has anyone of you yet experimented with a Sparse Ruler layout for the wasteboard?
I found suggestions on this circular and the golden ratio layout, but nothing with the keyword sparse.
So, with the sparse layout you’d be able to measure all multiples of a unit up to a maximal value, with a minimal set of pre-defined measurement marks. There is a whole lot of configurations for different lengths at Wikipedia.
A wasteboard layout, using the measurement marks as drill hole locations, may then look like this (I used the spacing set {0, 1, 2, 6, 10, 13} on the x and y axis with a unit equal to 20 mm):
In order to fill the whole wasteboard, one could probably use different spacing sets along x (e.g. {0, 1, 2, 6, 10, 13}) and y (e.g. {0, 1, 2, 3, 6, 10}) and choose the scale such that the result is a best fit.
What do you think about this?
Can someone share expierence on the feasibility of such a layout?
clamp spacing needs to be less than the distance of the longest reach of the clamps you wish to use (edited)
it’s a pain to install inserts many of which won’t be used for a long time if ever
if I ever do inserts again they will only be made as and where needed, and will be made from a master file which drills through the spoilboard and a spacer installed on the baseboard, then both will be removed, a countersink will get machined in the bottom of the spacer, the threaded insert installed, then the spacer and spoilboard reinstalled ---- I might start putting threaded inserts into the baseboard if I go this route
I understand why you would want a spacer when machining holes through a spoil board as to not cut into the baseboard, but why install the spacer, for screw clearance?
Yeah, but less than half is probably better/more flexible — I go back and forth on this — I should probably land on the side of shorter spacing.
Griff
(Well crap, my hypometric precursor device is blown…)
6
What I do these days, since I mostly use tape/CA for work holding, is drill the spoilboard on 2” spacing then only install inserts as/where needed. I use brass inserts, installing, removing them for an XL wasteboard was tedious.
No matter what you do, those holes will always be just too close or just too far from almost every workpiece.
My current wasteboard has alternating M5 inserts and 8mm dowel holes 45mm on center. Dowels always are helpful. I’m undecided on the placement, though. I’ll probably offset the holes next time as I can’t use the m5 holes on the same row as alignment dowels.
That’s something that the sparse ruler layout should overcome.
Say, if your clamps reach 10 to 30 mm, they have a range of 20 mm.
If you use that range as the base unit for the sparse layout, then you can cover every workpiece width/heigth in 20 mm steps. The clamp range then covers the range in-between those steps.
But yes, i guess in practice I will quickly approach some unexpected restrictions
So, as soon as I get my clamps, I’ll give it a shot and see what happens.
I just made a new MDF wasteboard and don’t realize the tedium people have over this process. I designed a standard 50mm hole spacing and the CNC milled the holes in about 4 min. I then pull it out, flip it over, and hand countersink all the holes in a couple minutes. Then I grab the threaded inserts and drill them into all the holes in a few more minutes. Then I’m ready to face it and good to go.
I don’t see how reducing the holes saves you much time considering you’re still spending the time to design it and set it up, you might as well add more holes, not less. The time it takes to countersink and drill in 50 threaded inserts compared to 75 is maybe another minute or two.
I think it’s a little more tedious when you have to tap the holes in a metal base board, and even translates to dollars saved when paying someone to machine one. You save money on those threaded inserts haha.
How are people attaching wasteboards to baseboards? On my last set up I drilled holes from the top of the baseboard and screwed in the threaded inserts from the top - it worked fine. Do people actually machine the baseboard then disassemble to install threaded inserts from the bottom only to check calibration all over again?
Oh, I absolutely agree when it comes to aluminum wasteboards!
I milled holes and screwed my MDF wasteboard one down in 6 points across the board in the corners and the center. I can’t speak on what people do with baseboards since I haven’t changed mine yet.
Probably slightly less than [twice the longest reach] * sqrt(2) / 2 would be a compromise. That would take into account if the clamps are facing diagonally (i.e. 45° to the x- and y-axis).
So, I just installed my first proper wasteboard and wanted to share the result.
My clamps can reach from 3mm to 33mm (measured from the center of the threaded insert that the clamp is mounted to).
To account for diagonally facing clamps the maximum reach reduces to somewhat above 23mm ([longest reach] * sqrt(2) / 2).
The range that two opposite clamps can cover (along x and y) is then ([max reach] - [min reach]) * 2 = about 40.
I then selected the optimal sets of Sparse Ruler markers that fit with the calculated clamp range in order to cover the working area of the Shapeoko (individually for x and y; a padding was considered because I drilled 12mm holes with a 6mm bit).
The threaded inserts are ebedded to about 5mm. The plan is to surface the board as required and eventually add a new 3mm MDF board and install it via the screws in the very corners on top of the current wasteboard.
If I’m not mistaken, this layout should be able to handle any arbitrary stock size within the working area, with a minimal set of threaded holes.
If the clamps would reach further, or the reach is not adjusted for diagonal clamping, then the number of holes reduces further as shown here:
First mistake I noticed: The clamps on the very are too close to the edge of the wasteboard. Another drawback maybe, that, while one will always be able to find a thread next to the stock corners, additional threads along the edges of the stock may be missing for additional fixture.
If someone is interested in this, here is the matlab script I used to calculate thread locations and to try different layouts: sparseLayout.zip (1.1 KB)
haha.
Enjoy and optimize away.
