Drill Press thickness sander

[Alastair]

Hi All,

I am busy converting a surplus "hobby" benchtop drill press into a simple thickness sander. Initial prototype seems promising.

I will post some pics when finished. If it works well, and there is interest, I will post details on construction.

Regards

[wheelinround]

Sounds interesting Alastair mind if I pull up a pew

[walcen]

Yeh we love pics, and tool conversions, and stuff :2tsup::2tsup:.

[Alastair]

Just ran some resawn SO on the (un)-finished prototype.

Keynote is softly, softly...., but not unhappy with the result.

Took a piece of badly washboarded 12" x 5" silky oak, I had resawn while setting up bandsaw.
It took about 10 passes to get rid of it. cf 3 passes on a jointer. Then I took it down on both sides to 2mm

Finish is acceptable, with a touch of sanding marks. I expect this will improve once I true up the drum on the drillpress. Certainly there is nothing which would not come out with a card scraper.

I miked the piece on 4 corners, and middle of long sides, and variation was from 1.95mm - 2.05mm, so certainly OK for sides and bindings. Unfortunately the width capcity won't handle half a back or SB,

I may be able to remake the drum and get an inch more width, but we'll see whether it's worth it.

Taken some pics, and will post next week.

regards

[Alastair]

As I am meddling with guitars, I started looking at abrasive planing as a means to achieve accurate dimensions for soundboard, back and side plates.
I was less concerned with the final thinning of the joined top and back. My planing skills are adequate for these. In particular, I was more concerned with the sides and bindings, where the need to clamp at an end “forced” you to at least plane against the grain at some point. Added to this, accurate thickness, and absence of tearout was particularly important when it came to bending. In addition, I wished to be able to do the initial thinning of the bookmatched resawn halfs of the soundboard and back, before joining
I looked at various plans for home-built units, but the combination of only occasional use, and convenience, meant I was reluctant to go for either a dedicated homemade unit, or a jig to run on my wood lathe.
I DID however have a surplus hobby Ryobi benchtop drill press. (I had inherited a second one when I moved into my house). Given my thoughts above, it seemed possible that I might be able to get enough width (height) capacity, to meet my modest needs.
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In order to avoid axial loading on the chuck bearing and quill, it was necessary to run a bearing to support the free end. I was able to find one with 19mm OD, and 7mm ID. This allowed me to drill out the existing hole in the centre of the drill press table, using a ¾ “ drill in the press. Neat enough fit with the 19mm bearing.
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Shaft was 5/16 “ threaded rod from BB, (effectively 8mm). This I gripped in my lathe chuck, and filed the threads down to give a snug fit into the bearing. There was still enough “meat” on the threads to run a nut up to secure the bearing in place.
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The drum was made up of sections of 45mm radiata. These were cut off square, and centre drilled 7.5mm on the press. That left them to be “threaded “onto the shaft. As each subsequent section came close to the previous, the last bit of thread was coated with epoxy, the face with wood glue, and then snugged up tight; repeated for the rest of the sections.
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This I then set up on the wood lathe, and turned to a smooth cylinder, gripping the shaft in a drill chuck in the headstock, and supporting the bearing in a dummy chuck in the tailstock. I was not too anal with the final dimensions, as I intended to finish it on the rig. In the absence of a lathe, this could be done in a router jig.
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To install, the pedestal table is swung out of the way, the shaft gripped in the drill press chuck, and the table swung back into position, lifted to engage the bearing in the 19mm hole, and clamped into position. Switched on, it seemed to run well, and had surprising torque, (which had been my principal concern with the project).
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I have kept the fence simple. Just knocked up out of scrap 16mm melamine, and braced to a (reasonably) accurate 90 deg. A cut out is run on the bandsaw to accommodate the sanding drum, and it is simply clamped to the pedestal table, and adjusted by tapping with my plane adjusting mallet. I reckon this will be good enough for me, but if you are detail minded, I’m sure you could rig up a screw adjustment, back to the pedestal column.
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At this point, I cut sandpaper to shape, and wrapped the rough drum, securing at the fine ends with staples. A trial run on some left over resawn Silky Oak was encouraging enough to carry on and complete, although sanding dust flew everywhere!
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Dust extraction is a must. I bought a guttering “tee” for this. “Split” along the back on the table saw to allow the drum to protrude, and an angle bracket riveted on. A nice big RE magnet served to secure it to the table. it was coupled up to the shop vac. It gave reasonable dust control, (and certainly better than without!).
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As the table is swung into place, the fence fits in behind the drum, and the dust cover clips over.
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The fence is then just clamped in place. As can be seen, dust control after the test (below) was OK.
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I then ran some badly washboarded Silky Oak through, as in previous post.
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Which gave acceptable results, given the drum was still in its “raw” state.

