M20 hex bolts = super mft dogs

[Northernlight]

As the bolts are around 19.5-19.7mm around the threaded part of the bolt they seemed ideal as cheap dogs. Secured with a bolt and washer from underneath I find them to be more than accurate enough for my needs. The head vary in diameter from 30.05mm to 30.10mm. And that feels good enough. Also the top of the threads next to the bolt head there seems to be a cone shape that centers the dog?

 

[overanalyze]

Interesting idea! Thanks for sharing.

 

[duburban]

Good ideas are always the simplest. Very resourceful, good thinking.

 

[Northernlight]

Got started on an end grain cutting board made of beech.

 

[Zacharytanner]

What are the thickness/dimensions of your boards

Frank

 

[squawkin]

That's a great idea. I think I have some in my bucket of bolts.

 

[Northernlight]

What are the thickness/dimensions of your boards

Frank

I would imagine 20mm or so. It's the mft 1080 top.

 

[yverof]

Hello
I bought longer ones and cut them and it fits perfectly.
Yverof[attachimg=1][attachimg=2]

 

[Northernlight]

Hello
I bought longer ones and cut them and it fits perfectly.
Yverof[attachimg=1][attachimg=2]

Perfect )

 

[Enrico74]

I thought about this idea of using 20mm bolts the whole week.
I have a bunch of these and checked they were fitting well, and they did actually.
Then I remembered about that domino jig I saw recently: http://www.lairdubois.fr/creations/484-la-dominoteuse.html

I spent some time on the CAD software, fired the 3D printer up and ended up with this:

The shape is computed using the golden spiral formula, the bolt being at the center of the spiral.
The hex recess is adjusted so there is almot no play when the bolt is fitted.
I double taped some P120 sandpaper on the side to get a better grip.

It works so well, it can stand manual handplaning.

With a left and a right version, it is quite versatile and can be combined with other festool accessories.

Thanks again, I would not have thought of this without you

PS: for those who noticed the fuzzy surfaces I got on these, it comes from the extruder motor that is about to give up...