Tag Archives: wabeco

AB Arboga U2508: adding a “z-axis” digital indicator

The U2508 quill only has a rather coarse indicator, merely, a printed scale (which I had to replace with a new scale, because the old one was completely worn). Still, the quill can be adjusted quite precisely by using the handwheel that will allow a rather precise adjustment, with 2 mm pitch per turn.

The machine has not enough space for a glass scale, and this would be an overkill anyway. Looking around, I found this Wabeco model 11371 digital caliper, 0.01 mm resolution, and usually accurate to within 0.08 mm – most are better than that. The price is quite reasonably, found one set for EUR 38.99, delivered.

For such price, don’t expect too much precision – the mounting holes were quite off-position, and Wabeco confirmed that this is quite common for these units… well, you have to machine the bracket to the caliper’s mounting dimensions, but we aren’t going to produce these brackets in series anyway.

To connect the indicator to the quill rod, a quite sophisticated piece was machined from a scrap piece of high-tensile aluminum alloy.

A few holes drilled and tapped, and – it’s working quite fine.

Another view…

For the mounting of the readout unit, a simple strip of brass was found to be good enough, mounted with two M3 screws to the U2508 – so it can be easily removed, in case the future owner of the U2508, if any, doesn’t like the addition.

Some tests were done, and within 20-30 mm of travel, I could not find any measurable deviation. Don’t have any long gage blocks here but may check it later in case I need super accuracy for some special work.