The final “fine tuning” will be to smooth the drum, and bring it accurately parallel to the fence. For this I will make up a “sanding board” from scrap melamine, and glue coarse sandpaper to it. After removing the sandpaper from the drum, and then running the unit, I will “sand “ the board through successive fine passes, until the bare drum is true, and parallel to the fence, thus negating both inaccuracies in turning, and in the fence. I’ll post when complete.
I will also source some more suitable sandpaper than the 50year old standby roll I have used here. Suggestions on suitable grits for this purpose welcome.
regards

[stevemc32]

Great write up Alastair, looks like it'll do the job. :2tsup:

[walcen]

Thanks mate, this is a really inspirational thread :2tsup::2tsup::2tsup:.
regards

Wal

[soultrader]

Hi . Ive got a stew mac well its pre , drill press planer , thicknesser its a nice, sweet piece of design . so simple . Want photos , tell me . Cheers Andy.:2tsup:

[Alastair]

Hi all
This has had its first run in anger in the last week or so. While no JET widebelt sander, it has given me some options which are proving quite useful.
I re-trued the drum, which had moved a bit with the season, and replaced the abrasive with one cut from an 80G belt sander belt, which was just the right size. With the unit set up again, I had at the makings for the new classic.
The bottom line has something to do with sending a boy to do a man’s job. Some things it does well, others it manages, and some it is only marginally suited for. Still, over all, it has made the prep easier, and certainly more predictable.
Does well:
Cut headstock veneers from IRW, Jacaranda and Imbuia on the bandsaw. These were consistently taken down to 1/16th, and 1/40th well enough to be used as is, with a surface scrape after laminating.
Sides were taken from 5mm badly washboarded off the bandsaw, down to a little over 2mm. This is perhaps the most useful function. The sander is not overloaded, and the result is consistent. It just takes a while, many passes, and if you are not consistent with your feed rate, can be left with some drum marks. However these were shallow enough to disappear during final scraping and sanding. Compared with trying to plane from both ends, a real bargain.
It will also make accurate preparation of lining stock, and bindings, a breeze.
Copes:
My back is 3-piece, (due to depth limitation of bandsaw, and availability of quartersawn Silky Oak), so was able to fit in the sander height. Did the job, but the wider cut means lighter cuts needed, and many more passes. With the motor labouring, the slower feed also meant it was more susceptible to drum gouges.
That said, it still took the plates down to 2.8mm very accurately, and after glue-up, 3 cycles of planing left a clean accurate back, at 2.4mm before final scraping and sanding.
Is wanting:
A soundboard half is wider than the drum capacity. While you can put the plate through twice, after rotating 180, you are still left with a witness track on each side, about 1” from the edge. Also, the wider plate, and softer material made the risk of ‘grooving “ worse. In all, a bit nerve wracking, but with being able to take down to 3mm before jointing, significantly reduced the required planing.

The blemishes proved not to be a major issue, and a couple of planing cycles have yielded a true soundboard. In fact tearout from planing was more of an issue than the sander blemishes.

All up, I’ll leave it as it is. I thought to try and squeeze out a little more sanding width, but there isn’t really enough grunt to make it worth the effort, and finishing by plane is less effort. It would only be worth it, if it could do a whole back/soundboard.
For that, I will have to look at building up a jig on my lathe, (If I ever get round to it)

regards

[old_picker]

" In the absence of a lathe, this could be done in a router jig."

mm not sure about using a router for this type of work
i sense danger - a router spins way faster than a lathe or drill
no way i would attempt anything like this with a router

apart from that all excellent stuff

[Alastair]

Perhaps I should have been more specific to method. Saw this in a link to the "rolling pin sander" on the other forum.

Glued up and roughed out drum is set up in a routing box, with the shaft accurately located. Top of the box is open, with sides parallel to the drum shaft. Router is set up to run on that open top. Straight bit is used to router plane the drum, moving parallel to the shaft, and increasing plunge as excess is removed. Initial passes are linear, with the drum restrained, and rotated into new position with each pass. In the video I saw, final passes were done with the drum free to rotate, and with it spinning as the router is advanced in a very light pass, an accurate cylinder is formed.

Clear as mud?

regards


" In the absence of a lathe, this could be done in a router jig."

mm not sure about using a router for this type of work
i sense danger - a router spins way faster than a lathe or drill
no way i would attempt anything like this with a router

apart from that all excellent stuff