Dowel Making - How to sand accurately?

[DougVL]

I've been looking for ways to make small dowels. Well, really they'll be knitting needles and arrows. I'm still hoping to find a jig design that I like for cutting dowels from square stock. Until then, I rip squares and plane them fairly close to round in a long v-block. Knitting needle diameters range from about 1/8 inch to 3/8 inch. Knitting needles would be 8 to 15 inches long. Arrows have less size variability, about 5/16 to 3/8 inch diameter and 30 inches long. Next I want to sand them to accurate diameter, and very smooth. I've looked into the methods used for centerless grinding similar things made of steel, but haven't figured out a way to do it at home on wooden parts. It seems like the smoothest surface will come from sanding with the grain, though, which is not the way a centerless grinder works. I've got a drill press with sanding drum and I clamped a v-notched guide next to the drum and tried sanding that way, rotating and pushing the wood shaft between the drum and guide notch. But it failed miserably, probably because I seem to need infeed and outfeed guides to hold the stock straight and steady. The initial trial was with strips of bamboo which I split and then planed to approximately 1/4 inch in diameter. The bamboo isn't completely straight, so as I turned my end, the rest wiggles around. It seems like that shouldn't matter with the v-block holding the workpiece at a constant distance from the sanding drum, but it sure didn't work.

Does anyone know how dowels are sanded in large quantity? I mean what kind of machinery and what shapes of abrasive "cutter" do they use? As well as the sanding drum, I also have 1x42 and 2x48 inch belt sander/grinders that I could try making guide fixtures for. If I knew what to do!

If I can find a good way to do this, I'll take some pictures and write up a description and put the info on my website for others to see.

Thanks for any help!

-- Doug VanderLaan, K8RFT

"Sometimes history doesn't repeat itself. It just yells 'can't you remember anything I've told you?' and lets fly with a club. "To be great is to be misunderstood." Ralph Waldo Emerson -- John W. Cambell Jr.

[Greg Postma]

Doug, strange you should ask about dowel sander, I just rebuild one for export. Here is my take on take dowels in a production environment.

1. Wood is run through a molder that cuts half the dowel and then the wood is run through again to finish the rough dowel blank.

2 The rough blank is run through the dowel sand (see

and search for item number SD 10275) this shows a dowel sander. Look at the pictures, especially picture 3. This picture shows 2 groups of 3 rollers on an aluminum plate. Each group of rollers has 1 driven roller and two idler rollers. The driven roller has a shaft that extends through the aluminum plate and the shaft has a gear that rides on a stationary gear. As the aluminum plate if rotated by a small electric motor, the driven roller turns the sanding belt.The idler rollers can be adjusted to to change the gap between the two belts, for various size dowels. The dowels sander pictured can handle diameters from .4" up to 3

3/4".

Hope this helps and if you have any questions that I might be able to answer for you, please feel free to contact me off list

Greg Postma

DougVL wrote:

[David]

[David]

[DougVL]

Thanks, David. There's no making the wooden shaft round or to any specific diameter there, though. They bought ready-made dowels and put on the points and ends.

Doug

.

[DougVL]

And thanks again for the link and the ideas. But again, there's no woodworking, just using ready-made dowels.

Doug

[DougVL]

Greg - Thanks! I've heard about cutting half-rounds twice on a moulder. That's one of the "plans" I doubt I'll be able to use at home, though. I realize you weren't suggesting that part, but I just wanted to mention for other readers that it would need a special-sized cutter for each diameter needle or arrow, and I hope to make 8 or 10 different sizes.

The pictures of the machine do really help a lot! Pretty ingenious, rotating a belt sander or two around the workpiece! How fast does the aluminum plate turn?

(However, I think this device is a bit more complicated than I'm ever likely to build.)

Doug

[J]

Roy Underhill takes a thick piece of steel. Drills a number of progressively smaller holes in it (actually this is two steps drill a hole and then enlarge it most of the way through with a larger drill so there is only a lip near the edge - cuts down on friction) and then draws the stock through it. Kind of like a round scraper. Ensures the dowel is perfectly round.

-j

[Andy Dingley]

I'd suggest O-1 "gauge plate". You can buy this from any engineering supplier - it's the standard steel for making small jigs and tools. Supplied with a ready-ground flat surface, it's easily hardened and tempered on a kitchen stove. Instructions are usually on the packet.

No more than 1/32" steps in the sizes.

My own dowel plates have pairs of holes of equal size. One set is filed (before hardening) with a triangular file to make 6 teeth separated by 6 gaps (about 50:50)

By forcing the rough dowel through the toothed holes, you can more easily remove timber form the outside. Starting large and working down the sizes, you can reduce bandsawn squares to dowels of any size.

