Homemade Lathe Headstock EXTERNAL Gearbox

[Toolmaker51]

Yes 100%. Without an X-Y [or Z] coordinate envelope to traverse an entire pair of sides, working out shaft locations individually is the only dependable alternative. Also offers previous openings for additional clamping.
I'd recommend doweling two corners to guarantee respective orientation regardless interim disassembly. The greatest repeatability is had via standard tapered dowels. With a little planning, drill and tap big ends for pull studs/ screws. They'll simplify final construction of the box too.
Another sandwiching trick is to space a few through-tapped holes in idle areas before doweling, but clamped as flat possible, then dowel prior to milling square. Then setscrews shorter than the combined thickness holds them together very well, stopping incursion of chips or burrs from holes jacking them apart. Sealing them is quite easy and varied; cap screws, Teflon tape, valve grease, drill out threads and peen in round stock...Good results peening can start with a bearing ball to 'countersink' the hole perimeter.
I'll illustrate a doweling scheme for readers and edit in; but good practice spaces dowels diagonally opposed far apart as possible, maintaining at least 1.5 diameters from edges, positioned asymmetrically to avoid matching wrong corners together. Tapered dowels don't require the effort of cylindrical and 'pull' the registry into place via the conical shape. Cylindrical dowels can shear one portion of a hole, deviating from intended position.


LMMasterMariners point about building next box after a powerfeed is well taken. For a project like this, old fashioned tooling buttons are a great substitute; moving the plate instead and minimal indicating. With decent material [a good OD finish indicates best] they'll locate intended centers within .001 readily, closer yet with sensitive test indicator and careful positioning. I don't know they are still made...But they can be made, or use small drill bushings, and of course bought used. Too many sellers think Toolmaker Buttons are some exotic deal, which is not the case, overpricing them insanely. I use drill bushings; perfect ground OD, ends very square, and come in varied length for closely placed positions.
Readers; as always, direct any questions our way. It's why we're here!
Special info discount sale today, too cold & snowy for engineering. I'm writing and rocking Spotify!