Thickness Sander - First

[snow]

A while ago in the "General" forum I said that I would post photos of a Thickness Sander the my mate Al and I made.

The time has arrived. The details are as follows:

The frame is made of 30mm square tube, 2mm wall. The drum is made from 100mm heavy guage pipe spinning on a 25mm shaft (full length) supported by roller bearings and saddles. The table top is a part of an old laminex bench top (40mm thick). The winding mechanism is a modified car jack from the wreckers.

This machine is very "agricultural" in its operation. The timber is fed manually, and for larger panels it is really a two person operation. One on the infeed the other on the outfeed.

At the moment we are experimenting using different grade paper, and are waiting for some cloth backed stuff to arrive. (Opinions welcome).

Al had the motor already which was a real bonus. The total cost of the project was just under $200.

After running some test pieces throught the sander, we put a veneered desk top through (silver wattle). It came up a treat. Flat and even. Hours of time saved. With a full sanding width of 1000mm I'm looking for some larger projects to undertake.

Comments please

Snow

[ozwinner]

Bloody brilliant!!!!!!!!!!!!!
I am thinking of makeing one for myself, but was concerned about the rise and fall, did you just fix one end with a pivot?
I thought about the car jack method, but was concerned about keeping it all pararel.
But if one end is fixed that solves that problem.
How did you manage to get the shaft running true?
Have you thought about putting a variable speed control onto the motor?
I suppose the thickest timber that will be fed through will be about 100mm, so the table could be level at 100mm, and rise up for thinner thicknesses, that way gravity will assist with the thinner bits.
What about a springy infeed roller to keep the stuff flat on the table?
Sure beats the $2000, for a Tiawanese job.

Thanks guys, I love it, Allan :) :) :) :) :) :) :)

[ozwinner]

Oh yeah one more thing, how is the paper kept on?

Allan

[snow]

Allan,

Answers to your questions;

The paper is held at the end with tape and wound onto the drum against the rotation and secured at the other end with more tape, this way the paper actually binds its self to the drum.

The table is pivoted on two very solid hinges.

There is an angle iron frame under the table(hinges attached to it) this keeps the table true. The jack pivots on the angle iron frame. The whole lot is tensioned with two very beefy springs on either side.

The roller and shaft would normally have been a challange, but Al is a Fitter Machinist by trade with access to a full engineering workshop. Needless to say, this was not really much of a problem in the end.

I like the idea about the softer roller to help maintain pressure on the table........MMMMMMMMM I'll have to think about it.

Snow

[ozwinner]

Just thinking more on the drum sander.
The infeed roller could be spring tensioned, and powered by the other roller via a belt..

Cheers, Allan

[Sturdee]

Snow,

I am speechless, it looks fantastic.

I have had the idea of making a drum sander for a while now and have been collecting a number of plans on how to make them, but they are only 13" sizes. I will have to revise my thinking to make it larger. On this size you definitely need an infeed roller powered by belt from the main roller.

Ozwinner if you want copies of the plans I have send me a PM with your contact details.

Peter.

[ozwinner]

Is it still possible to twist a belt these days to reverse the drive direction?
The feed roller drive would have to go the in opposite direction.
What other way is there to do it?

Allan

[glenn k]

A few years ago I paid $12US for a plan to make one. Very similar except they made there roller from wood glued onto a steel shaft then started it up and cut it straight with a gouge. They used allthread with a wheel built on a nut for the height.
The paper they recomended was wound on to a velco drum I have never seen this strip felco paper in Australia. Is it available?

[Al Burdon]

Hi Guys,
I'm the other half of the team that built the sander.
The drum was machined true and welded with as little heat as possible to prevent warping. Our first try was .5 kg out of balance which was impressive when spinning. The final drum was so close that without using vibration analysis gear we we unable to find a balance problem. The pullies are a little dinged and cause a mild shudder on acceleration and deceleration but hey at the price you can't bitch.
As Snow said the paper is wound against rotation and duck taped at each end and I think velcro backed or gluing isn't needed. As for an automatic feed we may consider it but it isnt really necessary. For those not having access to a metal lathe we considered the approach from the Moritz design which was threaded rod with wooden disks which were trued in the finished machine. The motor is a 1HP motor from SHMBO's grandfather workshop approx 1930's to 40's vintage. Motor speed is 1400 RPM pullies are approx 2:3 step up so output is approx 1900 -2100 rpm.
The dust collection ,which is definately required is handled by a home built cyclone using a taiwanese 2hp dust extractor.