Easier to use a tapered reamer from the back

Personally I work with 8" lengths and drive them through with a small hammer rather than pulling them. Support the plate over a bench dog hole.

You need good technique to get good dowels with a good surface. Small size increments help too - it's quicker to take two light scrapes than one heavy one.

[Prometheus]

While I'm sure it's fully possible to do this with another method, I would think your best bet would be to get yourself a cheap mini-lathe (or an expensive one, depending on your budget for this) and turn the square stock between centers. You can rough something like that out in about 20 seconds, and then make a jig to hold a piece of sandpaper that stretches the length of the piece parallel to the centers for your finish. Works good for other stuff as well, and I've seen them for as little as $70 recently. I couldn't tell you how well a $70 lathe works, but I'm sure it makes the parts spin around, and if all you're making is dowels, that might be enough.

If you don't want to buy a lathe, but have a drill press, you could mounting the piece vertically and setting up something to take the stock off evenly while it turns- but make sure to support the bottom of the dowel somehow (maybe with a tip of a nail driven through a board set on the base) so that it doesn't come flying off on you.

Aut inveniam viam aut faciam

[Greg Postma]

Well Doug, this is your lucky day To test the machine before I exported it, I ripped some stock to square blanks the I used a router table to make the rough dowel blanks and then ran them through the dowel sander.I used 120 grit belts and the finish was smooth. The aluminum plate ran about 200-250 rpm (my best guess).

If you want to cobble together a machine like the Lobo dowel sander, I think that with a little ingenuity and a couple of these

a method of rotating the dowel blanks as they passed between the belts, you could make some accurate dowels

DougVL wrote:

[Charles Spitzer]

look into how they make round wooden pencils?

[DougVL]

I forgot to mention that I had also made dowel plates, with holes taper reamed from the back. One is drilled with drills by 64ths of an inch, and another with number-size drills. Drilling two of each size and toothing one sounds like a very good idea for the next dowel plate. And I also made another plate sort of on this principle, from an article in Muzzleloader magazine. It was about making ramrods. The plate has a row of holes drilled like the dowel plate, but then a V-shaped slot connects the sides of the hole to the edge of the plate. The edges of the V and of the remaining half-circle are beveled from the back, like dowel plate holes. I clamp it in my bench vise and pull square sticks through it.

Let's see if that works in ascii art:

-______________ _____ | \ / | | \ / | | U | |______________________|

Well, if you mentally make that U into the bottom half of an O, that would be it. With this one, you pull the stick thru the slot, shaving strips off the sides, then rotate a little and pull thru again. Repeat until stick fits diameter of hole at the bottom, and then it's a dowel. This works easier and faster than my dowel plates.

But both leave rough surfaces which need a lot of sanding, because of torn grain. Even with the very straight grain in the split bamboo.

Doug

[DougVL]

I have a wood lathe, but turning 15 inch spindles as thin as 1/8" and 3/16" is well beyond my capability. And so is turning 5/16" shafts 30 inches long. If anyone does do this successfully I'd very much like to see pictures of their setup!

Doug

[DougVL]

The only pencil construction method I've seen was two halves grooved for the lead and then glued together. Doesn't seem appropriate for my projects, at least partly because of the need for so many different cutters for different diameters. Assuming the use of the spindle moulder method. I wonder how they sand the pencils smooth? Thanks for the suggestion, though.

Doug

[Charles Spitzer]

i meant the outside of round pencils. not all are hexagonal. i've actually seen them do hex pencils. they make up boards, vgroove them, and then cut them apart.

[Andy Dingley]

Same way as dowels - a variant of the "centreless grinder"

You could make one of these up fairly easily, but you'd have to want an awful lot of dowels.

[DougVL]

Hmmm. I have two pairs of 1X42 sanders already! Two Rockwell Delta, and two Arco. Rotating the dowels wouldn't be hard. I've read about doing with an electric drill. This would actually be a bit like centerless grinding, too.

Thanks for the idea! This has real promise.

Doug

[DougVL]

Might be able to make one, if I'd already seen similar machinery.

Most of my working career has been with companies that build custom machinery, but I haven't seen anything that performs the type of operation I'm looking for. But most everything I've seen or worked on has been metalworking machinery or food processing machinery.

Do you know where I could see pictures of some variant of a centerless grinder? Besides the Lobo at XFactory that Greg posted the link to?

Thanks,

Doug

[Prometheus]

I've never had the need to make a dowel on the thing, but I've made several pieces that had sections that thin on my Delta midi. Maybe a couple of steady rests would make it a little easier. But I do see your point- .125" is awfully small on a lathe.

Aut inveniam viam aut faciam