chuck backplate

[John Rudd]

I have an 80mm 4j chuck and need to make a back plate for it....

I intend to use 85mm dia CI, 25mm thick...


Any tips on the machining process before I make a complete cock up of it......?

[John Rudd]

The latest....

Well the backplate fits ok and I managed to drill it to take the chuck retaining bolts and tapped it thru M14*1....

Second phase was to machine a soft end arbor for it...Duly acquired from ArcEuro...I proceeded...

I realise this thread is a POC without photos.....I didnt take any..just as well because the whole job has been one complete nightmare......

Once assembled, the chuck srcewed onto the mores taper adapter has more than an acceptable level of runout

So its scrap...


Plan B is to get a 125 mm backplate for my 9*20 and modify that to take the small chucks.....

Laterz...

[andyf]

Just wondering, John - on the arbor, did you put a plain register section behind (and a bit bigger in OD than) the threaded section, with an even larger diameter shoulder behind the register? A plain section inside the backplate, bored to be a very good fit on the register, would do the locating when screwed on to butt up against the shoulder.

(He asked, being one who has never tried to make a backplate  )

Andy

[John Rudd]

Just wondering, John - on the arbor, did you put a plain register section behind (and a bit bigger in OD than) the threaded section, with an even larger diameter shoulder behind the register? A plain section inside the backplate, bored to be a very good fit on the register, would do the locating when screwed on to butt up against the shoulder.



Andy

Yes....did all that...In fact the register was 14mm on the arbor and a smidgen over on the backplate....

[fluxcored]

Hi John,

I'll have to go through the same pain soon. What's putting me off is that I have'nt got the correct change gears to cut the backplate's internal thread so that it can fit my spindle.

I'm scheming to fabricate the 32T change gear I need myself and am psyching myself  up to start on that since it'll most likely end in failure.

One step at a time.

Regards.

[John Rudd]

An update....

All done!

I took a premade backplate off my 125mm 4jaw chuck, machined it up to suit the recess of my little 80mm chuck.

Reduce the outer diameter and drill the back to suit the mounting holes....

A couple of piccies....which are crap I must confess....






Now I can get back to my steam engine which I'd like to build........

[CrewCab]

Sorry John, only just seen this thread though I'm surprised you didn't get any response to your original post, anyway I'm no great expert but having now done about 3 new backplates I've started each time with a Part machined RDG unit and they have all worked out fine.

CC