Myford ml7 chuck backplate.

[firebird]

Hi

The threads in my Myford ML7 chuck back plate are becoming quite worn so I bought a new one at the Warwick model engineering exhibition yesterday. The chuck is a 3 jaw self centreing Burnerd. I'm looking for some tips on the machining of the new backplate. I haven't removed the chuck from the old back plate yet. I have an adapter that fits in my rotary table that has a Myford thread on it. I'm thinking of centreing the rotary table in the mill so that when I have machined the register I can transfer it to the mill and drill the 3 holes for the mounting bolts. I should be able to get the PCD from the old back plate. Any thoughts or ideas would be helpful.

Cheers

Rich

 

[arnoldb]

Just a thought Rich - from a pretty inexperienced person...

The holes for the new backplate does not need extreme tolerances; they can in fact be a bit over sized. It is the register ring for the back of the chuck that is the most important and needs close tolerance...

Regards, Arnold

 

[John S]

Turn the backplate to get a snug fit on the register.
Get an Allen grub screw to fit the mounting hole in the back of the chuck, screw it it backwards so the cup part is just proud. Don't go too daft and loose it down t'hole.

Fit onto register, it will be tipped slightly but still have enough register to locate on.
Whack backplate with rubber hammer or copper bopper and a pad of rag inbetween.

This will leave a nice indentation in the backplate, centre and drill to the bolt size.

Refit to backplate with a bolt thru the hole into one of the other threaded holes, Whack the next position, drill and carry on.

John S.

 

[firebird]

Hi

Thanks Arnold and John

I got the register turned tonight to a good fit by sneaking up on it very slowly a few thou at a time. Just got to drill the the 3 holes for the mounting bolts now.

Cheers

Rich

 

[arnoldb]

Great ;D - how about a photo ? ;D

Regards, Arnold

 

[firebird]

Hi

I couldn't find any grub screws the right thread so I turned a piece of soft ally bar till it just pushed through the centre of the back plates then held the two back plates together face to face and drilled through using the old back plate as a drill guide. Its all bolted up and running again now.

Sorry Arnold I didn't think to take any photos. I don't want to unbolt it again to take any now its all fitted together and running well.

Cheers

Rich

 

[CrewCab]

I got the register turned tonight to a good fit by sneaking up on it very slowly a few thou at a time.

A year or so back I was terrified about fitting a new chuck ??? .......... there's a thread around where Ralph (Divided He ad) tries to reassure me .......... but it didn't work, I bottled out .....

.... anyway ......... a year and 3 new chucks later ...... ;D ........ it's not that hard, it's about confidence and Rich ........ IMHO .......... that's exactly the way to do it :bow:

as for the bolt holes, I turned three bolts to a point, parted off the heads, put them in the chuck and applied a little pressure ............ much as JS has described 8) ........... worked for me

CC