Thread: 850mm Shop Made drum sander

I'm going to be using a scissor jack as the height control for the workpiece table; the one that I've acquired has a reasonably fine thread so should be ok for the degree of accuracy required. As the standard winding handle isn't ideal, I've fabricated a winding rod and handle that will allow the elevator control to come throught the front of the fully encased sander frame.

The workpiece table will ride on four vertically mounted static chrome steel (for smoothness) rails, with the table having corner holes that are a good (but not too tight) fit for these rails. This will help ensure lateral/transverse stability and aid in making the table remain parallel to the frame's base.

I will also be making a height locking mechanism so that any vibration won't alter the workpiece table height during operation.

For a power supply, I've acquired a new 3HP single phase motor. Hopefully this will be enough for an 850 long drum.

Yet to be made is the outer frame, the dust hood with dust extraction (2 100mm ports I'm thinking) plus the motor mount. This latter will use a cantilever base plate so using the motor's weight as a belt tensioner. If required, I'll add some springs and /or a tensioner pulley on a spring-loaded arm.

I'm also thinking of making some swivelling (or perhaps demountable) in- and out-feed tables.

The idea of a powered feed mechanism is appealing, but I've no idea where to lay my hands on a suitable gearbox & motor; then there's the matter of making the feed rollers adequately aligned, etc. Hmmm, maybe pushsticks will do until I can think up something better.

Pics show the jack, winding mechanism, a spacer block with hand cut groove for the woodruff key (only really used to act as a spacer between the drum and the pulley). Note the "raspberry jam" camaflauge effect caused by one dipstick having finger misplaced on the far side of the spacer block when chiselling the groove

Now: a question for those that have persevered thus far and who have made one of these beasts: I've covered (saturated!) the fibreboard drum laminate sections with epoxy to both stabilise and make more rigid the drum. Should I glue on some rubber spiral-wound strips to act as a cushion under the sanding belt? BTW, the drum, after the application of the epoxy, was turned slowly for a couple of hours to ensure an even distribution - that's the reason for the wooden pully (made on the drill press from Jarrah and a set of rasps and files). It will then be finish ground in situ using a sanding plate - a sort of inversion of workpiece to sanding medium...

All up, I estimate that this tool will cost around $400 - $167 for the motor (incl freight), $140 for the axle and bearings, $34 for the jack, and the balance for pulleys, minor hardware, etc.

I'll be grain filling then painting the outer surfaces - any sugestions as to colour - NOT ORANGE !

Steve, well done! You could paint it Record Blue like your vice or Dawn Red. As long as it is not that 'orrible Orange!!!!!

Well done Steve, it is looking good.

Some observations:

A power feed would be wonderfull and a necessity if you use it all the time. However the mechanics of it is rather difficult so I'm happy to use pushblocks.

I didn't use any epoxy on the drum, don't think it is necessary as the final sanding will make it as smooth as a baby's bottom.

I wouldn't glue on some rubber spiral-wound strips to act as a cushion under the sanding belt as this would allow some unevenness in your sanding.

As to the colour scheme I used red, white and black. Would have preferred red, white and blue with a touch of orange but I didn't have blue paint.


Peter.

Steve

I am surprised that you are asking for suggestions for colour scheme. I thought every Victorian given a chance to choose colours for anything would choose the colours of his or her footy team!
Problem solved - and if you don't have an AFL team, try green and gold for the Socceroos!!

Cheers

Jeremy

Has anyone here made up a power feed mechanism? If so, what sort of motor/gearbox and/or belt drive system was used? Also, how was the drive transferred to the workpiece - by friction rollers, a conveyor belt arrangement?

Today I looked at a 12v DC motor with attached gearbox: it has ample torque (20NM) and had an output speed of 160RPM (about twice what I need, but easily dealt with). The downside was, being 12v, and with a stall loading of 17A, the complication and cost of setting up a suitable power supply ($220 for that alone) seemed to be just too complicated. I like simple...

Any ideas where I can lay my mitts on a c200 ~ 300W 240v AC motor with an attached gearbox?

I'm wondering if the motor and conveyor system from a printer or copier could be adapted (not the stepper motor kind)?

I'm definitely not paying $750 for a 150w feeder unit like those sold by H&F, C-T, et al...

Any ideas?

Understand you have an aversion to orange. That's cool
Quite a good colour instead is Telecom Gold

On a more serious note, power feed motor - what wattage is a sewing machine motor?

Does the sanding drum require any cushioning, or does that prevent the machine from functioning properly?

