As Steamboat said, a router table or shaper will work fine, as long as the fence is tight on the bit. I've done hundreds of small hardwood pieces just like that.
But, since you're dead set on tumbling that's what you should do. You'll have to experiment.
John Martin
On Fri, 07 Aug 2009 22:17:26 -0700, the infamous Winston scrawled the following:
Cha-CHING! Hold on there. Try these:
Or hold the router in the clamp and the block with a pair of vise grips.
-- Content thyself to be obscurely good. When vice prevails, and impious men bear sway, the post of honor is a private station. -- Joseph Addison, 'Cato'
I agree - that's putting your fingers much too close to the bit.
I would make one like this: take a piece of 1 x 2 pine, maybe 6" long. Cut a 1 x 1 notch in the end:
_____________ | _____| | _________|
Take 2 pieces of 2 x 4" 1/4 plywood/Masonite & fasten to the sides of the 1st piece, making a 1 x 1 x 1 pocket. Your block goes in the pocket & is held firmly against the router table & fence.
Make a pass, flip the block & repeat 11 more times! Repeat 199 times!
You can reduce the repeat's as follows: route the long sides and the ends of your 1 x 1 stock before cutting off 1" pieces. Then you have a block with 8 sides already rounded. Route the cut end after each cut.
Bob
I like that handheld router!
Hokay, building on your idea, how about stacking & clamping nine 1" cube blocks 1 deep sideways in a vise using a 1/8" neoprene jaw cover on the bench side, resting the blocks on a bottom lip milled into the movable jaw (Think 'Parallels'):
Unclamp and rotate each of the blocks 90° and pick up two more edges on the 7 constrained blocks and the remaining edge on each of the two end blocks.
You are half done! Spin all nine blocks upside down to expose the unmachined edges and finish up with six more passes. Should cost less than 30 seconds per block on average, (not including latency). You should be able to bang out all 100 pieces in less than an hour.
Protect yourself from inhaling hazardous dust produced from machining some exotic woods.
Vacuum and clean the workpieces. Stain and seal as appropriate.
My apologies if this is not clear. Sometimes I forget that I am completely incapable of abstract thought.
--Winston
I think what you need is a Burr beaver clone:
Doug White
[snip links to routers/shapers/clamps]
Treating the end blocks differently than the others (ie, cutting across their ends) apparently makes no difference in the total number of router passes or the number of clampings, so it should not be done. Treating some parts differently than others slows things down and can lead to errors. Anyway, snipe is a problem for short planer/jointer/router/shaper cuts.
For high volumes of blocks (thousands?) I think that tumbling the blocks is a better approach than using any method that entails handling blocks individually. But if you don't mind one "rotate each of the blocks 90°" step per block, make a tube-like jig with a cross-section like a square with a corner cut off. When this magazine is loaded with blocks and the ends closed tight, the line of blocks can be treated like an uncut stick, and run across a joiner (or perhaps a sander, router, or shaper) to chamfer one edge of each block in the jig. Then push the line of blocks out of that jig into an empty jig rotated 90°, exposing a new line of edges for cutting. (Or push them out of the jig into an open v-channel, rotate the jig 90°, and push them back in.) After 4 passes, unload the jig into a v channel, rotate each block 90° to expose 4 new edges, and push the line of blocks back into a jig.
...
(...)
Good point. Rounding only the +Y and -Y edges would limit chipping and you could do the job in only 8 passes instead of 12. By extension, one could make a clamp that held say 52 pieces instead of only 9. All 100 cubes could be done in only 16 passes.
Perhaps. I've never tumbled wood but it strikes me that you could get more predictable edges very quickly by using a router or shaper. I can't quite squash the image of unintended dings caused by corners hitting planar surfaces.
That's one cut per block per setup. Previous way is two cuts per block per setup. Which would be faster?
Your square tube jig is sure adaptable to automation!
I can see a vertical square tube that contains two contoured planer knives. Press a stack of cubes in from the top and you get four edges rounded at once. Press these workpieces into a horizontal square tube. Four more edges and we are done. It would take many, many cubes for such a machine to pay for itself, however.
--Winston
On Sat, 08 Aug 2009 11:08:25 -0700, the infamous Winston scrawled the following:
Yes, Porter Cable tools are nice. I got a free handheld router when I bought my Griz dust collector and bandsaw. They're definitely handy!
See my other post this morning. Great minds think alike, but we're backwards on this one: you preferring to move the cutter, me preferring to move the blocks for mass processing.
Yes, use a dust collector, _always_!
I always wipe with lacquer thinner or paint thinner prior to finishing.
You misspelled "clearcoat", dummkopf. When you use the proper wood in the first place, you don't have to _stain_ the poor stuff. Stain ends up giving you a mottled, ugly POS.
Are you sure?
-- I'm still waiting for another sublime, transcendent flash of adequacy. --Winnie of RCM
On Sat, 08 Aug 2009 16:07:47 -0500, the infamous James Waldby scrawled the following:
Yes, tumbling is probably the best bet all around.
-- Content thyself to be obscurely good. When vice prevails, and impious men bear sway, the post of honor is a private station. -- Joseph Addison, 'Cato'
Larry Jaques insisted:
(...)
The OP stated that he needed enough pieces for one classroom but we don't know how many pieces he could envision making. There are a whole range of tools and techniques useful from 1 piece to fractional millions.
(...)
We are in violent agreement.
That'll be the thing I learnt today.
Only when I'm wrong, Larry.
It's gonna happen too. I have faith.
--Winnie
Your router should already have a fence; all you need is a featherboard and a push stick, and maybe another push stick or another featherboard.
Admittedly, it'd be a bit time-consuming, but tumbling square pieces really doesn't sound like that hot of an idea, as has been noted.
In any case, remember to wear your eye protection, and maybe hearing protection.
Good Luck! Rich
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