Confusion On Fixing Edging To Workbench.

[pollys13]

Confusion On Fixing Edging To Workbench.

The workbench I'm making to learn various skills on see,
http://www.instructables.com/id/Buildin ... workbench/

I'm in a bit of a conundrum, the 40mm solid Beech worktop I bought as a top was £70 and having two big sheets of 19mm MDF cut was another 40 odd. So I'm £110+ in so far, with just these and feel committed to carry on.According to the designers plans the two 19mm MDF sheets are laminated together then screwed into the worktop. Screwed not glued, the designer said this way to allow any movement to take place. I decided on this bench design as it didn't involve any jointing of mortice and tenons, which at the moment I don't feel confident to make. Anyway I'd need a workbench to make them.... Catch 22 I think

People have expressed concerns about movement some more people than others about joining the MDF to the top with screws.As I say I'm sort of committed now so if goes pear shaped I will have to take it all off and stick several sheets of ply on top whatever, which cosmetically isn't so nice to work on. Yes I know its not a dining table but even so, I'd like a nice space to work on.

In the original design, he used two layers of MDF of 3/4" MDF edged with 1/2" oak and topped by a 1-1/2" thick edge glued oak IKEA countertop . I did buy an IKEA hollow core with 3mm Beech lamminated all round worktop.Then found for another £19 I could buy a solid Beech 2m x 62cm x 40mm for only another £19, so the IKEA went back and I bought the solid Beech one.

He cut oak strips off the IKEA top and glued these as edging to the MDF.
Now I'm thinking, of how to do this a bit differently.

I had my MDF sheets cut to the same size as my Beech top. I could trim the two laminated MDF sheets 1/2 inch all round the edges.Then get some Beech boards say 3/4" thick, first positioning the worktop all square inside the MDF and screwing the MDF to the worktop, so an equal uniform gap all round. Then plane and thickness the Beech boards to fill up that 1/2" gap exactly.Ripping the boards on the tablesaw allowing say 5mm to clean up any saw marking on the planer and sand edges, as have nothing set up to use a No 4. What advice do people have for putting edging on the MDF this way? Perhaps sealing the MDF edge up before using quick drying PVA. Or perhaps screw the edging into the MDF?

Or perhaps not trimming down the MDF but have a full height Beech board of 78mm which would cover the combined height of the Beech top and MDF, but then perhaps movement problems, glueing to the MDF and Beech top or counterbore screwing them together and filling up the counterbore with a Beech dowel plug?
I don't really know, so as ever any help and advice much appreciated.
Cheers.
"all men dream: but not equally. Those who dream by night....wake in the day to find that it was vanity; but the dreamers of the day are dangerous men, for they may act their dream with open eyes, to make it possible."
T.E. Lawrence

 

[MattRoberts]

I'd go for the former - trim the mdf, and then fill the gaps around the perimeter with beech. You can then plane the boards flush with the beech top. Just glue will be fine for the trim, but you can use a brad nailer as well if you like. Just be sure to tap the nails in deep so you don't catch them with the plane

 

[custard]

Two sheets of 18mm MDF screwed into a 40mm solid timber trip doesn't constitute a better workbench top than just the 40mm timber top all by itself. I get that the MDF adds some weight and thickness, but MDF is notoriously saggy, so it's not adding much in the way of strength or rigidity, which are the two qualities you really want in a bench.

Additionally, by fastening solid timber to MDF you're opening up the possibility of serious warping and splits. Screws may provide enough flexibility to avoid that, but then again they may not. Why take the risk when the MDF sheets aren't actually contributing much apart from the illusion that the bench has a thicker timber top than it actually does?

Put your MDF sheets away (they'll soon come in useful for your shooting board and other stuff) and reconfigure your design just with the 40mm timber top. Unless you're planning on parking a locomotive on your bench 40mm is plenty thick enough for all the projects you're likely to undertake. Just remember to do your hammering directly above a leg and you'll be fine.

But if you're determined to have a thicker top, then do what generations of craftsmen have done. Fasten a wide plank of Beech on the underside of your top along the front edge. There's no rule that a top has to be uniformly thick across its depth, and a 25mm thick x 150mm or 200mm wide board at the front will give you plenty of thickness for attaching a vice or drilling super secure dog holes.

Good luck!

 

[custard]

Two sheets of 18mm MDF screwed into a 40mm solid timber trip doesn't constitute a better workbench top than just the 40mm timber top all by itself. I get that the MDF adds some weight and thickness, but MDF is notoriously saggy, so it's not adding much in the way of strength or rigidity, which are the two qualities you really want in a bench.

