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I had the same problem with both a U3 and a Compact 5.?? Similar Emco lathes with the same problem.? I made new keep plated from brass for the Compact 5, no help, so I measured the width? of the keep plate pressed on the bottom of the carriage, marked the keep plate and filed a shallow step that took up the play, leaving less than .001" play between the keep plate and the bottom of the bed, measured by lifting the carriage with a dial indicator on it. It took a lot of careful filing and checking, but it works better. I think a better repair would be a set of stepped retainer plates bolted to the bottom of the carriage with adjustable gibs similar to the one on the cross slide,bearing on the bottom of the bed.? Someone else did some similar work on a U3 carriage and documented it on either the unimat forum or the U3 forum.

Chuck Daldry

I’ve noticed the carriage on my U3 can lift slightly. If I grip the front of the carriage I can rock it very slightly from side to side. This allows it to yaw a fraction - it cuts on the back as well as forward stroke.

Assuming that the gibs that hold the carriage down on to the bed were worn (Emco call them ‘keep plates’) I made some new ones (twice as thick - 6mm oilon) - fitted them today but it has made no difference.

I’m thinking it can only be that the base of the carriage is somehow lower than the bed, so the gibs aren’t pressing the carriage down properly on to the prism. I can’t imagine that the underside of the bed can be worn, or the top of the bed (considering the carriage is aluminium).

Has anyone else come across this, and, if so, how did you rectify it?

Thanks!

While more dimensionally stable than other cuts, quartersawn wood is still subject to expansion, warping, twisting and cracking like any solid wood.

Sure, any wood can bend or twist due to the tensions in the tree unlocked by processing.

Quartered wood is far more likely to remain dimensionally correct though (rectangular) with changes in humidity, whereas wood cut ‘through and through’ will cup.

Yes, I would use plywood too… but the OP was talking about using timber for the sides, and ply for the top and bottom.

The dovetail is undoubtedly the king of wood joints, mechanically sound even without the glue. I always preferred ‘half blind’ rather than ‘through’ dovetails. Well worth learning to do by hand (machine dovetails are generally awful to look at IMO). Bear in mind that for a soft wood you need very sharp tools, or the fibres will just ‘squish’. If you’re using a softwood like pine make the dovetails tight and as you bash them together (er, sorry… ‘assemble them’) the wood will compress to give a really good fit.

Yeah, some ply theses days is appalling quality. ?Pine shuttering ply is almost better! At least they know how to deal with voids and overlaps when they make that stuff.

The multi-lam birch ply (you folks stateside seem to know it as Baltic ply) is probably the most consistent, almost an engineering component. The thinnest versions (1.5mm or even 0.8mm) are great for laminating around formers - any shape you like! ?I think it was developed (along with advanced wood glues) to build the wooden Mosquito fighter plane in WW2.

You probably get what you pay for. Marine ply is of a very high quality, but with a high price tag!

(Wood was my first love… I’m learning to like metal too.. :-)

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Caution:? Viewing this video may result in need to save money so you can buy this cool tool.

Ideally the timber should be quarter sawn. Imagine a board taken right through the middle section of a tree (discarding the heartwood). The annular rings run vertically, and any movement (distortion) will be minimalised - it will shrink or expand in a much more regular manner, keeping its rectangular shape.

By comparison a board cut ‘through and through’ is much more likely to distort. The wood in Kevin’s photo looks close to quartered, good regular ‘rings’ on the surface instead of a wide, chaotic figure (rings not hitting the surface at 90 degrees). A bit of Googling will explain it better than I can.

The other thing is to obtain timber that has been properly dried, rather than some intended for building work (and thus just air-dried). You could look at recycling (‘upcycling’?) a pine chest of drawers or other item of furniture maybe. You would know that it was properly dry.

I’m in the UK so things will be different here. Years ago there seemed to be a much wider range of softwoods available. Shelves were often made of ‘Piranha Pine’, and you could buy the incredibly stable Yellow Pine used in pattern making.

Ply does have the benefit of consistency (usually)!

Tamra, my two boxes are solid wood sides with plywood on top and bottom. I can make box joints fine and have all the tools needed for this. I am trying to identify the wood used in my box. It is very stiff and very light. Under the stain, it is a honey-blond color.

I already have my design laid out and the table saw is ready to rip. I supposed I need to take the two-hour roundtrip drive to the "good" lumber yard in my area and have them identify it (and sell me what I need). But I wanted to try to pick the wood up locally at our "less-than-good" lumber yard. They won't know what it is, but they can get me whatever I want to order and then do the basic ripping to save me some saw time.

If I find out *for certain* what it is I will post back here. I was just hoping we had a carpenter or cabinet maker amongst us here who knows this specific box. I don't need it to be an exact copy, but using solid wood with box joints is a part of the plan, as is the nailed-on top, hardware, and the Unimat tag. I will probably stain it walnut, as one of my two boxes has that and it looks great to me. (The other is a more reddish-brown that I like a little less.)

Thanks, everyone!

Wade