Workbench Advice

[Marc Prudhomme]

Hello again gentleman,
I want to make a new top for my workbench in my home shop.I really want to make it out of maple but I really do not have all that time and I am just beginning so I do not want to get to involved.I have decided to make it out of (3) 3/4 MDF Panels glued and screwed together.The only problem I have is that I want to drill holes for bench dogs.I am afraid that I might hit one of the screws when I drill.Does anyone have any good advice on how to go about this?Will my vices bolt up strong on the MDF?If so what type of wood lags do I use and what is the pre-drill size?Do I really need to srew the MDF together,or can I just glue them together?
Any one with some good suggestions please feel free to chime in.Keep in mind that I want to go cheap and easy do give me a decent Bench.
Marc

[Robert Mahon]

An idea:
When setting the screws, place them on specific centers in a grid pattern. Then, when you want to place the holes bench dogs, you'll know where not to drill. Say you place the screws on 6" centers. Assuming the dogs will be placed on 12" centers, place the 1st of them 9" from the edge, which will be between the 1st 2 screws. Then go on 12" centers form there.
Also, a magnetic stud-sensor can help you locate the holes. If a screw is sensed, don't drill there.

[Marc Prudhomme]

Thks bob,
I was kinf of hoping I didnt have to do all that layout but unless I can get away with just gluing them together I have no other choice.

What about the lags for th vice.will it be strong enough mounted to the MDF.Any suggestions?

[Eric Mims]

I made my bench/assembly table from a sheet of 3/4 ply I had covered with 2 sheets 3/4 MDF. It's really heavy. I glued and screwed mine, but ended up taking the screws out after glue dried. If I did it again, I would just make some cauls or rig some pipe clamps from the ceiling to clamp the big surfaces together and forget the screws. I didn't put holes in mine, but I might. You can always try selectively reinforcing areas with hardwood if you feel the need.

Main thing is you don't want the screws to actually seperate the boards when gluing. And it's hard to tell in the very center of a big table..

[Marc Prudhomme]

do you think that the 3/4 plywood on the bottom is stronger for mounting the vice??

[Mike Heidrick]

do you think that the 3/4 plywood on the bottom is stronger for mounting the vice??

I would glue on a hardwood block (not even plywood in my opinion) to mount the vise into definately.

Are you going to have aprons that are wider than the top around the edges of the table? Put you hardwood (hard maple cut off) just on the other side of that apron, again doing the layout of where your vice will mount, and then glue and scew it there.

This is also a good time to consider recessing the rear jaw of your vice into the table and using the apron to cover it. This will give you the entire table apron edge to clamp too at the cost of the apron's width of clamp opening capactity.

[Eric Mims]

If I were to put a vise on my table, I would add a piece of hardwood. I only used the piece of plywood because I had an extra one.

[Marc Prudhomme]

Sorry mike but I really didnt understand what you said.Any pics or diagrams to help me.I am not sure what an apron is.I am guessing that that means the overhang where the base of my table is.
I would glue on a hardwood block (not even plywood in my opinion) to mount the vise into definately.

Are you going to have aprons that are wider than the top around the edges of the table? Put you hardwood (hard maple cut off) just on the other side of that apron, again doing the layout of where your vice will mount, and then glue and scew it there.

This is also a good time to consider recessing the rear jaw of your vice into the table and using the apron to cover it. This will give you the entire table apron edge to clamp too at the cost of the apron's width of clamp opening capactity.

[Ron Brese]

Marc I made my bench from a solid core door and put strips on the edge to provide a place for the bench dogs. I don't think the mdf will hold up very well in the stress areas around the bench dogs. If I were you I would either use a good quality birch plywood with solid wood banding or a door as I did.

Ron

[Marc Prudhomme]

So then I would have to notch a section of the bottom laminate out so I can glue and screw a 3/4 thick piece of hardwood to mount my vice on.Is that right?
If I were to put a vise on my table, I would add a piece of hardwood. I only used the piece of plywood because I had an extra one.

[Dewayne Reding]

I did something similar, and considered MDF at first. Plywood got the nod because it seems way more durable, and won't swell up too bad when I spill a coffee on it. Home Depot sells a birch plywood here for $28 a sheet. Not quite staining grade as it has pretty severe color variances in the grain. But it looks respectable. I think two sheets of it might equal 3 sheets of MDF. And maybe not. Just my opinion.

[Neil Bosdet]

I made mine out of a solid core door as well. The same process could work here for you on your MDF top. What I did was used some hardwood Maple flooring and attached it to the top. This would go on the top of your MDF. Use 3/4" flooring and it will add a bunch more stability for bench dogs. Layout your dog holes so you don't staple in those spots. Trim the whole top and add an apron (solid hardwood edge) around the entire top. Your finished top will be beautiful, strong and will look like solid wood. No one will know you have a MDF core. Finding cheap flooring for this amount of space should be a piece of cake.