Additionally, by fastening solid timber to MDF you're opening up the possibility of serious warping and splits. Screws may provide enough flexibility to avoid that, but then again they may not. Why take the risk when the MDF sheets aren't actually contributing much apart from the illusion that the bench has a thicker timber top than it actually does?

Put your MDF sheets away (they'll soon come in useful for your shooting board and other stuff) and reconfigure your design just with the 40mm timber top. Unless you're planning on parking a locomotive on your bench 40mm is plenty thick enough for all the projects you're likely to undertake. Just remember to do your hammering directly above a leg and you'll be fine.

But if you're determined to have a thicker top, then do what generations of craftsmen have done. Fasten a wide plank of Beech on the underside of your top along the front edge. There's no rule that a top has to be uniformly thick across its depth, and a 25mm thick x 150mm or 200mm wide board at the front will give you plenty of extra thickness for attaching a vice or drilling super secure dog holes.

Good luck!

 

[pollys13]

Two sheets of 18mm MDF screwed into a 40mm solid timber trip doesn't constitute a better workbench top than just the 40mm timber top all by itself. I get that the MDF adds some weight and thickness, but MDF is notoriously saggy, so it's not adding much in the way of strength or rigidity, which are the two qualities you really want in a bench.

Additionally, by fastening solid timber to MDF you're opening up the possibility of serious warping and splits. Screws may provide enough flexibility to avoid that, but then again they may not. Why take the risk when the MDF sheets aren't actually contributing much apart from the illusion that the bench has a thicker timber top than it actually does?

Put your MDF sheets away (they'll soon come in useful for your shooting board and other stuff) and reconfigure your design just with the 40mm timber top. Unless you're planning on parking a locomotive on your bench 40mm is plenty thick enough for all the projects you're likely to undertake. Just remember to do your hammering directly above a leg and you'll be fine.

But if you're determined to have a thicker top, then do what generations of craftsmen have done. Fasten a wide plank of Beech on the underside of your top along the front edge. There's no rule that a top has to be uniformly thick across its depth, and a 25mm thick x 150mm or 200mm wide board at the front will give you plenty of extra thickness for attaching a vice or drilling super secure dog holes.

Good luck!

OK, I'll leave out the MDF then. Though securing a Beech board to the underside of the bench, won't that introduce an element of warping also? Timber from two different sources perhaps not the same moisture content?
If you say no, then how wide and thick should the board be and it would be the full length of the board?
" 25mm thick x 150mm or 200mm wide board at the front will give you plenty of extra thickness for attaching a vice " The same for a tail vice? Would I be OK to use the MDF for the bottom shelf or again should I forget the MDF all together and use 19mm ply instead?

"all men dream: but not equally. Those who dream by night....wake in the day to find that it was vanity; but the dreamers of the day are dangerous men, for they may act their dream with open eyes, to make it possible."
T.E. Lawrence

 

[Racers]

The best thing to do is not to over think things, start using your bench and see what needs altering, no bench is perfect, and the closer to perfection you get the further you are away.

Pete

 

[Phil Pascoe]

^^^^ +1 This bench won't be perfect, nor will your next one.

 

[adidat]

I have an mdf top to my bench, it's easy to screw things too, very cheap so if it's replaced every 2 years it's fine, happy to get it stained with paint and oil etc, and just turn it over. just one screw in each corner sunk below the surface.

Interesting that you don't feel ready to cut mortise and tenons as this would really be the best time to learn. Large joints like those are hard to get wrong.

Adidat

 

[Phil Pascoe]

Don't talk yourself out of m&ts - I did the frame of this one -

(not the top) on the bench that my lathe sits on ... without a vice, a mortice chisel, or mortice gauge. I had one pair of sash cramps, bolted together to pull the joints up, then pinned them as I went. It is surprising what you can do if you put your mind to it.
(excuse the clutter - I'm in the middle of about six other jobs, and the bench is always first casualty )

Oh, and I forgot - working from a wheelchair.

 

[Eric The Viking]

+1 for the M+Ts.

I, too, did my first ones on the bench legs. Given it was about 25 years before I understood how to sharpen (thanks to this forum really!), and that I had NO power tools at all (well, a B+D drill), cutting them was blister-inducing, but I learned a lot.

You'll be glad you did, honestly.

