Been a bit slow here in the past several days and so thought some might enjoy seeing parts of a little job i have been running on my 3150 RPM FP4NC.
Had an OSCA MT4 in the shop and part of the needed work was replacement of the brake drums...
The OSCA uses an aluminum housing on the drums, finned and fitted with an iron friction liner. Did a bit of looking and nothing use able was available that fit the requirements.
So i set out to reproduce the originals....Measurements taken and sketches made of the relevant parts of the drums.
Good news here is that all 4 drums are the same, same offset , diameter and width...so only one design needed....
Outer body of the drum was made form aluminum. Originals were cast with the iron liner cast in place....Not an option here.
I choose to make the iron liners be shrink fit into the aluminum outer, and to be sure things stay put i joined the liner to the drum using a "spline" to assure a positive "anti-turn" result.....
Liners were blanked out from a Ford Taurus brake drum form the local Napa auto parts house.....
Once blanked out (boring lathe work) the liners were setup on the Deckel and held via the same chuck that i used tor the turning work.
Here the "Pie" jaws support the part (thin) without changing its shape.....
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One of the nice things about having "D" style chucks is that by simply removing the cam lock pins (takes about a minute) you can easily set the chuck on the true face of the chuck adapter...
nice for mill work .
Here i use a simple through bolt to the table "T"... Tighten the chuck on the part. lightly , check to see if the part is flat, then secure the chuck grip, finally tighten the center bolt....
Program for the spline was worked out in SurfCam...this is a smooth curve spline...internal and external curves all the same....no sharp edges.
Cut begins. Overall height of the spline will be at .2" taken in two passes for full depth.
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Final on the spline.....
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Close view of finished spline...
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More to follow
Cheers Ross
Had an OSCA MT4 in the shop and part of the needed work was replacement of the brake drums...
The OSCA uses an aluminum housing on the drums, finned and fitted with an iron friction liner. Did a bit of looking and nothing use able was available that fit the requirements.
So i set out to reproduce the originals....Measurements taken and sketches made of the relevant parts of the drums.
Good news here is that all 4 drums are the same, same offset , diameter and width...so only one design needed....
Outer body of the drum was made form aluminum. Originals were cast with the iron liner cast in place....Not an option here.
I choose to make the iron liners be shrink fit into the aluminum outer, and to be sure things stay put i joined the liner to the drum using a "spline" to assure a positive "anti-turn" result.....
Liners were blanked out from a Ford Taurus brake drum form the local Napa auto parts house.....
Once blanked out (boring lathe work) the liners were setup on the Deckel and held via the same chuck that i used tor the turning work.
Here the "Pie" jaws support the part (thin) without changing its shape.....
One of the nice things about having "D" style chucks is that by simply removing the cam lock pins (takes about a minute) you can easily set the chuck on the true face of the chuck adapter...
nice for mill work .
Here i use a simple through bolt to the table "T"... Tighten the chuck on the part. lightly , check to see if the part is flat, then secure the chuck grip, finally tighten the center bolt....
Program for the spline was worked out in SurfCam...this is a smooth curve spline...internal and external curves all the same....no sharp edges.
Cut begins. Overall height of the spline will be at .2" taken in two passes for full depth.
Final on the spline.....
Close view of finished spline...
More to follow
Cheers Ross