How to make one of these (hardened steel lever)

Fold one up from M.S. plate, drill and tap, check fit, then case harden either just the four holes in tne vertical limbs, or the whole thing for a bit of extra stiffness. Make two while you're at it (won't take twice as long) and you're covered for life.

John

I have found numerous exploded diagrams of Bosch jigsaws and seen lots of very similar looking parts but not seen any that are identical. One of the Bosch dealers assures me that none of the available spares are exactly equivalent and although there are one or two parts that look is if they 'might' fit I would have to order them specially to find out, so it could get expensive.

Ian P

Howard

I think you are right, welding might work and little to lose.

I have looked closely at the space surrounding the part when its installed and can see room for any weld build up. Done skilfully/quickly by TIG welding the loss of hardness immediately adjacent to the weld should not be a problem.

Finding an a skilled and amenable welder is another matter! I seem to live in a black-hole area with very few local engineering companies. Its no use reminiscing but years ago one could always get little jobs done for beer tokens, nowadays with ISO 9000 or whatever, no one wants to bother.

Ian P

Ian P

Update...

I have made a new lever from solid out of EN24T (it was the only bit of decent steel I had) and having assembled and tested the Jigsaw it works!

I spent less than two hours to hacksaw the rough shape and then mill, drill and ream as required. I thickened up in some places compared to the original and also did not drill a couple of holes as they did not seem to serve any purpose, in fact the original part broke across on of the holes.

This part serves to push the blade forward on the cutting stroke, the so called pendulum action. I assumed that this lever was highly stressed and that was why Bosch had mad it very hard and tough. What I did not think about at the time was how the operating force was applied or transferred to the lever.

On examining the Jigsaw innards when I reassembled it I can see the oscillating arm that presses on the tail of the lever but I now realise that it must apply only a very small force as the witness mark on the lever is no more than a witness, its removed the blacking on the surface at the contact point but there is no detectable wear.. Its the tiny bright spot to the right of the hole (bottom right corner of the picture). The other bright area of the part is where the lever passes through a felt seal out of the gearbox casing.

Thanks for all the useful advice, comments and encouragements. I now have a fully functional machine again. I've not heat treated the part, I'm going to inspect it after a few hours of use but I suspect it will be OK as it is.

Ian P

Well done, Ian

Hewn from the solid ...

It looks much better than the original part.

MichaelG.

A bit late but I wondered if the part was cast. It reminds me of a part used in some Leitz Orthoplan microscope model's binocular head. Grain structure awful. That particular part seems to be cast steel or maybe iron. It too is rather hard.

John

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Ian, That is a brilliant job.

Bear..

Bear/Michael

Thanks for the compliments, it was pretty straightforward to make greatly helped by Bosch keeping to preferred sizes, ie, 4mm holes, 12mm centres, 12mm wide tab, 12mm between forks etc. There was only one dimension not in round numbers which was bottom hole centre 3.5mm from bottom edge.

Chopped out some disks of 12mm thick Delrin with the repaired jigsaw today, cuts beautifully.

Ian P