Router Bit for Benchdog Holes

[Jonathan Spool]

I have not been able to find a 3/4" spiral upcut bit with a 1/2" shank. I was hoping to find one with a substantial length as I will be using it to plunge cut benchdog holes in my 2.75" thick bench top.
I would appreciate it if someone can point me in the right direction.
Thanks
Jonathan

[Brad Wood]

thats a pretty long bit. what about a forstner bit? Personally I use my hand drill with an auger bit.

[Alex Shanku]

Spade Bit.

[Ken Platt]

I was just thinking today that I should look around for a 3/4 inch spiral bit, as a new workbench is my next project, and I'm thinking of a full grid of dog holes.

I too had seen using the router advocated for this in order to get good straight holes. I just looked through my bit collection, and I do have a 3/4 inch mortising bit. I figure once I get the hole maybe 3/4 inches deep, I can finish up with a regular bit which will be guided straight by the top of the hole.

Or, with luck, we'll get some other suggestions.

Ken

[John Schreiber]

Spade Bit.

+1
Cost is low and it worked great.

I had an old "turn your hand drill into a drill press" doohickey like this (http://www.amazon.com/Wolfcraft-Attachment-4-Inch-8-Inch-Drills/dp/B000JCIMEA/ref=pd_cp_hi_0?pf_rd_p=413863601&pf_rd_s=center-41&pf_rd_t=201&pf_rd_i=B0000E6TM6&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1HAATDDC0931F08VQ9D0). I was able to mount it to a jig and slide that along my new bench. Each hole I drilled was indexed off of the one I had drilled before it. Without one of those doohickeys, you could use drill an accurate hole in a block of wood and use that as your guide to drill the dog hole.

[Tony Bilello]

Just about any style drill bit should work. A Forstner will give a smooth cut and a spade will give a rougher cut. You can only be so accurate in order for the dogs to be easily inserted and removed. Too accurate and everything will stick in humid conditions.

[James Adinaro]

Here ya go. (Hope it's OK to post this link!)

http://www.woodcraft.com/product.aspx?ProductID=03K53&FamilyID=1396

I just used this same bit to bore the holes in my 3 inch bench. It didn't go all the way through, but got me far enough down that I didn't worry about the drill bit wandering.

It's HSS, not carbide, but it held up fine for the 40 or so holes in hickory, and I got no splintering or tearout on the top.

[Greg Hines, MD]

Here is how I did it. I used my plunge router, mounted to my router plate, which allowed me to clamp it in place, and for registration from one hole to the next. I then used a Bosch 3/4" straight bit, and plunged as deep as I could. That was about 2" deep. I then used a hand drill and 3/4" auger bit to complete the hole, now that I had a straight and square starter hole. It worked like a charm.

Doc

[glenn bradley]

I tired quickly of irregular results from (my ability in) drilling with a variety of bits. They got the job done but once I got the Onsrud bit James mentions and used a piece of scrap as a spacer as Greg mentions, I was much happier.

[Ralph Barhorst]

I got a 3/4" endmill with a 1/2" shaft from ebay. They work great for drilling dogholes with a router for a bench. I just checked and your can bid on four bits for $30.00. That is just $7.50 each. These are HSS and not carbide but they will easily last long enough for most uses.

There is also a two flute endmill for $7. I prefer a 2 flute bit.

[Jonathan Spool]

Thanks everyone for some excellent ideas and links. I once stumbled upon a post refferring to a bit set where one bit was standard length, and the second bit so long it extended from the base of the router, but made to finish up the second cut of the hole. Since it is the top 3/4" that I am most concerned with regarding hole acuracy, i will probably stick with using the router for the initial cut, and the follow through with a drill.
I was going to mak the holes on 6" centers. Is there any sensible reason why MFT tables holes are on 3.75" centers?

[John Schreiber]

The holes can be any distance you like so long as it is less than the travel of the vise you are using. The closer they are the less you have to move the vise though. Mine are 3.6666" and that works great.

[Jonathan Spool]

Thanks John. That makes for a lot of holes!

