The manual edge fettler. Who needs a shooting board!?

[Beatsy]

OK, we all do. But for this particular task of making square sapele blocks to insane accuracy, my "manual edge fettler" works better for me. It's way more efficient and much more accurate! I struggled with the sheer hardness of this wood and the masses of grain reversals when trying to shoot it on all four edges. So I fell back to the fettler - a general purpose thingy - which worked great! Sometimes, the simplest and crudest solutions are best...

The fettler is just 150 grit sandpaper stuck to glass with a metal "fence" that is free-standing and can be moved anywhere on the sandpaper. Everything is straight and square on this fence, but a chunk of squared wood works too. Note: the "fence" is a component from an optical bench in this case - covered in masking tape so it can resume its original function, one day, maybe.

To square and dimension the edges of the sawn blocks, I simply press the reference face against the fence, an edge against the sandpaper and slide the block back and forth along the fence, applying "rotational pressure" with the right hand to tilt an edge one way or the other if needed. The edges stay flat on the sandpaper though - there's no actual or visible rotation. Generally the edges are square already and just need knocking down level. Note: the left hand usually holds the fence steady but mine was busy holding the camera here.

Checking progress (size) on the dial gauge is super quick, just seconds, and it's easy to see if edge has tilted out of square as one corner will be higher than the other. If that happens, I use the little square to verify which edge is at fault (top edge or bottom one), rub the edge while "rotating" to apply more pressure on the higher end, then check again. And so on...

I've just completed 64 squares, each 63.00 x 63.00 x 26.00 mm. I used two decimal places as I managed a tolerance of +/- 0.03 mm for the lot! Yep, that's +/- 30 microns!

Hope it's not too humid tomorrow or I might have to sand more off to get it back in tolerance...

 

[Ttrees]

I kinda do something similar with artists graphite sticks, and this unobtainium block.
Cast iron works better though.

These sticks are pricey at probably 2 quid a piece, but one has lasted me for a decade,
and very nice to use for other things like marking very heavy lines which are easily removed, compared to a carpenters pencil.
(the graphite stick only makes the alu practical, and if only the pencil is available one would need cast iron)

That and the calipers, and no edges until the two faces are done.
Very nontraditional by the Schwarz's of olde standards

 

[deema]

You got me, I’ve got to ask what are all the blocks for?

 

[Droogs]

that is a very shiny workmate

 

[Beatsy]

that is a very shiny workmate

Ouch.

Bought for "the project" but you're right, it is rather shiny. Perhaps I can up my cred some if I run a saw through it a few times...

 

[Beatsy]

You got me, I’ve got to ask what are all the blocks for?

They're for a tournament chess board. A novel "four boards in one" design I'm trying out (scratching a long term itch). The main emphasis is on the wood though (veneers). A reconfigurable chess board provides the perfect excuse to obtain more veneers to make more squares on an ongoing basis. Oh, and I can play chess on it too.

Pics quicker than words.

Here are some squares from early prototyping. Working out the process, materials, finishes and best magnet strengths etc. They've been well abused and refinished several times, so starting to look a bit tired but show the idea.

Embedded magnets hold the squares together. Squares only attract squares of the opposite colour, not their own colour.

Here's how one board makes four different ones. Squares are double sided to start with, so that's two boards, but the white and black squares can be turned over independently because they're separate (obviously). So turning over (say) the white squares gives a different double-sided combination of light/dark squares, making four board designs in total.

I'm using Kerelian maple (correction: birch) in the main board (light squares in the first frame), but none of the others. Got a lovely burl maple for one set of dark squares though, that's definitely in (cut raw veneer below). Still agonising over the other two - shortlist down to four...

The whole thing is a madness, I know. But it's my madness and I'm going to see it through to the end.

 

[Droogs]

The flame on that Kerelian maple is astounding. Never seen a cut like that, you're very lucky

 

[Adam W.]

You need this to go with your lovely shiny kit.

https://www.workshopheaven.com/schtickle-starrett-60b-100-precision-square-100mm.html

 

[Beatsy]

I kinda do something similar with artists graphite sticks, and this unobtainium block.
Cast iron works better though.

These sticks are pricey at probably 2 quid a piece, but one has lasted me for a decade,
and very nice to use for other things like marking very heavy lines which are easily removed, compared to a carpenters pencil.
(the graphite stick only makes the alu practical, and if only the pencil is available one would need cast iron)

That and the calipers, and no edges until the two faces are done.
Very nontraditional by the Schwarz's of olde standards

Looks neat, but I can't figure out what you're actually doing with the block and graphite, and now need to know. Is it for marking high spots? What makes "alu" (aluminium?) special for graphite but cast iron best for pencil lead? Thanks.

 

[Sandyn]

The whole thing is a madness, I know. But it's my madness and I'm going to see it through to the end

Madness, but quite brilliant. I think it's a really fascinating idea. Look forward to seeing how things go

 

[TRITON]

that is a very shiny workmate

Shame about the lawn.

The flame on that Kerelian maple is astounding. Never seen a cut like that, you're very lucky

Thats because it's birch .

 

[Beatsy]

Shame about the lawn.


