Switching over to D1-4 Chuck back plates

CH, as mksj mentions in post no. 3, could you take a skim cut on the 'loose' backplate to improve the fit?
 
If you are talking about the fit of the chuck to the back plate of the zero-set registration these will fit loosely with about 0.005" clearance to allow the zero-set screws to have enough adjustment to true up the chuck. In addition, some people leave 1-2 thousandth clearance between the registration step and the chuck body in non-zero-set (Set-Tru) chucks to allow one to tap the chuck into final alignment before tightening the mounting bolts. As mentioned, I mount the backplate to the lathe and check it for any runout. With inexpensive backplates I typically need to take both a skim and a registration cut, I would use either sharp HSS or ground edge insert to get a clean cut.

The Gator backplates run around $160 for their 8" (Ajax Industries), but are very well finished. Shar's and Grizzly Tools sell them for less but sometimes get you in the shipping rates.
 
Tozguy said:
CH, as mksj mentions in post no. 3, could you take a skim cut on the 'loose' backplate to improve the fit?
Click to expand...
I guess i was not clear about fitting. The back plate seat all the way to the face with just a light pressure, like the tapper is oversize. The back plate the came with the lathe is tighter and needs help from the cam locks to fit with no gap at the spindle back plate matting surface. The back plate from Shars just about falls off when the cam locks are opened, and back plate just easily slides off the spindle.
Does that make sense?
Thanks for the sujestion.
CH
mksj said:
If you are talking about the fit of the chuck to the back plate of the zero-set registration these will fit loosely with about 0.005" clearance to allow the zero-set screws to have enough adjustment to true up the chuck. In addition, some people leave 1-2 thousandth clearance between the registration step and the chuck body in non-zero-set (Set-Tru) chucks to allow one to tap the chuck into final alignment before tightening the mounting bolts. As mentioned, I mount the backplate to the lathe and check it for any runout. With inexpensive backplates I typically need to take both a skim and a registration cut, I would use either sharp HSS or ground edge insert to get a clean cut.

The Gator backplates run around $160 for their 8" (Ajax Industries), but are very well finished. Shar's and Grizzly Tools sell them for less but sometimes get you in the shipping rates.
Click to expand...
Hi Mark
I went to Ajax Ind. site didn’t see any D1-4 back plates for 8” chucks for under $300 +. I searched for a Gator D1-4 back plate but only Bison was listed. Do you have a direct link to the Gator back plate?
Thank CH
 
I would recommend calling Ajax Industries, I can't find anything on their site and for that matter Google searches with part numbers are useless these days so I am back to calling around. You may need to get the semi-finished and cut the registration, I would check the dimensions against your chuck.
FLD-200D4: Machined for Plain Back Scroll
http://www.gts-tools.com/catalog/products.php?id=FLD-200D4&cid=d-gab-a-pbsc

FL-200D4: Semi-Finished for Plain Back Independent & Scroll Chucks
http://www.gts-tools.com/catalog/products.php?id=FL-200D4&cid=d-gab-a-pbisc

All my backplates easily come off the spindle nose, no tapping or gyrations. As long as it goes on/off and you can repeat the TIR to be ~same then I would be OK. Also, one always needs to carefully clean both mating surfaced before mounting. I lightly torques the three D pins and then go around again to tighten fully.
 
COMachinist said:
I guess i was not clear about fitting. The back plate seat all the way to the face with just a light pressure, like the tapper is oversize. The back plate from Shars just about falls off when the cam locks are opened, and back plate just easily slides off the spindle.
Click to expand...

If the face of the backplate is cut slightly (faced) then the taper will go a bit deeper and fit tighter on the spindle.

Maybe that's what Mark is referring to when he writes ''With inexpensive backplates I typically need to take both a skim and a registration cut''
 
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ok I think I understand now I got the lathe on the stand today and this is what it looks like when just push the back plate on.
Thanks for all the help.
CH

HPIM0582.jpg

HPIM0586.jpg
 
Well I did a skim cut on the back plates and mounted the chucks the the spindle and back plates have less than a 10th TIR. When I mount the scroll chucks they are under the .002 which I guess is not bad for cheeper chucks my Bison 3 jaw is around 1.5 thou that works for me, i have a new D1-4 independant 4 jaw, I’m going to do a check on head stock alignment using the Rollie’s Dad methood then I cant get serious.
Thanks all
CH
 
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