Sachakins
The most wasted of days is one without woodwork
Thats a great suggestion, thanks
Drum Sander diy pre build question.
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Thats a great suggestion, thanks
Orraloon
Established Member
The flat master gets a side flat like a jointer does but when you do the other side the piece it is unlikely to be of even thickness. Thats why the overhead drum machine acting like a thicknesser is better and you see more of those around.
Regards
John
Regards
John
sometimewoodworker
Established Member
What you say is correct in the point of the flatmaster or base drum sander acting in a different way to an overhead sander.
You are wrong that it will not usually get items of an even thickness, you just need to use it in a different way to an overhead sander.
They are different tools with different uses. The reason for the majority of drum sanders being overhead has nothing to do with the overhead being better, it is because there are many more companies selling them.
Your analogy is similar to saying that a plainer is less good than a thicknesser. It isn’t it’s a different tool though many jobs can be done by both, although in that case they both use the same cutter bar setup.
FWIW I have used my V drum sander often, I haven’t had a desperate need to parallel sand any items. If I had a regular drum sander I might have a use for it occasionally.
YMMV you may well have a different use case to mine.
I don't understand the drum being under the work at all.
When the drum is above the work, the work is being referenced off what is under it, which is a constant.
If the drum is under the work, then the work is being referenced from nothing at all. It's not being referenced from the air above it, and, unless the outfeed can be altered in height, like a planer, it's going to be rocking about on top of the drum.
I mean, in practice it might be passable, but the logic of it certainly does not work in my head.
I'm following this as I'm strongly considering a build myself at present.
I figure a fixed overhead roller and a solid, non conveyor, tilting bed under it.
The tilt would be adjustable and hence alter the gap between the bed and the roller.
I'm not set on this idea, but it seemed the best plan I could work out.
When the drum is above the work, the work is being referenced off what is under it, which is a constant.
If the drum is under the work, then the work is being referenced from nothing at all. It's not being referenced from the air above it, and, unless the outfeed can be altered in height, like a planer, it's going to be rocking about on top of the drum.
I mean, in practice it might be passable, but the logic of it certainly does not work in my head.
I'm following this as I'm strongly considering a build myself at present.
I figure a fixed overhead roller and a solid, non conveyor, tilting bed under it.
The tilt would be adjustable and hence alter the gap between the bed and the roller.
I'm not set on this idea, but it seemed the best plan I could work out.
I tried a drum sander build twice. First with a PVC pipe drum, and then with MDF discs. Could not get the PVC true enough, so went for the MDF, but with a 20mm threaded shaft (as many videos describe, the weight of the MDF caused vibrations in the cylinder. So I bought a used Jet drum sander and it works like a charm. Just saying...
If I build one, I'll either use a roller off a scrapped conveyor belt system, or get one made up.
I would not be making the roller myself without a metal lathe.
I saw a little jet sander sell on eBay for £300 a couple of weeks ago. I'd have happily paid that, but it was miles away.
There's one on FB market place, local to me, for £600 (same model) which is more than I want to spend by quite a lot.
I would not be making the roller myself without a metal lathe.
I saw a little jet sander sell on eBay for £300 a couple of weeks ago. I'd have happily paid that, but it was miles away.
There's one on FB market place, local to me, for £600 (same model) which is more than I want to spend by quite a lot.
Inspector
Nyuck, Nyuck, Nyuck!
The under drum sanders are meant to smooth work already thicknessed in a thicknesser. Think of it for taking out the tear out and cutter knick lines and getting a smooth surface ready for the last grit or two of hand sanding before finishing. Some people do use them to flatten a board when they don't have a surfacer or the wood is too wide for it.
Pete
Have a look at my thicknesser sander in Workshop/Shopmade Tools thread "More a shop made machine " it could be made larger for full size work but might need anti kick back and a feeder
Then you you can tell SWMBO you are doing your bit fot the planet by recycling and cut lecky bill by pinching the motor out of her Tumble drier lol 
For me, the appeal of a drum sander is to take any small movement out of a job right at the end of the process.
I have a thickenesser, so I'd never want to proportion a job on a drum sander, but just to take off fractions of a mm, if need be, just to take out any movement that's occured after machining.
So, for me, an under work drum would be useless.
If I just want somthing smooth, I can use a DA sander.
I appreciate what you are saying but it still seems like madness to me! : )
Sachakins
The most wasted of days is one without woodwork
Been there, done that, ìts on my 12" **** sander...Then you you can tell SWMBO you are doing your bit fot the planet by recycling and cut lecky bill by pinching the motor out of her Tumble drier lol
sometimewoodworker
Established Member
You really need to watch the many videos explaining and demonstrating the use.
NO the work is not rocking about on the drum. Yes the work is referenced. It is referenced from the table. No there is no need for the table to have different heights.Yes you miss understand the principle. At rest the sand paper will not contact the workpiece it sits under the level of the table
If you have a need for a thicknesser you will be badly advised to buy a plainer.
If you need a plainer you will be badly advised to buy a thicknesser. The analogy is extremely close
The same is true for drum sanders. If you need to constantly use a drum sander to make many items exactly the same thickness (they must already be flat) then an under table sander is not the one for you.
If you have a need to flatten, remove glue, sand off finishes, not have sanding dust in the air/on the workpiece without dust extraction etc then an overhead drum sander is a bad choice.