Thats because it's birch .

Oops. My mistake. Thanks for the correction

 

[Ttrees]

Looks neat, but I can't figure out what you're actually doing with the block and graphite, and now need to know. Is it for marking high spots? What makes "alu" (aluminium?) special for graphite but cast iron best for pencil lead? Thanks.

Great Looking chess board, quite outta the box thinking there.
indeed the aluminium block is for marking the high spots.
The graphite stick is necessary for aluminium as you'd be all day trying to coat it with a pencil, and it doesn't last long either.
Been considering finding some milled cast iron as it devours the graphite compared, and likely lasts quite a while on the tool.
Having done this before on a cast iron table, I can attest that it is not easy to remove, and will coat timber in about 1 second.

All the best
Tom

 

[Knilly]

OMG! I’ve got sooooo much to learn and aspire to!

 

[johnwalls26]

I lived next door to a Taylor Hobson optical worker. Their standard of flatness they polished to was to place one polished glass surface against another known optical flat until light interference is eliminated. We don't really need that in woodworking.

 

[niall Y]

A lovely idea and well executed, but here's a thought - a square of Sapele isn't necessarily going to remain square...... I was thinking that you could overcome this by ensuring that the grain o the Sapele blocks is always oriented in the same direction. That way the complete board could be out of square, but you would avoid the niggling problem of the corners of the blocks not quite lining up This could be done using your trick with the magnets, after all it's relatively easy , to visually arrange for adjacent squares to be different colours.... Best of luck with the project

 

[isaac3d]

They're for a tournament chess board. A novel "four boards in one" design I'm trying out (scratching a long term itch). The main emphasis is on the wood though (veneers). A reconfigurable chess board provides the perfect excuse to obtain more veneers to make more squares on an ongoing basis. Oh, and I can play chess on it too.

Pics quicker than words.

Here are some squares from early prototyping. Working out the process, materials, finishes and best magnet strengths etc. They've been well abused and refinished several times, so starting to look a bit tired but show the idea.
View attachment 140967

Embedded magnets hold the squares together. Squares only attract squares of the opposite colour, not their own colour.
View attachment 140969

Here's how one board makes four different ones. Squares are double sided to start with, so that's two boards, but the white and black squares can be turned over independently because they're separate (obviously). So turning over (say) the white squares gives a different double-sided combination of light/dark squares, making four board designs in total.
View attachment 140970

I'm using Kerelian maple (correction: birch) in the main board (light squares in the first frame), but none of the others. Got a lovely burl maple for one set of dark squares though, that's definitely in (cut raw veneer below). Still agonising over the other two - shortlist down to four...
View attachment 140972

The whole thing is a madness, I know. But it's my madness and I'm going to see it through to the end.

Madness! Yep, absolutely! On the other hand, go for it dude. It's beautiful.

 

[Beatsy]

A lovely idea and well executed, but here's a thought - a square of Sapele isn't necessarily going to remain square...... I was thinking that you could overcome this by ensuring that the grain o the Sapele blocks is always oriented in the same direction. That way the complete board could be out of square, but you would avoid the niggling problem of the corners of the blocks not quite lining up This could be done using your trick with the magnets, after all it's relatively easy , to visually arrange for adjacent squares to be different colours.... Best of luck with the project

Thanks,

Warping is a concern and I spent a long time deliberating over what substrate to use. I initially tried marine ply, but dimensions and quality are all over the place these days. The facing veneer is usually terrible too; often dead thin (0.3 mm), soft and poorly glued. About as far from a stable substrate for "difficult" veneers as you can get - especially for veneers covering blocks that will be continually handled, clacked together and dropped.

That prompted me to look at mahogany next, a wood I know from my boatbuilding days (in a previous geological age). The cost of Honduran mahogany was a bit steep and I couldn't find a supplier of machined stock to my specs. Second choice was sapele, which I've also used. Kiln dried is stable but I've seen long sawn boards twist and bow over the course of a year in storage. Not badly though. Given the relatively tiny scale of my blocks, and that they're locked away behind waterproof adhesive, veneers and water-resistant/proof finish(es), I think they'll be OK. Also, by working to *really* tight tolerances now, I leave more leeway for future shifting to remain undetectable. Small chamfers on the dark, smoked oak borders around each square can hide up to 0.15mm misalignment (I tested that). So by working to insane tolerances now, I leave leeway for the board to absorb some warping over subsequent years too - if it happens at all.

Note: I can't pre-orient grains as the squares can be positioned and re-positioned any-way-up by the end-user (me). This to align grains and features to taste, or to "optimise" for light direction where the board lives and orient individual squares to look their best, etc. That's a key "novel feature", so it stays.

Someone's bound to ask, and yes, I tested MDF too. Apart from disliking MDF on principal, it's actually a bit too dense. Sapele is about 15% lighter which avoids a need for stronger magnets - at >3x the cost of the ones I already got! With all factors considered, sapele was the best choice - I think.

 

[Droogs]

Have you considered using CDF from Kronoswiss

 

[Beatsy]

I hadn't heard of it till now. I assume you mention it for the 30% weight saving over other laminates. Pretty light.