workbench MDF top using bench holdfasts

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Forum topic by dpjeansonne posted 03-15-2013 08:36 PM 5211 views 0 times favorited 6 replies Add to Favorites Watch
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72 posts in 3238 days

03-15-2013 08:36 PM

Topic tags/keywords: bench mdf

I am looking onto building a bench using MDF layers for the top. I assume it must be a minimum 2 inches thick to use bench dogs and bench holdfasts.
My question is will MDF hold up using bench hold fasts or will the material be too soft over time and wallow out?
If this is an issue, will plywood be more acceptable?

-- Cajun Don, Louisiana

6 replies so far

View Benvolio's profile


148 posts in 1956 days

#1 posted 03-15-2013 11:59 PM

If you were dead set on using mdf for its low price and flatness (as I can’t think of any other reasons) then you’d definitely sacrifice durability…

however, if you were to sandwich your mdf between a top and bottom layer of 1/4 ply then you’d have the durability of ply and the other benefits of mdf.

the hold fasts will certainly dig into the sharp edges of the top and bottom of the bench holes and if you were using only mdf then I can’t imagine the holdfasts being very effective for very long at all. Cladding them with ply would add a longer life to them.

I’d also consider adding an inch or two to the strip of holes as I understand the more vertical the hold-fast – the more usable it is.

-- Ben, England.

View crank49's profile


4032 posts in 2996 days

#2 posted 03-16-2013 01:05 AM

My bench top is 3 1/2 inches thick. 4 layers of 3/4” plywood, a layer of 1/2” MDF and a replaceable 3/16” hardboard top. I know that all sounds like it would be more than 3 1/2” inches, but thanks to cheap a$$ undersized plywood its just a tiny bit less.

The cast holdfasts from Woodcraft won’t work on it, but the steel ones from Gramercy Tools work fine. They can be purchased from Tools for Working Wood. I haven’t had an issue with the holes wallowing out like I suspected I would. I did read in a recent tool evaluation in Fine Woodworking magazine that holdfasts have a problem when bench tops get thicker than 4”. The tool has to be able to tilt a certain amount to work.

View shipwright's profile


7992 posts in 2823 days

#3 posted 03-16-2013 01:22 AM

Here’s my plywood bench top.
It may work well for you.
No problems with holdfasts on it.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

View kdc68's profile


2658 posts in 2301 days

#4 posted 03-16-2013 01:29 AM

shipwright – wow your bench is awesome !...thanks for sharing your link and I will read the blog

-- Measure "at least" twice and cut once

View woodworker59's profile


560 posts in 2226 days

#5 posted 03-16-2013 01:41 AM

dpjean, I have my bench top made with 1” MDF for the top and bottom layer with 4 layers of 1/2” OSB glued and sandwiched between. I have been using it for two years now without any problems. I have not used any holdfasts, but have been using dogs and the vise to hold material in place without any movement in the dog holes. Its held up real well and is nice and flat.. I have not tried using it as the center layer so can’t comment on that. I am including a couple shots of my bench so you can see what I have done.. I wrapped it in Cherry and its been a work horse for me..

You can tell from all the shavings underneath it, that its seen a fair share of planing on it.. I would use the same top again if I were to make another.. Papa

-- Papa...

View Julian's profile


1347 posts in 2715 days

#6 posted 03-16-2013 02:01 AM

I used particle board and plywood for my bench top. I had it laying around and did not have to worry about getting the top flat. The bench top is 2” thick and I use hold fasts from Rockler. They hold great. One thing to keep in mind is that the hold fasts should not be very smooth. If they are they will not hold properly. If your hold fasts are smooth, just rough them up with sand paper.

-- Julian

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