Reference specs, per-sheet math, and router starting points for 18mm Baltic birch — the void-free ply for signs, cabinets, and furniture parts. Punch in your sheet price below for an instant per-part quote.
Baltic birch is the router shop’s default ply because every inner ply is solid birch: no voids for a bit to break into, and edges that take a roundover or finish without filler. The traditional sheet is 5′ × 5′, so check your machine’s bed before you buy.
The catch is tear-out. An upcut bit lifts the top veneer; a compression bit leaves both faces clean, provided the first pass goes deeper than the bit’s upcut section.
The same math the calculator above runs — worked out longhand, so you can sanity-check it against your own numbers.
On a router the kerf is the bit itself, 0.25″ against a laser’s 0.008″, and every part needs tabs or hold-down clearance. Nest 5 3/4″ squares on a 4×8 sheet: a laser fits 128, a router 105 once each part has the 1/4″ bit and another 1/4″ of hold-down clearance around it, about 18% fewer, which is why the scrap allowance here is higher than on the laser pages. CNC makers report well-nested shops running 82–92% sheet use (Laguna).
This is the material line only. KraftyQuote’s router rows add the machine time, with depth passes counted: 0.709″ at a 1/4″ step-down is three passes, at 0.10″ it is eight.
Published starting points, not settings to run blind. Hobby machines aren’t as stiff as the industrial machines tool makers chart for, so start at the hobby row and work up. Stepover for pocketing about 0.11″ (44% of a 1/4″ bit). Feed = RPM × flutes × chipload. Start at the low end, listen, and look at the chips: fine dust means the chipload is too small, which heats and dulls the bit.
Yes. It is 18mm, 0.709", about 1/32" under 3/4". Size dadoes, slots and joinery to the thickness you measure, not 0.750".
13 plies, all birch. The void-free core is why it holds screws in the edge and takes a roundover cleanly.
A compression bit: it cuts up at the tip and down along the shank, so both faces stay clean. Make the first pass deeper than the upcut part of the bit, or the top face can still lift.
Divide the thickness by your step-down and round up. 0.709" at 0.25" is three passes; at a cautious 0.10" on a hobby machine it is eight. KraftyQuote counts this for you on a CNC router row.
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