Mostly metalworker needs woodworking advice...

[Pete C.]

I dabble a little in wood now and then, but I'm mostly a metal guy.

I unfortunately have a project that requires me to produce a large number (hundreds) of nominal 1.5" - 2" dia x .5" - .625" thick wood disks probably from a decent hardwood. End grain should be on the side of the disk.

I need to figure out a way to produce these disks in an efficient manner and with good surface finishes. They can't have a center hole. A regular hole saw (without the usual pilot drill) in my mill gives a lousy finish on the outside of the disk and very inefficient disk removal from the hole saw.

Any single point cutter like the adjustable circle cutters or a CNC router will mangle the disk when it breaks free at the bottom of the cut without an elaborate vacuum clamping system. Leaving the cut just shy of the bottom and then running the sheet through a thickness planer might free the pieces, but I'm not sure that a thickness planer can handle feeding the loose 1.5" pieces on the outfeed and keeping them from flying up into the cutter.

I see all sorts of cheap little wooden toy wheels and whatnot so there has to be an efficient way to produce these, but I'm not sure what it is.

Help!

Thanks,

Pete C.

[brianlanning]

Why wouldn't the circle cutting jig work? Just put a backer board behind it.

brian

[Pete C.]

As soon as the disk breaks free, with the cutter circling around it will shift to the side and jam mangling the edge (yes I tried it). The same happens with CNC router, once the disk is free it jams and mangles (tried that too). Only some sort of vacuum clamp below might fix that problem.

Pete C.

[Teamcasa]

Just thinking out loud. Make a dowel the right diameter. Slice of the disks. Drop them into a plate that has the same size holes as the dowel. Run through a stroke sander. Or make a simple vacuum sled that holds dozens and run through a planer.

Dave

[Pete C.]

I thought of something similar, but all the dowels I've seen have the grain along the axis which is opposite of what I need.

Thanks,

Pete C.

[Teamcasa]

Turn your own dowel. Dave

[Chris Friesen]

What about masking tape across the disks (on the underside as it goes through the planer) so they don't get sucked up?

Chris

[Sergey Kubushin]

Did you try double-sided tape?

[Pete C.]

No, but it doesn't sound too practical for the volume I need. For a dozen sure, but for a few hundred...

Thanks,

Pete C.

[Pete C.]

In order to turn a dowel with the grain running perpendicular to the axis either the dowel wound be very short or the raw stock would have to be from a huge tree. I'm also not equipped to turn 2" dia dowels very efficiently.

Thanks,

Pete C.

[Australopithecus scobis]

Start with thicker stock, say 1.25 or so, barely wider than your final diameter + cutter width (2.25 or so). Cut holes _part way_ through; 0.7 deep. Run on edge through table saw with spiffy blade. The guys who cut their own screw-hole plugs can give you the details. You might have to run some tape across the tops of the partially-cut forms so they don't go hopping about when the TS frees them from the stock.

Because you're a machinist, perhaps you could cobble up a two-blade circle cutter. First blade is outboard, and cuts first (deeper). Second, inboard, blade makes the finish cut.

[Pete C.]

That might work, but a vacuum tray might be more practical for production. Problem is I don't have a thickness planer to experiment with so that would be a $200 investment for a cheap one to test the idea.

I'd like to know how the very common toy wheels are being produced, the volume is clearly huge so there must be some good trick to it.

Thanks,

Pete C.

[John]

Assuming that you already have the dowel turned to the appropriate diameter, slice off slightly oversize discs. A bandsaw will waste less wood due to the thinner kerf but if you only have a chop saw then I guess you'll just have to turn a longer dowel. To clean up the rough faces, mount each disk in a drill press vise or a custom made wooden jig that will hold the little disc without letting it revolve. Mount a sanding disk in the drill press chuck, press and sand. Flip the wood disc over and repeat. If you want a really fine finish on such little pieces then repeat sand with a finer grit of paper.

No sanding disk? Make one out of steel pipe and glue sandpaper to one end of it. Chuck the other end in the drill.

As an alternative to sanding, maybe a small rosette cutter in the drill press would work for you. Since you're a metal worker you could probably fashion your own for such small diameter work.

J.

Pete C. wrote:

[Pete C.]

Hmm, running the stock on edge and using the table saw a bit like the thickness planer? Let the remaining stock act as the pusher / carrier to move the disks along. That might work, I do have a table saw.

I think that a single tooth carbide hole saw will leave a good finish as long as I don't cut full depth and have the disk stick inside the saw. Should be easy enough to make a jig to run a 1x3 under the hole saw in my mill.

Thanks,

Pete C.

[Pete C.]

The problem with the dowel is that the grain will be running in the wrong direction. These disks need to look good plain or with a light spray or dip finish.

Thanks,

Pete C.

[Rick Samuel]

Assuming you have a >metal lathe

[Morris Dovey]

| I dabble a little in wood now and then, but I'm mostly a metal guy. | | I unfortunately have a project that requires me to produce a large | number (hundreds) of nominal 1.5" - 2" dia x .5" - .625" thick wood | disks probably from a decent hardwood. End grain should be on the | side of the disk. | | I need to figure out a way to produce these disks in an efficient | manner and with good surface finishes. They can't have a center | hole. A regular hole saw (without the usual pilot drill) in my mill | gives a lousy finish on the outside of the disk and very | inefficient disk removal from the hole saw. | | Any single point cutter like the adjustable circle cutters or a CNC | router will mangle the disk when it breaks free at the bottom of | the cut without an elaborate vacuum clamping system. Leaving the | cut just shy of the bottom and then running the sheet through a | thickness planer might free the pieces, but I'm not sure that a | thickness planer can handle feeding the loose 1.5" pieces on the | outfeed and keeping them from flying up into the cutter. | | I see all sorts of cheap little wooden toy wheels and whatnot so | there has to be an efficient way to produce these, but I'm not sure | what it is. | | Help!

Pete...

I'd go with the CNC router. In that context "hundreds" isn't "a large number"!

If a disk need not be cut entirely from a single board, you can save time and waste less wood by gluing up panels and routing the panels rather than individual boards.

Cut the pieces free except for 0.01" (or thereabouts) at the bottom of the cut. Run the workpiece upside down through a wide-belt thickness _sander_ and remove 0.01". The freed workpieces will be captured in the scrap and have good finish on (at least) the sanded side.

If you don't cut all the way through the board/panel, a simple vacuum clamping system will work quite well. I use shop-made "pucks" and a recycled refrigerator compressor for exactly this kind of work in my shop (my last comparable run cut hexagons rather than circles; but it's essentially the same problem).

You can also use a simple mechanical clamping system as your cutting program knows where the clamps are. :-)

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

[CW]

[CW]

Lathe.

[Pete C.]

No big CNC lathe and the dowel would have the grain in the wrong direction.

The biggest problem is the volume I need, too large for fully manual production and too small to justify building a fully automated setup. Sanding tabs adds labor that makes it less practical.

Thanks,

Pete C.