Drill Bit for Bench Dog Holes?

[Rob Luter]

Greetings to all,

I'm getting started on a new workbench for my new shop space. I've decided to make a varient of the Lon Schleining bench. The top will be Ash between 2" and 3" thick, with round dog holes. Any suggestions on the style of drill bit to use for these? I want to make sure the hole geometry is nice and crisp. I thought about a Forstener bit but I wonder if there's a better choice?

All input is appreciated.

- Rob

[Noel Hegan]

Personally Rob I would use a router for the dog holes with a shop built fixture to ensure complete roundness (I'm sure there's a better word than that). No limit on size and a far cleaner hole as well. If the top exceeds the lenght of cutters you have available complete the hole with a suitable lip & spur or spade drill bit.

[Jim Dunn]

I used a Forstener bit with a twist. I had a 3/4inch hardened bushing and bored a two holes in an aluminum plate to accept it. I used the plate to give me the spacing for the holes. The bushing provided a nice vertical surface for the bit. It stayed straight and bored a nice crisp hole.

[Jim Becker]

I used a brand new Irwin spade bit with the little cutting "wings" at the perimeter...absolutely clean holes on top and can be clean on the bottom if you clamp a sacrificial board to the top. Forsters will cut, but they create a lot of friction and heat...and that's not good for the cutter.

[John Thompson]

On the 3" thick top you are making, I would drill all holes with a Forstner, but drill only about 5/8". Then change to a spade and drill the remainder with a backing board as Jim mentioned clamped on the exit.

Sarge..

[Justin Bukoski]

3/4" router bit in a plunge router. Go as deep as you can and then finish the hole with an auger bit in a drill.

[Hank Knight]

Rob,

My bench top is 3" maple. I used a two-step process to drill my dog holes, but I'm not sure it was necessary. I started with a 3/4" spiral bit in a plunge router with a jig clamped to the bench top to locate the holes and keep the router solidly in place. The router bit was not long enough to cut the holes all the way through, but it gave me a nice, perpendicular hole to guide a drill bit to finish the job. I used a 3/4" brad point bit I got from Lee Valley (LV Item # 07J02.48 in the LV Catalog) and it cut a nice clean hole. Be sure to clamp a backer board where the hole exits underneath he bench top so you don't get any splintering. If you wanted to skip the router part, you could drill the holes in one step using the brad point bit. You would need to use a guide to make sure the holes started and remained square. I've done this by drilling a perpendicular hole of the correct size in a 2x4 with a drill press. Clamp the 2x4to the bench top, insert the brad point bit in the hole and go to town. Works fine.

Also, the Lee Valley hold downs I use have serrations on the shaft that goes through the bench top. The serrations are sharp and keep the hold down from slipping. I was afraid they would splinter my bench top when I removed the hold down, so I chamfered the rims of my dog holes a little to prevent splintering. I'm happy with the result.

Good luck with your bench.

Hank

[Dan Gill]

I used a 3/4 inch auger bit with a spacing and alignment block. Then I rounded over the top edge of the holes slightly with the router.

[glenn bradley]

I used a 3/4" bradpoint bit and a wood guide jig that I setup using the drill press for accurate spacing:

http://www.sawmillcreek.org/attachme...3&d=1180501803

[Rob Luter]

Thanks to all for the input.

I have a plunge router and may give Hank's method a whirl, but will also look into the Irwin Spade bits as Jim suggests. If these are like the old "speedbore" bits I've used in the past, I've had mixed results. In any case, I thought I'd finish with a 1/8 Radius roundover bit to soften the entry into the hole.

I'm in the planning stages now. Once I get done (could be weeks) I'll post some photos.

[Jeff Wright]

For a thorough discussion and photos on this topic, visit:

http://www.sawmillcreek.org/showthread.php?t=57406

[Bill Brehme]

Hey, aren't you supposed to tilt your dog holes a couple degrees towards your tail vise? So that the top of your bench dog is slightly leaning into the workpiece being clamped. I heard this compensates for any future wear in the dog hole which would allow the dog to tilt away .

I read that somewhere . If that were the case, I would incorporate this tilt into your drill bit guide.

[Gary Keedwell]

Hey, aren't you supposed to tilt your dog holes a couple degrees towards your tail vise? So that the top of your bench dog is slightly leaning into the workpiece being clamped. I heard this compensates for any future wear in the dog hole which would allow the dog to tilt away .

I read that somewhere . If that were the case, I would incorporate this tilt into your drill bit guide.

Bill...Most of the dogs sold already incorporate the angle on the dog itself so you can drill the hole at 90 degrees.
Gary K.

[Bill Brehme]

Ooohhh! Thanks for setting me straight on that Gary. I guess I should actually hold a bench dog in my hand before I start hacking into my near-future bench top. Or other people's for that matter!

[joe greiner]

I am new to this sight and not sure how it works. The problem, I have an older Wilton quick release woodworkers vise like the ones in all high school wood shops around the country. They are mounted to a large 2 1/4" thick hard maple table and have four work stations, one in each corner. I am looking for one bench dog for my work bench. They are t-shaped, with about a 7/8" solid round steel shank and a 3/8" thick rectanglar steel plate about 3" long and maybe 1" wide. I used to be a shop teacher here in Oregon and we had probably 30 of them in class. 30 times the number of schools in the country, there should be one left for me to use? Anyone know where I can secure one, I would be very appreciative for the information. Sincerely, Steve

Unless there's weird geometry you haven't mentioned, sounds like duck soup for a welding shop or a friend with welding capabilities. Perhaps make several with varying angles of the flat bar to the shank; one of them should be a best fit for square ends, and others could accommodate wear on the hole or other end angles. Probably faster than finding one by hunting and gathering.

Joe