Slip rolls. Again...

[Richiew]

Some welding today. I always pick the hottest days to do it. Was soaked through by the end of it all but the air fed mask helped enormously to keep me comfortable. Bevels were ground into the frames yesterday. The bushings and bearing carriers were left fitted to aid alignment when tacking up with the MIG welder. A quick check to make sure nothing is stuck and tacks are made.

MMA welding using 3.2mm 6013. 128 amps. Managed to get some peelers. Kept welding opposite sides to stop heat causing trouble. Plenty of checks done to see that the carriers still fit and move freely. For MMA welding, the vice was placed on a stool next to the table. It was a good working height compared to the vice on top of the table. I used the table as a support for my left elbow, which helped.


The welds aren't very big or deep considering the size of the plates, but I don't think the forces on them will be too much. I can always cross drill and fit some pins to help keep the plates together if need be.

These are the best two sides. I wanted to do them all in one pass, so some weaving action was employed to get full coverage.

A few hours later after everything has cooled down. Everything still fits and moves like it should so that's a big hurdle crossed. I will smooth off the welds on the bottom edges, the frames need something accurate to sit on. Will leave the rest until I've got it all working. Can always tidy things up if need be once I'm satisfied the frames won't split.

 

[Richiew]

Small and steady progress.
Couple of days ago, I braved the garage in the middle of the heatwave and milled off the welds from the bottom edge. 20 minutes work, and then I found something else to do, away from the heat.

Back in the garage today now it's much cooler. Marked out and centre drilled. There wasn't enough spare height to get a reasonable sized drill in the chuck so onto the big drill after this. The mill table was all the way down in this pic.

Started with 8mm then 1/2" 5/8" and finally 45/64" which should give me 66% thread depth for the M20 by 2.5 thread. I have some Presto taps coming any day now. The mill will get used to line up the tap and keep everything straight.

The top right hole is a tiny bit off but it's fine for what I need it to do.

 

[Richiew]

Taps arrived.

I am a master at tapping and die threading on the wonk so opted to tap the frames in the mill to keep things lined up. There's an R8 to MT2 adaptor in the mill to accommodate the bull nosed live centre from my lathe. Used this to line up the drill holes with the quill centre.

Swapped out for a smaller half dead centre. It was the only centre I had that left enough height for the tap. There's a centre-drilled hole in the tap to accommodate the dead centre, which kept everything square and wonk free. M20 threads by hand.

Test fit with threaded bar, all good.

All sorted. Will drill the end holes in the bearing carriers next. Decided that the pair of holes on the face of the bearing carrier for retaining roll pins are unnecessary. The block gets pushed up from underneath and the pressure will keep it connected to the screw when tightening. There's gravity to assist when unscrewing. It would be different if the screws came down from the top but this isn't the case.

 

[Richiew]

Next bit sort of done.
Used an edge finder and the DRO to find centre on one of the blocks. I had four to drill so fitted a stop to the vice jaw and lined up the block level with the edge of the vice beforehand. The four blocks are from the same piece of stock, this allowed me to swap them over in the vice and be fairly confident of repeatability.

Chopped up the one-metre length of 20mm threaded bar. Had to turn down the ends slightly to fit the drilled holes. Used a collet chuck so the threads didn't get damaged.

Fitted up. Everything works as it should. I think I will need a longer screw for the long slot. I want different lengths for the screws to allow handles clear each other. The long slot does all the hard work setting the bend in the material so that one needs a bigger handle for leverage. The shorter slot screw will get trimmed. The plates will sit on some box section so there needs to be spare length underneath to clear the thickness of the box.

The next problem is cutting the internal keyway on the rollers. I think I'm going to make up a keyway broach bush with a slot but use it as a file guide. I think it is doable as the keyway is 8mm wide by 7mm deep and I only have to file to around 3.5mm depth. Start with a narrow file and work my way up the sizes. Can't harm to give it a go. I have some 8mm tool steel so I may end up tidying the filed keyway in the lathe using the carriage like a slotter. Opinions and experiences welcomed.