[Neil Bosdet]

If you do a hardwood floor top like I suggested above, you could incorporate lag bolts into the top structure for your vice. They would protrude from the bottom and be very solid. Maybe epoxy the heads in place and then go ahead and add the hardwood top.

Another thing. I agree with Eric, use cauls instead of screws when you laminate your MDF sheet together.

[Marc Prudhomme]

Im confused,Ithought that the woodworking vices mounted from the bottom

[Dewayne Reding]

I like Neil's idea a lot. You could steal that much flooring on a closeout if you were a little patient.

[Neil Bosdet]

Layout the locations where the vice would mount to the bottom of your benchtop. Drill holes through your laminated MDF. Drill larger holes on the top side to allow the lag heads to be flush with the surface (you could chisel out corners to make the area square for extra holding power with epoxy. Drop lag bolts through with washers from the top. Expoxy the heads and smooth the epoxy flush with the surface. Hardwood you top. now you have lag bolts sticking out the bottom where you need to attach your vice. When ready just add your vice along with washers and nuts from below and you're done with mounting beneath the top.

[Marc Prudhomme]

great idea.Thats much better tan using lag screws fro the bottom. Thx
Layout the locations where the vice would mount to the bottom of your benchtop. Drill holes through your laminated MDF. Drill larger holes on the top side to allow the lag heads to be flush with the surface (you could chisel out corners to make the area square for extra holding power with epoxy. Drop lag bolts through with washers from the top. Expoxy the heads and smooth the epoxy flush with the surface. Hardwood you top. now you have lag bolts sticking out the bottom where you need to attach your vice. When ready just add your vice along with washers and nuts from below and you're done with mounting beneath the top.

[Marc Prudhomme]

what would be the best way to attatch the hardwwod flooring,glue or finish nails?

[Neil Bosdet]

I glued mine and angled 16 gauge finish nails through the tongue similar to a flooring stapler. To do it again I would layout the dog holes on the MDF (noting your spacing on paper and then glue and floor staple the flooring onto the MDF. You'll need to add an edge brace for the first couple of rows to make sure they stay put. If you premark where you will drill the dog holes then you can easily avoid stapling anywhere close and save yourself hassles and killing drill bits. Use round dogs like the ones from Lee Valley. I have them and they work great. Very easy to drill the dogs holes after the top is all finished.

http://www.leevalley.com/wood/page.aspx?c=1&p=31127&cat=1,41637,41645

[glenn bradley]

A spin on Robert's idea; determine where your dog holes are going to go and then make sure a screw isn't there. This would give you a more relaxed screw pattern.

[Jim Becker]

Drill larger holes on the top side to allow the lag heads to be flush with the surface (you could chisel out corners to make the area square for extra holding power with epoxy. Drop lag bolts through with washers from the top.

You don't want lag bolts for this application...regular bolts that can take nuts are the right fastener for this job. And you need to mount the vice before you cover the top to be able to tighten them properly if the top is going to be covered. Several layers of MDF will provide very nice support for the vices mounted in this way, however. Good solution!

[Marc Prudhomme]

Thanks guys,
I think I will be going with the 2 MDF and the hardwood flooring Idea.What type of glue should I use for the lamination?Should I glue the hardwood edging I plan to put around the edges of the table?(Glue and pipe clamps)

[Marc Prudhomme]

Thanks guys,
I think I will be going with the 2 MDF and the hardwood flooring Idea.What type of glue should I use for the lamination?Should I glue the hardwood edging I plan to put around the edges of the table?(Glue and pipe clamps)

[Richard Keller]

Not sure that MDF is the best choice here. I think that MDF may tend to crumble around the dog holes after a while. If your planing to re-make this bench from maple later when funds permit, I'd go for it though. I would just glue the MDF up, drill dog holes, and then drive long screws in from the underside. This would eliminate any need for a tape measure :)

Richard

[Travis Hirst]

I did the same as neil with my top. I used laminate flooring left over from doing my house. The great thing about this stuff is that when your doing assembly and glueing parts up, after the glue has dried it will come right off with just a little scrape. The other great thing is that if it gets gouged up just tear it off and put some new stuff back down and your good as new again.

Travis

[Marc Prudhomme]

travis,
Did you glue the floring material to the table?What type of glue did you use if you did??

[Travis Hirst]

I just used a little gorilla glue sparingly and then tacked it down with brads at an angle in the grooves before slipping the next piece on. It works great as a bench top because it really holds up well to pounding and beating and like I said before glue will just scrape right off when it dries. My bench only took about half a box so I have plenty more to replace it with when I need to.

Travis

[Marc Prudhomme]

Ya I found some nice oak 3/4 thick flooring on clearance for 30.00 for 21 sq ft.What was your flooring material?