[Greg Pavlov]

+1
Cost is low and it worked great.

I had an old "turn your hand drill into a drill press" doohickey like this (http://www.amazon.com/Wolfcraft-Attachment-4-Inch-8-Inch-Drills/dp/B000JCIMEA/ref=pd_cp_hi_0?pf_rd_p=413863601&pf_rd_s=center-41&pf_rd_t=201&pf_rd_i=B0000E6TM6&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1HAATDDC0931F08VQ9D0). .....
That should work but be careful if you go this route: I had one of these disintegrate on me. I was trying to drill 1" holes through some thick maple (this was not an ideal way to do it but I didn't have much choice at the time).

[Greg Hines, MD]

Someone here has most of the holes 6" apart, except for the first few inches, which are closer together, like 2" -3". That is what I am going to do when I get some Wonder Dogs.

Doc

[Doug Shepard]

LV has a 3/4" brad point that works very well for dog holes
http://www.leevalley.com/wood/page.aspx?c=2&p=42247&cat=1,180,42240

[Anthony Whitesell]

Ralph,

Routers spin pretty fast (25,000 RPM), how than most metal cutting equipment I've seen. How fast can you or should you spin the endmills?

My current plan is a 2x glue up with a replaceable 1/2" MDF top wrapped in hard wood (I haven't decided on Yellow Poplar or Hard Maple yet). To be able to drill the benchdog holes in the next MDF top, I'm going to drill 1" diameter 1/4-3/8" deep holes in the bottom, then use a guide bushing and the 1" hole to align the router and drill the holes through the bench and top with the 3/4" bit.

Thanks.

[Cole Dunlay]

When you cut the holes, just be sure to clear the chips. Plunge down until the ends of the flutes are close to the benchtop and then pull out. Then plunge down a little further. Repeat this until you've reached the limit of travel of your router. If you don't clear the chips you run the risk of the bit binding in the hole. I talked to a man who did this and the bit came out of the hole and trashed his benchtop. He was lucky - it could have been him.

Cole

[Greg Hines, MD]

Ralph,

Routers spin pretty fast (25,000 RPM), how than most metal cutting equipment I've seen. How fast can you or should you spin the endmills?

My current plan is a 2x glue up with a replaceable 1/2" MDF top wrapped in hard wood (I haven't decided on Yellow Poplar or Hard Maple yet). To be able to drill the benchdog holes in the next MDF top, I'm going to drill 1" diameter 1/4-3/8" deep holes in the bottom, then use a guide bushing and the 1" hole to align the router and drill the holes through the bench and top with the 3/4" bit.

Thanks.


The problem I would have with this arrangement is that when you go to cut through the top, it could blow out. Then you get to look at the ragged edges forever. If this is what you intend to do, you might want to think about drilling your 1" hole in a piece of MDF or plywood, clamping that to the top of your benchtop, and then routing as above. One thing, however, would be the loss of the thickness of your guide piece in height of your router bit. I did this with a different project using just 1/4" hardboard, so that I got as much depth as I could with my router.

If you do intend to do it from the bottom, at least clamp a backer board to the top side of it, to help prevent chip out.

Doc

[tom coleman]

forstener bit in hand held drill worked fine

top is three layers
3/16 hardboard
3/4 mdf
3/4 cab grade plywood scraps

[Anthony Whitesell]

I bailed on this method when I asked the question: How far does my plunge router travel? The answer was a measily 1 7/8". Not far enough to plunge cut benchdog holes for me.

Otherwise, I was going to get a 6" overall length milling machine bit from eBay and put it in the router on the lowest speed.

[glenn bradley]

I used the Onsrud that James shows. Worked great, no tired arms or overheated drill motor. The Milwaukee plunge goes 2-7/8" and I finished it up with a drill bit for my 3" top.

[Chris Friesen]

Otherwise, I was going to get a 6" overall length milling machine bit from eBay and put it in the router on the lowest speed.

I would be very hesitant to put a bit that long into most routers.