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View Full Version : Adding bench dogs to solid-core door benchtop



Tom Henderson2
09-14-2008, 12:40 PM
Good morning everyone.

I'm a newb trying to develop some basic skills so forgive me if this has been discussed in the past. I did try the archives but didn't have any luck.

Have any of you ever tried putting bench dogs into a solid-core door benchtop?

My existing bench uses a solid-core door for a benchtop. I don't know exactly what the inside is filled with, but doubt it is strong enough to handle a bench dog.

I was wondering if it was feasible to bore a larger hole, install a plug made of decent material, and then then bore the bench dog hole into that plug.

Would a large dowel (like closet rod) be robust enough?

Is there an easier/better way?

Thanks!

-Tom in Ventura

David DeCristoforo
09-14-2008, 1:06 PM
"Solid core" doors are usually filled with loosely compacted wood fibers which, as you have correctly assumed, will not hold a "typical" bench dog very well. But you can get one like this:

http://www.highlandwoodworking.com/index.asp?PageAction=VIEWPROD&ProdID=7829

which comes with a metal insert. If you "through bolt" the insert, you should have plenty of holding power.

Bill Houghton
09-14-2008, 4:24 PM
If your door was pretty heavy, it may well be a glue-up of softwood with plywood faces - truly solid inside, in other words. One of these has served as my benchtop since the boys (now 36 and 32) were teenagers* and the bench dog holes I drilled through it have held up just fine. You don't really put a lot of pressure on a bench dog anyway - the wood will bend if you do.

I used the round Lee Valley bench dogs, and drilled 3/4" holes. I can't easily tell which holes have seen more use than others - there's been just very little wear.

If you're not sure - did you have to cut the door to length at all? If so, look at the end you cut. If you can see what look like 2x2s marching across continuously, you've got the good kind.

If you used it full length, before going to the time and hassle of installing "collars" in the bench top, buy a small diameter but long drill bit (about $6 at Sears for the 1/8"; probably a little more at your local hardware store), and drill from the edge into the body of the door in some inconspicuous place. You'll probably encounter a change in drilling difficulty after about 3/4" of drill - this is the edging around the door, often a hardwood. If, after this, the drill bit goes in REALLY easily, you've got a door filled with fluff, but if it's about as hard to drill as drilling, say, a pine 2x4, you've got real wood. Pull the bit out frequently to clear shavings, by the way.

*I can date the benchtop by the glue splotches left there by my older son, when he was gluing up some project and let the excess just slop on the bench. It's actually kind of hard to believe I've been using it now for nearly 20 years.

harry strasil
09-14-2008, 5:25 PM
if everything else fails, use a pony style pipe clamp with the pipe cut off and stick thru a hole and slide the end back on on the underside.

David DeCristoforo
09-14-2008, 6:32 PM
"...If you can see what look like 2x2s marching across continuously, you've got the good kind..."

I really hate to have to be the one to break this to you Bill :( but these have not been made for a really ling time now. Your sons are 32 and 36? That seems about right. 30-40 years ago you probably got one of the last "solid core" doors that actually had a wood core.

Tom Henderson2
09-15-2008, 12:51 AM
Hi Everybody=

Thanks for your thoughts.

This door is as David C describes -- filled with some sort of fairly soft stuff, judging by what has come out of the holes I've drilled in the past. Seems like fluffy MDF, if that makes sense.

David's suggestion would probably work, but I was really hoping for some bench dogs as much as a hold-down. So I'm still wondering if it would be feasible to epoxy in a large dowel, and then drill the 3/4" hole for the bench dogs in that.

But that does sound like a lot of work, since just one bench dog isn't worth much.

Someday, I hope to build a real bench but in the meantime I need to figure out how to get by with the existing setup.

Thanks again for your suggestions.

-TH

David DeCristoforo
09-15-2008, 11:19 AM
"...Seems like fluffy MDF..."

That's the stuff. "Fluffy MDF".... Love it... http://www.daviddecristoforo.com/Misc/rofl.gif
Maybe we should call it "ELDF" (Extra Low Density Fiberboard)

So the idea if having raw dog holes in not so good but what about the idea of attaching a solid wood edge to the hollow core door and drilling dog holes in that? I would think that a piece of 2 X 2 glued and screwed to the edge would work. Not a good long range solution but probably not too bad as a "stop gap".