 

[pollys13]

Uum, Okey dokey I'll do mortice and tenon it will save on the threaded bar and nuts.I'll be using my cabinet morticer for this and my bandsaw. Though first I have to get each machine set up and running properly I bought two inexpensive waterstones to clean any manufacturers marks on the outside of the hollow morticer chisels. I think I might need to get an auger file etc I've seen people using these to make the auger is really proper sharp, oh I got a pair of diamond cones for the chisels. Will have to get the bandsaw properly set up and tuned.

The finished size of the legs will be 95mm square, the rule of 3rds will come into the width of the tenon. Though as having to stretchers going into each leg I don't know if the mortice should be 1/3 the depth???

Morticing some say double cutting is ok some say not. I would have gone down the route of using M&T earlier but finding the information on setting up bandsaw and stuff took, is taking a while.

Been reading and Googling about bandsaw blade tension, one book says very often the machine tension gauge setting is very inaccurate. So that took me down the road into very expensive tension meters, I know about the twang method but felt that was a bit hit and miss. Then I looked at Mark Duginskis Bandsaw book, he strikes me as a genuine nice bloke and he said, blade tension inaccuracy on bandsaws gauges was a myth put out by the industry.
He went on two say in over 100 bandsaws he had tried all their tension gauges were accurate, further he also compared each machines tension gauge with 3 separate makes of blade tension meter ones that you fix on the blade and they all gave the same reading.
Thanks guys will plod on and use M&Ts
Ps have couple of Titebond

"all men dream: but not equally. Those who dream by night....wake in the day to find that it was vanity; but the dreamers of the day are dangerous men, for they may act their dream with open eyes, to make it possible."
T.E. Lawrence

 

[Racers]

Have a look at this video it explains a lot about M&T joints, ones that have lasted 400+ years.

http://www.pbs.org/video/2172740515/

Pete

 

[pollys13]

So doing it with M&T should I perhaps increase the height of the stretchers or incorporate a front apron? Is is basically going to be a carcass, frame if these are the right terms, so should I modify the design...... while I'm at it or might this open a whole new can of worms?

 

[custard]

Would I be OK to use the MDF for the bottom shelf

If it's supported all the way around, or at least on the two long sides, then one sheet of 18mm MDF will be fine for the bottom shelf. If it's not supported on at least the two long sides then neither 18mm MDF nor 18mm ply will be satisfactory, although you would get away with 18mm ply if it had stiffening battens screwed to the underside.

Good luck!

 

[mikefab]

The finished size of the legs will be 95mm square, the rule of 3rds will come into the width of the tenon. Though as having to stretchers going into each leg I don't know if the mortice should be 1/3 the depth???

1/3 to 1/2 of the thickness of the workpiece is a maximum for the tenon thickness not the size you need. I'd suggest 16mm tenons would be fine that's what I used on my workbench with 150×90mm legs. In terms of the length then just make them as long as you can before they bump into each other.

HTH
Mike

 

[pollys13]

The finished size of the legs will be 95mm square, the rule of 3rds will come into the width of the tenon. Though as having to stretchers going into each leg I don't know if the mortice should be 1/3 the depth???

1/3 to 1/2 of the thickness of the workpiece is a maximum for the tenon thickness not the size you need. I'd suggest 16mm tenons would be fine that's what I used on my workbench with 150×90mm legs. In terms of the length then just make them as long as you can before they bump into each other.

HTH
Mike

 

[pollys13]

I think I will rearrange the position of the stretchers so they line up with the outside face of the legs and also increase the height of the stretchers. As I have to rethink how my two screw vices are going to be fitted as not using the MDF under now.
Would it weaken the M&T joint if I put the stretcher tenon closer to the outside face of the leg?

"all men dream: but not equally. Those who dream by night....wake in the day to find that it was vanity; but the dreamers of the day are dangerous men, for they may act their dream with open eyes, to make it possible."
T.E. Lawrence

 

[pollys13]

Don't talk yourself out of m&ts - I did the frame of this one -

(not the top) on the bench that my lathe sits on ... without a vice, a mortice chisel, or mortice gauge. I had one pair of sash cramps, bolted together to pull the joints up, then pinned them as I went. It is surprising what you can do if you put your mind to it.
(excuse the clutter - I'm in the middle of about six other jobs, and the bench is always first casualty )

Oh, and I forgot - working from a wheelchair.

Hi Phil,
Are your stretchers half the thickness of the legs? Is that a sort of rule?
Cheers.

 

[pollys13]

Have a look at this video it explains a lot about M&T joints, ones that have lasted 400+ years.

http://www.pbs.org/video/2172740515/

Pete

OK

 

[Phil Pascoe]

Yes, the rails on mine are about half the thickness of the legs and the tenons are half the thickness of the rail, bare faced.