The under table drum sander doesn’t get hot so it will not melt glue and finish in the way an overhead drum does, and must do as the paper is squeezed between the drum and workpiece so heats up, the under table sander with the paper held on by Velcro floats the paper slightly off the drum so the only heat is from abrasion and if the paper is cutting that is minimal.
that is exactly and 100% wrong the underwork drum is the perfect tool for that, with 220 grit and finer you can get a cut of 2 thousandths of an inch ( 0.0508mm ) or less
Most important question is exactly what do you want to do with the sander? If thicknessing then that’s the correct choice. If flattening it is not, the best option.
A homemade option
there are many people who would be better suited to an under table drum version who have bought an overhead version for the simple reason that there is little information available, I only know 1 company that sells them.
they are certainly not the best option for everyone and I don’t suggest they are.
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Sachakins
The most wasted of days is one without woodwork
Thanks for your time and effort in these comments and I think I need to rethink my ideas and define more clearly.
To clarify my needs are three fold (i think)
1) Create flat ring face and then make parallel faces (even thickness) for 15mm plus ring thickness.
2) Create very thin rings on bandsaw from thick segmented rings, then sand òut cut marks.
3) Clean up the faces of long thin stock, some only 0.5mm thick, that i cut on bandsaw, again for glue up patterned laminated timber for making dizzy bowl designs in turning and for feature ring designs on segmented work.
For the segmented rings, initially the timber is put through my planer/thicknesser. This dimensions my timber.
After cutting and then glueing up the rings, this results in some inaccuracies, so I then need to first flatten one side, I then need to make the faces parallel. If not parallel, this ruins the final pattern for turning.
The rings can vary in thickness from 45mm, and some down to 0.75 mm, and because of their construction, its risky putting them through my planer/thicknesser again as the grain orientation varies, risking chipping. Also anything under 4mm is a no go on my machine, unless I make a sled for thin stock. Also limited width of 205mm
I have just got new bandsaw blade from Tuffsaws, and this has improved cut on thin stock greatly, so I would only need a light pass.
I have made a diy version of a Luthiers Sanding Station for my bobbin sander and this is OK so far, but max width of board only about 95 mm. So no good for the rings.
This is the original Luthiers Friend sanding Station, used with a pillar drill.
Thanks to everyone, I wìll try and sketch out ideas in couple of weeks.
For examples of dizzy patterns, segmented feature ring design i recommend looking at the Accu-slice youtube and website from John Manura, his jigs and tools are amazing, but not affordable to me, so i made my diy thin slice bandsaw jig for my Kitty 513 loosely based on his accu-sled and accu-slice designs.! Which gives repeatable thin cuts within 2 or 3 thousands variance.
sometimewoodworker
Established Member
here is an exact example.
regrettably you probably need both kinds of sander and no they can’t successfully be a single machine. The compromise in attach for the paper doesn’t allow that.
the under table drum will give an excellent flat surface and take off the glue, but if you must have parallel then an above table version may be needed to finish the pieces. It, with a backer board, will deal with the long stock, though that may depend on exactly what you mean by long.
If I were in your place I would get/build an under table version and see if you can use that as the majority of your work is best for that version. Then if you find a need for more parallel consider an overhead later.
As promised here are pictures of my unit in working condition
and here is the parking position of the motor, note the high tech piece of silk string
I'd be interested in a drum sander for finishing end grain cutting boards after flattening with a router sled. If I will be doing a lot more of them that or a belt sander will be required...
This one always looked easy to build to me:
This one always looked easy to build to me:
Trainee neophyte
Established Member
Stumpy Nubs combined both types of sander by having the v sander on top and thicknesser underneath a single drum. I have no idea what compromises this would bring in, but it's a completely over-the-top build, so why not try it?
TheTiddles
Established Member
I think you want a standard drum sander. Which you could buy, or make. I can’t see how the planer-type drums will work for you at all (in fact I can’t see how they are that great for anything, which might explain why you don’t see them very much).
You could make one that fits your lathe and have one less machine, but your lathe is bolted down. You’ve got a lot of work to do to make one if you don’t want to spend a lot on buying one. My assumption analysis indicates that maybe your effort should go into making a lathe based one and sort out moving your lathe, such as a rolling stand, as cheaper and faster than building a standalone machine.
You could make one that fits your lathe and have one less machine, but your lathe is bolted down. You’ve got a lot of work to do to make one if you don’t want to spend a lot on buying one. My assumption analysis indicates that maybe your effort should go into making a lathe based one and sort out moving your lathe, such as a rolling stand, as cheaper and faster than building a standalone machine.
Sachakins
The most wasted of days is one without woodwork
I think I'll make a simple under drum (sand flee type) this will allow me to flatten large rings, then I could face off the other side on the lathe if they're not parallel. I the mean time I can still use my Luthiers Friend type jig for my thin stock, as although I say there long, to me 36" is long, and it does clean up boards up to 75mm thick and down to 0.75mm. And currently I don't go over 95mm with them, but going wider in near future I think.
I already have a spare motor and nvr switch, and two pillow block bearings (but weird 17mm bore) and enough ply bits to make do,
As the roller will be smaller and velcro fitting, I'll try MDF disks, or a pvc tube with epoxy or cement core for rigidity on a steel shaft with 17mm ends?
I already have a spare motor and nvr switch, and two pillow block bearings (but weird 17mm bore) and enough ply bits to make do,
As the roller will be smaller and velcro fitting, I'll try MDF disks, or a pvc tube with epoxy or cement core for rigidity on a steel shaft with 17mm ends?
Inspector
Nyuck, Nyuck, Nyuck!
I think your shafting is too small. My 22"/560mm drum (5"/125mm diameter) drum sander has a 1"/25mm shaft. It is an overhead type.
Pete
Pete
