DIY MFT-style workbench thickness concerns - help needed

[davismeow]

Hi folks,

So I’ve currently got a workbench mounted to a wall in my garage which folds down on a hinge for when I need it. The surface dimensions are 4’x6’, and the top consists of a 3/4” MDF with another 3/4” plywood layer glued/screwed below it.

I’ve been thinking about upgrading it to have 20mm dog holes like the Festool MFT workbench. I would plan to use this with my tracksaw, for assembly, etc. However, from what I’m reading online the thickness of 1 1/2 inches is not considered optimal for an MFT-style workbench as tool compatibility is reduced. Supposedly an MFT style bench should be 18-24mm thick.

I realize that with my bench I wouldn’t be able to use the Festool ratchet-style clamps as the longer depth means I wouldn’t be able to fit them through the dog hole (due to their L-shape), but would there be other downsides to having a thicker top like mine? It seems like most dog hole accessories just insert into the top, but I haven’t been able to get clarity on whether there are other issues with a thicker top.

If any of you have a thicker top with 20mm dog holes like the MFT, please let me know what pros/cons you’ve discovered with that setup. Appreciate any and all guidance/critiques/etc. Thanks so much.

-Dave

 

[MikeGE]

Welcome to the FOG, Dave!

You won't be able to use the L-shaped clamps, as is, but the accessories that use the 20mm hole should work fine. One of my friends has a workbench similar to yours, and he modified his clamps so he could use them. He ground down the little protrusion on the end of the clamp that prevents the sliding piece from coming off. The L section is passed through the table from the bottom and the moveable piece is slid back onto the clamp. If he's not paying attention when he loosens the clamp, the L piece will drop to the floor, but at least he can use his clamps in the thicker table.

 

[Cheese]

Here's one of my benches with a 1-1/2" thick maple top. The only issue is that the clamps need to be separated and installed from the underside. I've been using this for the last 9 years and have no issues with it.

 

[woodferret]

There are also Bessey KLI20-MFT-SET and the Festool MFT-HZ 80 that are top-access only clamps. Enjoywood on Banggood also sells a MFT-HZ 80 style clamp. I actually like those more than the Festool ones.

 

[WillettBarrel]

I had a 1.25" thick top for a while; eventually I switched to a 18 mm top. Accessories that have counterbalance screws on the underside of the MFT weren't long enough. This would be Festool's surface clamps and VAC SYS MFT plate. That said, there are non-Festool branded options for both which don't require any counterbalance from underneath.

If you already have clamping elements for an 18mm top, then I'd go that route. If you already have a thicker top and would be buying new clamping elements either way, sounds like you're on the right path.

 

[davismeow]

Thanks so much @MikeGE, @Cheese, @woodferret and @WillettBarrel for the warm welcome and your replies. Sounds like there isn’t any reason why I can’t move forward with this, and I’ll take a look at some of those other tool options from Banggood/Bessey/etc. Looking forward to getting this done.

 

[squall_line]

I had a 1.25" thick top for a while; eventually I switched to a 18 mm top. Accessories that have counterbalance screws on the underside of the MFT weren't long enough. This would be Festool's surface clamps and VAC SYS MFT plate. That said, there are non-Festool branded options for both which don't require any counterbalance from underneath.

If you already have clamping elements for an 18mm top, then I'd go that route. If you already have a thicker top and would be buying new clamping elements either way, sounds like you're on the right path.

I've yet to use the screw to secure the Clamping Elements. The first time I used the MFT plate for the Vac SYS, I think I tried to use the screws to hold it down, but I've never gotten in a situation where I'm wrenching on it hard enough to get it to fall over since then. YMMV, of course.

 

[WillettBarrel]

I've yet to use the screw to secure the Clamping Elements. The first time I used the MFT plate for the Vac SYS, I think I tried to use the screws to hold it down, but I've never gotten in a situation where I'm wrenching on it hard enough to get it to fall over since then. YMMV, of course.

Agreed. The clamping elements are probably the least used accessory I have for the MFT. And even then, I only see need for the counter balance if the slight lift created by the clamp were an issue, which it's not been for me more than once or twice.

For VAC SYS, I use it every time. I fold mine under the table when not in use. Certainly agree there is no sense in wrenching them down, or even using both counter balance screws. But I have had VAC SYS tip over without them, so I always throw one on there when in use.

I also use the same part to secure my lunch box planer to a MW1000. So, I do think they're a useful part, in general. But not one I'd recommend throwing out a perfectly good bench top just to make use of.

 

[onocoffee]

I have a 3' x 6' workbench with a 1.5" plywood top that I built years ago. Modified it last year with the 20x96mm dog holes. I mostly use the Festool MFT-HZ 80 clamps in these and they work pretty well.

And "pretty well" mainly because I did the dog holes the hard way. Plotting a grid and drilling the holes by hand with a 20mm Fisch forstner and the CSX 12 - so they're not perfectly vertical in spots. I had to use a long 20mm drill bit to "widen" them slightly and now they work "pretty well". They can be a little tight when inserting or removing but once in and clamped down, they're perfectly fine. I also use UJK and TSO bench dog perfectly well - and recently bought the Bessey ratcheting clamps with the 20mm dog inserts (I think it's the same that woodferret referenced) but I haven't used them yet.

If you make your own and want to use it to cut accurate 90s with the track saw, I think you'll best be served using the UJK Parf Guide. That seems to bore a precise grid. I didn't design my bench to do that and I don't know if I would have the confidence necessary to use it in that manner as some of the dogs are not perfectly aligned.

My bench was also made with construction grade ply and I think if you wanted to do it with ply, it would be better to go with better quality ply and back it up when boring to prevent tearout - mine had quite a bit of tear out on the underside. And remnant pieces of ply can block the dog holes, which then need to be addressed. I think those who make it with MFD do not have these issues.

 

[davismeow]

Thanks @onocoffee. I do plan on using the UJK Parf Guide. Worst case, I can replace the top altogether if I can’t make it work with the mdf+ply bench I already have. We’ll see.

 

[Steve1]

I use steel dogs and eccentric or tapered side-clamps more often than the ratchet clamps, but the ratchet clamps can be handy.
So having a thick top is not the end of the world.