Warco WM250V jam!

[Mick B1Participant @mickb1]

Unexpected shearpin issue

[Mick B1Participant @mickb1]

It's as well to be aware that the crosslide shearpin can fall into the apron gearbox on the WM250V, and that if it does it can spoil your day for a while.

I was milling steps in some blocks of Nylon66, cutting on the vertical slide with both saddle and crosslide locked. When I'd finished and released the crosslide, I found I could only turn the handwheel a few degrees in either direction before it came to solid stop.

I fiddled with it – spindle stopped, power feed on and off longitudinal and cross. The handwheel came free, but the power crossfeed didn't work.

I tried power longitudinal feed at low revs. There was a bang and the saddle jammed solid. Pulling back the telescopic leadscrew cover showed the drive collar rotating but leadscrew stopped – shearpin obviously snapped.

I'm old enough to know there is no magic, and I was going to have to resolve this, so I finally screwed up the courage to remove the leadscrew end bracket and the apron casting and leadscrew assembly, then peer into the dirty, oily gloom of the apron gearbox… >.

At first I thought one of the teeth of the pinion on the end of the wormwheel driven by the keyed leadscrew worm was horribly damaged and that I'd have to dismantle the whole thing, but I then realised the mess I could see was actually the remains of the crosslide shearpin, crushed into the pinion's toothspace by the meshing adjacent gear. Once I'd figured out which way to turn the stuck leadscrew to rotate the pinion out of jam, I could poke the broken bit out and fix the problem with nothing more than a couple of new 1/8" brass shearpins.

[Chris Evans 6Participant @chrisevans6]

That's a good heads up for fellow owners to look out for.

[mechman48Participant @mechman48]

Thanks for that Mick; got one of those myself, will put that into memory bank…when I can remember where it is…

​George.

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