3/4" Holdfast in 20mm MFT?
- Thread starter onocoffee
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luvmytoolz
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onocoffee said:
If it's solid timber yes, if it's MDF I would say no! I use the clamps pictured in my MFT and I have to really be careful not too tighten too much as the MDF gives so much, and is really easy to destroy the holes. Even mild clamping deforms the hole to a degree I've found.
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Michael Kellough
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Sounds like a project for a 3D printer. Make sleeves that will reinforce/reduce the 20mm holes.
FOG is as good a place as any to get this answer. Confirmed it online, here:
https://www.fine-tools.com/holdfast.html
We have often been asked if these holddowns and holdfasts will also work in 20 mm holes. I will say here again clearly, no! It is a bad idea to use over-size holes as the contact between the shaft of the clamps and the bench top is much reduced if there is too much play in the holes. This both reduces the available clamping pressure that is possible, and will over time damage the edges of the holes, decreasing still further the holding power of the clamps.
As an aside, the Black & Decker Workmate bench has been around from the mid-1960s, and I read that over 20 million have been sold.
At any rate it is made on the 20mm hole system and all the dogs that are made for the Workmate should fit. The main advantage of these dogs is that they are incredibly cheap, some selling for 50 cents or 75 cents each. So for a few dollars you can have a lot of pieces handy for when the need arises.
The best thing about these are most are injection molded plastic parts and the dogs become the consumable product instead of your table top.
I have my late 70s era Workmate (practically indestructible), and I frequently have uses for it, especially for holding pieces for sanding. (I am not worried about accidentally sanding the bench dogs, so things go faster.)
https://www.fine-tools.com/holdfast.html
We have often been asked if these holddowns and holdfasts will also work in 20 mm holes. I will say here again clearly, no! It is a bad idea to use over-size holes as the contact between the shaft of the clamps and the bench top is much reduced if there is too much play in the holes. This both reduces the available clamping pressure that is possible, and will over time damage the edges of the holes, decreasing still further the holding power of the clamps.
As an aside, the Black & Decker Workmate bench has been around from the mid-1960s, and I read that over 20 million have been sold.
At any rate it is made on the 20mm hole system and all the dogs that are made for the Workmate should fit. The main advantage of these dogs is that they are incredibly cheap, some selling for 50 cents or 75 cents each. So for a few dollars you can have a lot of pieces handy for when the need arises.
The best thing about these are most are injection molded plastic parts and the dogs become the consumable product instead of your table top.
I have my late 70s era Workmate (practically indestructible), and I frequently have uses for it, especially for holding pieces for sanding. (I am not worried about accidentally sanding the bench dogs, so things go faster.)
waho6o9
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The holdfast is designed for 3/4" hole in a workbench top of a 1 3/4" thick or thicker. 6 1/2" reach. Maximum clamping 7 1/4" in a 2" thick benchtop. Patented. Made in USA.
https://toolsforworkingwood.com/store/item/MS-HOLDFAST.XX?searchterm=holdfast
These work well ^ HTH
https://toolsforworkingwood.com/store/item/MS-HOLDFAST.XX?searchterm=holdfast
These work well ^ HTH
Thank you, all. I guess I should note that my workbench is 1.5" plywood with the 20mm dog holes. I'm not necessarily in need of holdfasts but noticed that Woodcraft has them on sale this month.
[member=74278]Packard[/member] I didn't know that about the BD Workmate. I've got one that I've had since the 90s (or maybe late 80s). I'm gonna try those old plastic dogs tomorrow!
[member=74278]Packard[/member] I didn't know that about the BD Workmate. I've got one that I've had since the 90s (or maybe late 80s). I'm gonna try those old plastic dogs tomorrow!
Some of the dogs are set for the thickness of the Workmate top (3/4” or so). I don’t know if they will work with a thicker top.
The Workmate is very handy when you want a lower workin height. The small legs fold and lower the unit about 8”.
I have a bench top belt sander and some tasks are easier to do when looking down on the work. Also, the jaws on the Workmate adjust and make holding pieces for sanding with a hand sander easier.
If you keep the Workmate around and handy, you will find yourself using it for many tasks, and in many cases it might be the best bench in your shop for a specific task.
The Workmate is very handy when you want a lower workin height. The small legs fold and lower the unit about 8”.
I have a bench top belt sander and some tasks are easier to do when looking down on the work. Also, the jaws on the Workmate adjust and make holding pieces for sanding with a hand sander easier.
If you keep the Workmate around and handy, you will find yourself using it for many tasks, and in many cases it might be the best bench in your shop for a specific task.
