flexible mounts for sanding table

[Glot]

I am trying to come up with some idea for mounting a 300mm x 300mm platform to use as a large orbital sander ( face up). My problem is I want it to move 1 to 2 cm at it's longest travel. It will be more elliptical than round movement. Will run at about 3 to 4 cycles per second. Only rubber mounts I can source won't handle the amount of movement. Any and all suggestions welcomed. I have considered suspending it. Using sets of ball sliders mounted at 90 deg to each other. Compression springs seems the more obvious but how.

[Frank S]

Why not try something like this you could use extension springs to hold the table down or centered on the ball rollers you movement would be limited only to your imagination.

They are called ball bearing rollers

[Glot]

Interesting thought. Thanks Frank. I will check it out more.

[Glot]

I am going to experiment with some short lengths of silicone rubber round bar. Will have a cup top and bottom out of pipe then force the ends in to them. Drive will be from a cheap variable speed jigsaw. This will give me a recpricating table to clamp sandpaper to. The idea is, if using a disc sander, you only use about 65% of a sheet. This will use close to 100%

[suther51]

Giant upside down square sheet sander? Mmmmm... I like the sounds of that. Sounds like you are looking to make rubber torsion(?) Mounts? What about flexible (rubber) fuel line pieces clamped to opposing pins. The distance or space between the pins may be critical but would give a simple flexible "joint" for movement in two directions. Some other type of hose may work better, something like the silicone tubing used in coffee makers to join the plastic pipe to the aluminum pipe in the burner. There is an answer out there somewhere

[ranald]

You could try what i did for vibrating concrete in small head-stone moulds. two platforms with a 2 " by 2" diameter spring mounted near each corner. Of course you dont want to use flat steel plate for construction and a whipper snipper just above idle to give the vibration. A later improved (no smoke) version saw one spring moved a bit and a steel bar set in its place and fixed to one surface. a small electric motor (like a washing machine) with its shaft ovaled ran touching the bar gave good vibration.

As you have sourced rubber feet you could try 2 feet with joining tubing between nearer the centre but still supporting the sander platform.

[Glot]

I like that idea too.

[Glot]

Version #1. Sort of works but main issue is the travel of the saw is too much. The overall action is too violent. I was going to add an image but looks like this stupid site requires some outdated format or something.

[Glot]

Version #1. Sort of works but main issue is the travel of the saw is too much. The overall action is too violent.

[Frank S]

Now that I see what you were making. many of the ideas for movement control that were published would have worked equally well.
As for being violent there are 2 ways to tone that down one being mass the other being variable speed
many saber saws have a high and low speed others are variable I have one that has both
you could use a link bar between the saw and the plate with a pivot being closer to the plate than the saw something like 1.5 to 1 or what ever it took to reduce the total movement

Or you might try attaching a stiff extension spring to the plate then attach the other end to the saber saw this might dampen the stroke and the violence.
If that is not enough then attach a second spring to the plate where the first spring is connected and attach the other end to the base mount
I built a small gold sluice several years back using a similar spring set up