Hold downs


#1

Has anyone posted or come up with a small ‘hold down’ that would push into the holes in the honeycomb, that could be pushed down to grip, then twisted to release ?
Or now that I’ve thought of it, is it up to me ?
:upside_down_face:


#2

I haven’t made one, but since the holes in the crumb tray are not circular, I think you could make something “T” shaped that would only come out one way. It would probably need to be more “t” shaped so that it is bracing against the bottom of the crumb tray.

But you would insert it, twist it to “lock” and then twist to remove.

Another idea is to just have “plugs” that are the shape of the holes with a little taper on the sides, Friction fit, but just might be a little easier to engineer.


#3

And from henry:


#4

Both good tips. I do a bit of silicone rubber/rigid polyurethane moulding, so I might do a combination of PU with a metal insert to get a suitable shape.

John


#5

I had Henry’s register guides in the back of my mind, but I don’t remember a hold down version that might help with ply warping, for example. Where the warp was too much for magnets, I mean.
:upside_down_face:


#6

I find that magnets do everything I need to hold materials down, and have yet to need a pin for the crumb tray. I use bar magnets to butt thick materials against and bars or discs to hold thinner materials in place, depending on the desired effect.

Keep in mind that the crumb tray can move, so you won’t get perfect registration with pins/pegs in the tray. From where I stand, that’s the only use case that comes to mind for pins, and it just can’t work.

What sort of thing do you need pins for? I bet there’s a use case I am not considering or haven’t come across yet.


Need Help: Ideas for bed clamp or jig for warped wood
Gettin oddly jiggy with it
#7

Warped non-PF grade 1/8" ply that’s been laying around in my garage for about 6 months !

:upside_down_face:


#8

Right, so I find that with proper magnets I have yet to find 1/8" I can’t unwarp. I stack 2 magnets on each other, and they just yank it down. Hang on, I’ll go get a picture of my magnet rigs, I already stack 2 magnets in each unit.

Here we go:

I tape my magnets up to protect them and make them easier to pick up, and find that the discs are ridiculously strong. The bars are nice and narrow for laying right along the edge. The discs, being really thin, can be stacked with another pair so that you get 4 stacked on top of your piece. It’s really very strong.

Ymmv, but so far, so good!


Material Fasteners (Hold Downs) - Sick of Using Duct-tape
#9

I’m impressed. Look forward to the photos and a source for the magnets.
John


#10

i use magnets from old hard drives and they do a great job of pinning down warped wood. and if you leave them on the metal plates, you can put the magnet directly on the crumb tray and have the play resting on top of the edge of the material, getting a stronger hold.


#11

Ah, sources. Amazon. Specifically:

and

The discs are rated with an N number, the bars aren’t. I get the feeling that the bars, while strong, aren’t as strong as the discs – they may be N35 instead of N52, if I were to order more, I might look for N52 bars (if they exist).


Material Fasteners (Hold Downs) - Sick of Using Duct-tape
Neodymium Earth Magnets to flatten Material
#12

I designed some T-pins for the PRU, but wasn’t real happy with how they worked, so let it go and tried something else. :slightly_smiling_face:


#13

I’ve bought a bunch of magnets from here. You have a very wide range of shapes, thicknesses, pull-direction and strengths. And they’re priced decently too

https://www.kjmagnetics.com/


#14

Did no one think about or try out finishing nails?

I haven’t tried it myself, but I was working on a cheese board this morning that I now realize I could have use them instead of using all my magnets to try and keep it in place.

I wonder if we have any finishing nails in the garage…


#15

I use this method when magnets won’t do.

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#16

Cotter pins - brilliant - I must see what’s in the workshop here, and start experimenting. Must have plenty of warped plywood in UK with the current weather pattern !

:upside_down_face:


#17

You can make a quick pin bed using small neodymium magnets (like the 3-4mm ones) and brads or small nails. drop the magnets on the base where you want your pins and then place a nail on each pointy side up. Easy to throw a dozen on there quickly, no need for precises placement and then when you’re done, pull off the nails and use a bigger magnet to suck up all the little ones from the bed.


#18

Now thinking of neo magnat on the base holding a machine screw, up through the honeycomb, with a wing hut bearing down onto a wooden hold down piece just clamping the edge.

:upside_down_face:


#19

Have magnets that you really like? Where do you get them? I have some rare earth ones that are small enough, they aren’t too much of a paint to get them to release, but still have a LOT of holding power. I might use those.


#20

Scroll back, I listed my sources.