC, we had a thread discussing doing this for workbench holes and somebody (was it Kreg?) said they'd found a source for 19mm plunge bits for the router.
 
Ya my main issue was the speed. Had talked to someone a while back who had tried something similar.  Spiral it is. Thanks for the replies that was super fast! I just joined here, seems like a pretty awesome resource.    -Rip
 
Spiral router bits are also not the best solution for plunging holes this size. With a down-cut spiral, you will get excessive tear-out and unexpectedly fast feed rates. With an up-cut spiral, you will get unpredictable jumps in your router. They are not really well suited for boring.

Your best bet it to go back to the forstner bit with the correct rpm (non-router).
 
Rick Christopherson said:
With an up-cut spiral, you will get unpredictable jumps in your router. They are not really well suited for boring.

Your best bet it to go back to the forstner bit with the correct rpm (non-router).

Rick, not my experience but it was only one time.  I noticed that I had drilled (spade bit) many of my dog holes crooked -- I didn't own a plunge router when I built my bench.  I went back and expoxied 3/4" dowel in the holes and used my Festool router mounted on the track to redo the holes.  No jumps, fed slow, worked great.
My top is 3 layers of MDF, perhaps that contributed to the posititve outcome, but of course I was taking out a lot of the birch dowels as I straighted out the bores.
Jay
 
Rick Christopherson said:
Spiral router bits are also not the best solution for plunging holes this size. With a down-cut spiral, you will get excessive tear-out and unexpectedly fast feed rates. With an up-cut spiral, you will get unpredictable jumps in your router. They are not really well suited for boring.

Your best bet it to go back to the forstner bit with the correct rpm (non-router).
 

With all respect, Whiteside has a 3/4" bit (#1085F), 1/2" shank, 1 1/4" cutting length, 3" OAL, with a carbide boring point that should be ideal for this application.  Whiteside also has a 13/16" bit (#1090), 1/2" shank, 1 1/4" cutting length, 3" OAL, NO carbide boring point, that could be reground down to 20mm (0.787402").  Amana offers similarly-sized bits (#45440 - 3/4" and 45444 - 13/16"), but without a carbide boring point. 

[smile]
 
Spark and Jay-

That was what I was thinking, only concern was the potential for tearout and jumping around... so that does sound like exactly what I need, (#1085F).  Calling the store to see if they have it in stock so I can start doing some testing. Thanks for all the responses, if they do will post the results good or bad.  -Rip
 
Hi, I've been through this myself.  As stated above, Forstner bits and routers are a recipie for disaster.  I tested a Forsnter bit with a hand drill in my 2-1/2" thick ash top and I might as well have been drilling into concrete.  I wouldn't be surprised if I would have burned out my drill motor if I tried the whole job that way.  Also, the little press stand I was using to maintain perpendicularity to the top was worse than worthless.   [tongue]

A spiral upcut bit on a router will make the cut very well - it bores fast and the router will maintain perpedicularity.  This option does have two drawbacks (1) router drift and (2) incomplete bore depth.  The best way to address the drift issue is to fix the router in place in some way.  I have a Festool system but even on the track, it drifted a bit, no matter how well I tried to hold it in place.  Later, I saw a video of a guy who made a template with a cutout the exact profile of the router base.  The template was scribed with vertical and horizontal lines that were aligned the dog hole marking lines scribed on the bench top.  Place and fix the template (clamps), set the router inside the template, and plunge away drift-free.

Which brings us to problem (2).  The 1400 with my upcut bit would not plunge to the full thickess of the table.  I tried the Forstner option again, but same as above.  So, I purchased a 3/4 Colt brad point bit and first fixed that to my T15.  Waaayy too slow.     [sad]  So, I brought out my Big Gun, an ancient, solid aluminum bodied Thor drill that has one slow speed and an ungodly amount of torque.  I used to use this drill to bore auger bits through 2-3 railroad ties or landscaping timbers.  It did not let me down.   [big grin] The one thing I had a problem with was tear out.  Of course this is on the underside of the table, but even with a hardwood backing board, I could not prevent it entirely.   [mad]  I probably should have finished with a different bit, but I was losing patience.

Or maybe you could make a custom 2 foot x 6 foot table for your drill press!

Good luck with it.

 
I would take a bit of an unorthodox approach to this problem.

Before you laminate the plywood, drill all your dog holes in the top layer- the 5/16" maple. Then glue it to the second layer- the 3/4" plywood- and the already drilled hole will provide a guide for the forstner bit so that you can use it easily in a hand drill. Continue with the next two layers of plywood.

Richard.
 
Another approach that worked for me is to Drill a 3/4 inch hole in a 2 inch cube ( actually the "cube" can be of any dimension and can be a rectangle instead of a cube) of hard wood on my drill press so there is a guide to drill a perpendicular hole.  I then used - at various times and situations - a twist drill bit, a spade bit, a brad point bit and a forstner bit (Colt Maxi is my favorite) to drill the holes in the work bench top with a hand drill - corded or battery - with excellent results.  This method is quite cheap ( just like me). 

HTH  Joe
 
I have a laminated top and drilled the holes after the glue-up was completed (see above).  In retrospect the best thing to do might be to drill the holes in partially glued sections, say 8" wide, so I can get it on my drill press.  On the other hand, that implies some pretty precise final glue-ups afterwards.  Dunno.  You know, every solution creates a new problem...
 
Here is a great way that you can do what you want. First if you have it take the LR32 system and guide rail and use the pointy 5mm bit to accurately mark all your holes for your top. Doing this will give you a very precise alignment. Once these (pilot holes) are drilled you can follow up with the forstner bit in the proper drill for it. I have obtained very accurate results with the above method.
 
TomGadwa1 said:
Here is a great way that you can do what you want. First if you have it take the LR32 system and guide rail and use the pointy 5mm bit to accurately mark all your holes for your top. Doing this will give you a very precise alignment. Once these (pilot holes) are drilled you can follow up with the forstner bit in the proper drill for it. I have obtained very accurate results with the above method.

Why not skip a step and start with the bit I linked to above? Then your drilling one hole instead of two, and still using the LR 32.
 
Ripcurl said:
I am currently in the process of constructing a new workbench.  The plan is to use the 3/4" Round Dogs and was wondering if putting a Forstner bit in the 1400 and, using the guide rail, could drill the dog holes in line in the top. I have a specific layout I want to use

I bought a 20mm straight/mortising bit from Festool (# 490971 or similar model now discontinued) and have drilled hundreds of holes with it for home-made jumbo MFT tops.  And I've used it for ploughing grooves and rabbets.  It's a real workhorse, well worth the money.

BTW, when drilling holes for MFT tops, I've marked the locations with penciled lines and just eyeballed it after that with the router on the guide rail.  So far, every pair of holes has been spaced at 96mm +/- 2mm on center.

Hope this helps.

Regards,

John
 
Back
Top