John Schreiber
09-15-2008, 11:55 AM
My first thought is to give it a try and see. If possible, leave the dowels long on the bottom so they bear on the door skin there, and don't crank too hard on them. David's idea of gluing on a new front piece would work too if that would work with your vises.

Bill Moser
09-16-2008, 9:35 PM
Hi Everybody=

Thanks for your thoughts.

This door is as David C describes -- filled with some sort of fairly soft stuff, judging by what has come out of the holes I've drilled in the past. Seems like fluffy MDF, if that makes sense.

David's suggestion would probably work, but I was really hoping for some bench dogs as much as a hold-down. So I'm still wondering if it would be feasible to epoxy in a large dowel, and then drill the 3/4" hole for the bench dogs in that.

But that does sound like a lot of work, since just one bench dog isn't worth much.

Someday, I hope to build a real bench but in the meantime I need to figure out how to get by with the existing setup.

Thanks again for your suggestions.

-TH

Tom- I had similar problems with my first bench, made out of plywood and pressure-treated lumber. So I'm trying to think of how to get decent holding power for planing without building a new bench out of seriously thick hardwood. One thing you might do is to get a 3/4" thick by 2"wide by 6ft (or however long your bench is) strip of hard maple for the top, and a corresponding strip for the bottom. align those there you want the holes, and glue them in place on the top and bottom of the benchtop. You'll also need a 3/4" thick sheet of plywood or mdf to raise the rest of the top to the level of the maple strip. Its a tough problem. As they say, "it takes a bench to build a bench", so when you get to that point, you'll need all the help you can get from the bench you have.
regards
bill

P.S. Note that for mortising, you'll need to do that over one of the legs of your bench, or be prepared for some interesting wave action between the resonant frequency of your bench and your pounding out of the mortise!

John Sanford
09-17-2008, 12:59 PM
I used a solid core door for about 5 years as my benchtop, never had a problem with the dogholes. However, since the oak veneer wasn't all that thick, I simply faced the top of the bench with a sheet of hardboard, then drilled my 3/4" holes. I used the Lee Valley bench dogs, pups, and Wonder Pup, along with some stops made of Baltic Birch with 3/4" dowels.

Based on my experience, I'd suggest that you not worry too much about the dog holes, as there's a more significant shortcoming inherent in the construction of modern solid core doors. When installing lighting in my shop, my best friend stood out on the end of the bench top. Instant, and permanent droop. My bench base is a "standard" 4' long base, which leaves almost 3' overhang total. The end he stood on (right end, vise was on the other end) had approximately 2' of overhang, but still, there's no way that a timber bench top would have done that. The "stiles" of the door are stiff enough to support the weight of the door on the horizontal, but not stiff enough to support a whole lot more weight. So if you stick with the door, make sure that you support the beast.

When I sold my house and shut down the shop, I removed the vise and tossed the top. Doing so forced me to either a) get a new top or b) build a new top. I've done "A" (got a good deal) and "B" is planned.

harry strasil
09-17-2008, 1:59 PM
I have been giving this problem much thought, and have come to a conclusion if you are so inclined to use it.

1. Get some good oak flooring, the thicker the better.

2. Rip some of it down to the width of the door and using a good construction adhesive and clamps band the bench with it on all 4 sides.

3. Get some good quality 3/4 plywood and glue this to the bottom well.

4. Use the Oak flooring and the glue and laminate the top with the oak making sure to take the time to clamp each piece down and let it dry before adding another piece.

5. Rough cut the top and bottoms so that they are just proud of the edges.

6. Using an edging router bit with a bottom bearing, clean up the top and bottom laminations to your specifies, then light chamfer or round over the edges.

7. Drill all the holes you want.

8. It will look like a high dollar laminated work bench top.


FWIW

Larry Browning
09-17-2008, 2:00 PM
I will readily admit that I have only skimmed the ideas here, so if someone else has already suggested this, sorry for the repeat.

Why not do this? Drill an over sized hole, say 1", get a 1" maple dowel and glue that into the hole and cut it off flush. Then drill a new 3/4 dog hole into the center of that. I did this on my new bench when I drilled my 1st dog hole with a 7/8 bit by accident.:eek: You will have better luck if you mark the center of the dowel BEFORE gluing it into the bench.

Pam Niedermayer
09-17-2008, 4:18 PM
...Drill an over sized hole, say 1", get a 1" maple dowel and glue that into the hole and cut it off flush. Then drill a new 3/4 dog hole into the center of that. I did this on my new bench when I drilled my 1st dog hole with a 7/8 bit by accident.:eek: You will have better luck if you mark the center of the dowel BEFORE gluing it into the bench.

