Friday, 4 September 2015

Homemade sanding mandrels...

If you're into making stuff from wood (or other materials) you'll know that some times the price of equipment can be quite high, so why buy it if you can make it for free ? (well almost free)

I'm often in need of small sanding tools, specifically something to attach small sanding pads to, and although you can get them quite cheaply when you have to start buying three or four the the price can add up, so I made my own.

Here they are -

Nothing special, by they work well.

There are benefits to making your own tools, the first is obviously the price, you can more often than not make things quite cheaply, or as in the case of these mandrels free from stuff you have lying about, the other benefit is that you can custom make things to suit your needs.

These where easy to make and are basically a bit of plywood with some rubber stuck to it, with some threaded bar to form a shaft for use in drills, or in my case they get used with a flexible drive shaft for sanding stuff I've made on the lathe.

Ingredients - 

Bit of threaded bar - 

check.

Some 'T' nuts and normal nuts (and a few washers) -

check.

Some plywood to cut discs from - 

Already cut.

Some rubber or dense foam - 

Two sorts here, neoprene and the stuff they repair shoe soles with.

And some Velcro (if you use tape use the hook part) - 

Doesn't have to be sticky.

To cut the plywood discs I used a hole saw, this was handy as the hole through the middle is just the right size for the threaded bar, it's also a good fit for the 'T' nuts, I salvaged the 'T' nuts from an old chair, but you can buy them quite cheaply.

Once the 'T' nuts are fitted into the wood discs (which only takes a couple of taps with a hammer) you can cut the threaded bar to what ever length you want, I cut mine to about 45mm, then you can screw it into the 'T' nuts, I also used a bit of thread lock on the end of the threaded bar, but you don't have to.

Bar and 'T' nuts - 

Now for a bit of thread lock.

Thread lock applied - 

It's not essential.

The thread lock is like a glue which helps stop things coming undone, the next step is to add a few nuts on the other side of the wood disc, so what you're trying to do is clamp the wood between the 'T' nut on one side and the normal nust on the other.

Make sure to get the threaded bar as flush with the 'T' nut as you can, you can also use nyloc nuts on the other side of the mandrel, they are the nuts that have a little bit of plastic (Nylon) at one end.

Nuts added almost done - 

A washer will help stop the nuts digging into the wood.

Now for a bit of tidying up - 

Just a quick sand to tidy the wood up a bit.

I put the mandrel into my post drill, just to get the rough edges of the ply, the main shaping and finishing was done on my lathe, but there's no reason you couldn't shape the mandrels in a post drill, or a hand held drill in a vice.

I also sanded the side with the 'T' nuts, just to make sure there were no sharp bits, and to make things nice and flush.

Sanded nice and flush - 

Ready for foam type stuff.

Onto the foam / rubber, I've made a few of these now with different materials, some with a fairly soft neoprene which gives me a bit more flexibility when it comes to sanding curved stuff, the more ridged rubber is great for flat stuff.

All I've done is cut a rough square of the foam (slightly bigger than the wood) and using impact adhesive stuck it to the wood part of the mandrel, then all you have to do is wait for it to set.

Waiting for glue to set - 

Leave it for as long as possible to make sure the bond is good.

When the glue was set I trimmed up the foam and then put the mandrel on may lathe so I could shape the wood and the foam with some sand paper, then all that needed to be done was to add the Velcro for the sanding disc to stick to, again I cut a little more than I needed and then trimmed it up once the glue had set, even though the Velcro I used had adhesive on it I still used a bit of glue to make sure they don't fall apart.

Waiting for glue to set again - 

It's easy enough to remove the extra bits of glue.

Finished, I've made some in slightly different shapes, and I plan to make more to suit my needs, they work well and they hold the small sanding discs quite firmly, which is good, and as I have more than one I can keep different grades of sand paper on each one, which makes changing grades quicker as I can just swap out the whole thing.

All done - 

Ready for action.

Thanks for reading.


Allotment update (part 2)

Welcome back, this is part two of my current allotment adventures, I had to break it into two posts as it seems I've done quite bit. ...