Was just thinking about a belt for your feeder unit- would using a wide piece from a belt sander work? Not taking about the handheld powertools here. Ohh- hang on, how much torque would a cheap belt sander have, if you voltage regulated it? What about a cheap drill and a pulley system to gear it down? $15 for a 240V motor (Probably no torque though, but when geared down, may be powerful enough).

As you can see, I'd definitely go the conveyor belt route.

Steve, great effort so far And you should go all out and get the feed motorised. It would be a right PITA to use a primative push stick. A few years ago i met a bloke who made a huge spit to take a whole cow and he used a small motor from a Kodac film processor and it had HUGE tourqe which is what you will need. If you dont go the motorised way, have a look at the great hand powered feed on the sander in the current Shopnotes.

Hi Steve,
Its looking really good, and I for one can't wait to hear how it runs. How will the abrasive be held on the roller?
With your power feed, is there any sense in looking at a hand cranked system? I know that sounds funny, but with a decent crank handle, gearing and chains, you could acheive the torque and control the feed speed to whatever is required. Anyway, just a thought, good luck with it!

Cheers,

Try a windscreen motor for the drive. you can pick one up from pick apart or someone like them

Originally Posted by Andy Mac

How will the abrasive be held on the roller?

Cheers,

The cloth backed abrasive will be spiral wound, and held on at the drum's ends with large Jubilee (aka hose) clamps.

I visited Clark Rubber today and obtained some +/- 3mm thick flat rubber sheet - this I'll glue with contact adhesive to the drum; not spiral wound but just around. This will a) provide a degree of cushioning and b) a non-slip surface for the abrasive. If one feels the base of, say, a ROS, it has some give - it's this that I'd like to emulate.

Niall: W/screen motors are either 12v or 24v DC - and I'd rather avoid the issue of acquiring and installing a power supply of the required capacity.

Originally Posted by Lignum

If you dont go the motorised way, have a look at the great hand powered feed on the sander in the current Shopnotes.

I think I have the that edition of Shopnotes, but can't find it at the mo

I've found a small 135w 240v A/C motor that, with a bit of conjuring, might do the trick It came from an old Ryobi buffing/car-polishing thingy that had a crack in it's plastic moulding. Pulled it all apart and there's a nice little motor that doesn't seem to rev all that much; quite how much I'm not sure - will have to try some empirical measurements or see if I can pursuade a friendly local mechanic (???) to measure it with his strobe timing gun.

Thinking some more about the conveyor belt approach, whilst probably the best would need a series of absolutely level rollers spaced pretty closely together so that the feed stock doesn't behave like a surfboard in a swell

Sooo, I'm tending towards a pair of rubber coated spindles parallel to the main drum, one in front and one behind. Each will be supported by a bearing/carrier, and located vertically in a spring enclosed shaft at each end such that these spindles at rest are just below the drum, but are free, albeit under pressure, to rise as the feed-stock progresses through.

This is getting to be a bit more complicated that I originally intended, but it's fun

I picked up some keyed pulleys (1 x 19mm bore & 1 x 25mm bore), both to take a type 'B' belt, plus some 19mm aluminium solid bar and corresponding bearings/carriers today.

I also collected the 3hp Intem motor from A/P today (watching the poor old duck behind the counter trying to pick the thing up made me offer to come around and help, but that's not allowed!, so I had to watch as she huffed and puffed - ach, shame!).

Thankfully the pulleys fit both the motor and drum's keyed shafts exactly.

I've gone for equal sized pulleys for motor & drum initially, partly because that was about all the supplier had ( ), partly because I've noted comments here about shop-built drum sander's rotational speed (some have been saying c5000rpm), whereas a commercially available wide drum unit (eg Jet) has its drum running at 1,600 ~ 1,700 rpm depending on the model. As the motor is rated at 2830rpm, I'll try it (from a distance :eek: ), and increase the drum pulley's size if needed.

BTW: Am I correct in assuming that the drum should rotate clockwise when viewed from the right (i.e. bottom surface rotating towards the incoming feed-stock)?

Next up will be to fabricate the main motor's mounting plate with a swivel point along one edge (so that the weight of the motor will provide the required belt tension) I hope...

I was thinking that I'd have to get a relatively hefty switch for the main motor and a smaller one for the feed motor, but as it turns out both have a 10A plug on their cords, so I'll be cheap and just get a small switched patch-board

At the weekend, I'll start with the main frame, and, hopefully, will have some more suggestions as to the feed mechanism.

Originally Posted by Auld Bassoon

This is getting to be a bit more complicated that I originally intended

:eek: :eek:

Originally Posted by Lignum

:eek: :eek:

I know, I know I keep getting good simple ideas, then burgerise them to hades and gone by adding a bit of this and a bit of that...