How do i machine this ( on the wonk)

I have this part that i want to replicate

The shaft to the left is concentric to the middle boss but the boss is 18mm on one side and 19.3mm on the other making the shaft to the right at a shallow angle.

how can i do this?

How about turning the concentric areas in a 3 jaw, and then hold the long spindle in a four jaw to offset the right hand end for the thread cutting etc?

Howard

Well its not eccentric its bent

Make a bush, but drill or bore it in the milling machine to the required angle. You could either set the mill head over to the angle or rig some sort of sine table arrangement.

Then machine one end of the part, hold in the wonky bush (grubscrew perhaps) with the bush held in 4 jaw chuck to machine the second end.

You still have the problem of getting the intersection of the two wonky axes in the right axial position. A bit more examination of the part needed to determine where and how important it is and how the OEM did it.

Martin

Get am excess length of stock and cut a couple of inches off. Turn the part on the left that is square to the large diameter. Drill / bore the excess stock at the correct angle to take the turned end. Then either slit it and hold in chuck. Alternatively loctite / glue / soft-solder it into the drilled part and chuck it. Now you can turn the angled end.

Martin types faster...

Brilliant thanks to martin and robert

On a lathe, ER collet block bolted to an angle plate bolted to the faceplate.

Make it out of two pieces silver soldered together, the joint on the RH end of the 35mm dia. part. It is easier to set up in the mill to bore an angled hole the receive the threaded part

Martin Johnson 1 has the right idea, why are people talking about making in 2 pieces?

Tony

Between centres.

You need two centres in each end, in waste material, that'll keep the two ends in the correct position.

The offsets can be calculated or use a drawing, they'll be different for each end depending on where you want the intersection of the two halves to be.

One pair does the first bit the other pair do the other.

Steve

You need a lathe with a curved bed

Well i bodged it

turned the lot as one screw cut the threads and then cut with the bandsaw (1mm kerf) about 3/4 the way through the 35mm boss then squeezed it in the vice and welded it up

measures as well as my original

Its for a belt grinder the tracking adjustment for the pulley

I didn't want to say "weld it" because that's talking dirty

Funnily enough I once bought a 4-jaw chuck from a man on Ebay which would probably have made a breeze of this job. The swine.

..Anyway, just out of interest, what's the make of the grinder? - it seems like a bit of a complicated manufacturing solution to a simple problem.

The original shaft is from a Robert sorby proedge

its a very elegant way of tracking the belt

Ah, now you say it, it makes sense - I was just interested because it's rare to see a production part these days where other factors have influenced the design over just plain 'cheapness'..

I just realized there is an easier way.

Turn a bush to fit end a so part fits to the face of the bush.. Remove from chuck.

Grip the old part in chuck by end b. Mount the bush on end a, turn exterior of bush parallel.

You now have a wonky bush with correct throw, and a datum face to plant a part finished blank completed up to end a.

Grip bush and part finished part in chuck to finish end b.

No mill required.

Martin

Perhaps not that elegant? The ProEdge requires the use of two Tommy bars to adjust the tracking whilst Axminsters Ultimate Edge just uses a single knob.

Vic

i can see that the Axminster one just has a knob…do you know how that works? Is it on a hinged spindle to adjust tracking? The sorby one whilst needing the tommy bars once set I’ve never adjusted it in all the time I’ve had it perhaps 7 years or so with many hundreds of belt swaps and new belts.

this is my finished machine for use in my metal working room…the genuine one is by my woodturning lathes

Oh and Martin j many thanks for that suggestion on how to make the bush..i was going to use your idea if my part didn’t work however it seems fine so far