And what in the solid core door will hold the 1" dowel in place? There's nothing much there to glue to.

Pam

Tom Lauder
09-17-2008, 5:07 PM
Hi all

Might it be quicker to replace the top with a torsion box, I intend to use a torsion box for the top of my first bench and I am planning to put in a double stud in the place I want dog holes. This will allow me to drill 3/4" holes into solid lumber. It also avoids sawdust etc falling into the dog holes and filling up the torsion box. I am using Tom Caspers article http://web.archive.org/web/20030216032558/www.americanwoodworker.com/200111/projects/index.html for my inspiration.

Cheers
Tom

John Sanford
09-18-2008, 1:41 PM
It seems to me that if you want a quick, cheap, heavy, fairly flat workbench top you simply take a salvaged solid core door and put a sheet of hardboard (aka Masonite) on the top, and if you're really worried about the dogholes, put a sheet on the bottom. Just make sure your bench base is long enough to give good support (leave no more than 1' overhang).

Next up for quick, cheap and flat is to use a lamination of MDF or particleboard, again faced with hardboard. This will be a bit heavier than the solid core door, (a +), but takes longer to make (-), yet can be custom sized (++). Trim the edges with hardwood for both a better look and more durability. Liberally slather the thing with finish, insuring that you also put finish in your dog holes.

A torsion box sounds like a good idea, for a portable workbench. For a "permanent" bench, why? Its a lot of work to build a torsion box, weight is our FRIEND when building a bench, whereas one big advantage of torsion construction is the lower weight compared to solid construction. Furthermore, you have to pay close attention to make sure that your torsion structure doesn't have any non-planar anomalies (aka bumps). Note that I am referring to normal torsion box construction, not the "English Bench" form detailed in Schwarz's book.

Harry's idea sounds intriguing, but to me the only possible advantage it really has is if you have a source of cheap/free oak flooring and a cheap/free solid core door and you want the look of a solid lumber bench. The amount of work involved in his solution sounds to be the same, if not greater, than the work involved in building a solid lumber top. You're almost certain to end up with a top that looks great, and should perform as well as a solid lumber top, but you're restricted in sizing the top because of the characteristics of the door. Since you do have a modest amount of solid wood on the top, you can flatten it over time if needed, something that's not really an option with the first two construction methods above.

Larry Browning
09-18-2008, 1:50 PM
And what in the solid core door will hold the 1" dowel in place? There's nothing much there to glue to.

Pam

Well, I guess it would the "solid" part:confused: Most solid core doors have a partical board type center. I would glue it to that. Is that a problem???? I mean, how hard are you turning that vise handle?? Have others had problems doing this??
However, I am a bit "slow" sometimes.

Bill Moser
09-18-2008, 8:19 PM
Hi all

Might it be quicker to replace the top with a torsion box, I intend to use a torsion box for the top of my first bench and I am planning to put in a double stud in the place I want dog holes. This will allow me to drill 3/4" holes into solid lumber. It also avoids sawdust etc falling into the dog holes and filling up the torsion box. I am using Tom Caspers article http://web.archive.org/web/20030216032558/www.americanwoodworker.com/200111/projects/index.html for my inspiration.

Cheers
Tom

Tom -
That design might work well for someone who uses power tools primarly, but not hand tools, for several reasons. First is the weight. Try rough hogging out of a piece of red oak firewood to make boards for a drawer bottom, and I can tell you, an immovable workbench is essential! For me, my personal experience tells me that a 125lb workbench moves all over the place. Second, even with the torsion box construction, its held together with screws. I built my first bench with about 100 lag bolts, mostly in the 3/8-12" diam. range. As I torqued each one down to the max, I told myself: this thing is gonna be rock solid... Yeah right, within about 6 mos. the bolts had loosened to the point that I could rock the top back and forth by about a 1/2". Third, You can buy solid lumber for the price of the 2x4s and plywood, at least in my area. I can get red oak for the base, with 4x4 legs, and ash for a 3" top, for < $150 (oh, wait, add about $50 for gas to that to get there and back!). I'd have to laminate S3S stuff for the top and the stretchers, But I'll take that over pine and ply any day. Plus, If you build a charlesworth or roubo bench, you'll get to take a few real steps towards mastering the mortise and tenon joint, and end up with a really good looking, heavy, and long-lasting bench in the process
regards
Bill