I'm a bit worried when Snow says I'll think about it it generally means work as I had toyed with the sander idea for a while but he kept the pressure up to finally do it.

[Eastie]

One comment in particular – you’ve made a guard for the pulley system – how about one for the main roller and infeed area to help prevent fingers, clothing, etc from going in? As it is there is a pinch point between the roller and square section at the infeed.

I know, I know – guards are no substitute for brains, but like brains you just never know when they may come in handly, so to speak.

I recon the design is a winner.

[Dan]

I think the dust hood would function as a guard for the main roller, looks like Snow or Al has removed it for a clearer photo.

Dan

[MrFixIt]

Originally posted by ozwinner
Is it still possible to twist a belt these days to reverse the drive direction?
The feed roller drive would have to go the in opposite direction.
What other way is there to do it?

You could contemplate a visit to your local tip/recycling plant and look for a powered walking exersize machine - the type with the powered belt/tread.

The motor may not be powerful enough for a 1000mm sander, however the mechanism may be able to be adapted to a larger motor?

Regards

Peter

[MrFixIt]

Hi Al & Snow (et al)

What a great sander!!!!!!!!!!!!

Just had another thought (for the Mk II version). What if you had a second drum with a finer grit of sandpaper, driven by another motor in the opposite direction to the current drum.

With an appropriate "tensioning" mechanism you could adjust the tension of the finer drum to allow the coarser drum to drive the timber through. The speed of the motors would not really matter as the drive would be dependant on the tension of one roller compared to the tension on the other.

If the drums rotated towards each other (at the bottom) the first roller would pull the timber in (hmmm? maybe not the best direction?) but it would help with the dust extraction.

There would be a limitation as to the shortest length of timber on which such a sander would work, however if you could use the drums alternately ie drum 1 down/drum 2 up then drum 2 down/drum 1 up it would be a versatile unit.

Regards

Peter

[Al Burdon]

The Square tube and dust cover over the drum prevent inadvertant finger sanding and as with all tools of this nature we use a push stick (1M X 250mm X 6mm MDF). Good idea about the 2nd roller with finer grit but using the 60 grit it only takes 30 mins or so with a random orbital or finishing sander to go up the grades for a good finish. The feed mechanism is something we will think about but we would much rather not waste the power of the motor. The two methods of power feed are:
1. The moving belt . This has alot of moving parts would interfere with our height setting mechanism so would probably require a redesign and to much expense.
2. The infeed and outfeed rollers. Both require to rotate in the opposite direction to the sanding roller so an 2 X idler gears are needed to reverse rotation (the twisted belt idea would require an extension to the end of the main drum or idler pulleys to achieve the same) all these would bleed too much power from the drum to drive the feed mechanism. Also the table moves on a pivot to achieve thickness control and this would require a floating mechanism for the feed rollers to work.

To achieve a satisfactory feed mechanism would require the table to move up and down parallel to the whole feed and sanding mechanism or for the mechanism to move up or down in relationship to the table.

We considered this approach but to keep to Snow,s construction budget of @#*&% all the design we built seemed to be the most workable solution. But I do have my feellers out for a separate powered feed.

[Ian007]

a mate of mine put me onto your sander because he wanted to make one
so i had a look, great stuff. and now i am making one 2. I went to the local used machinery place and paid $40 for a steel roller with bearings and another $10 for a pulley to suit
the roller would appear to be balanced as it came out of some machine it is 915mm x 115mm dia size of roller only ill let you know how it ends up
cheers Ian

[Al Burdon]

Sounds like you are on a winner if you need any help just drop a line

Al