How Would You Do This

[Rick_B]

I'm working on a table insert for an oscillating spindle sander. Material is mild steel - the basic shape was done on a water jet. I have faced off the surface to get the required thickness. Now I need to waste out material on the back side to leave a 3/8 wide rim.



Don't worry about the sloped surface in the center or the little plugs/protrusions. I'm not sure how to waste out the material from the edge of the rim to the center oval cut out - its roughly 3/32 that I need to remove. I'm using a 4 jaw chuck with the jaws reversed to hold it. Is what I am trying to do simply a facing cut? How do I achieve that nice square shoulder?
Thanks
Rick

 

[pontiac428]

Can you chuck it up internally on the ridge of the outer rim? That would allow a facing cut. A mag chuck would let you do it on the mill, or you could bore a stepped fixture plate with a sized circular relief and mill it that way.

 

[ChazzC]

My spindle sander has plastic inserts for thr different spindles(; I know you already save $$ invested in this part, but 3D printing would seem to be the best solution.

 

[Rick_B]

Can you chuck it up internally on the ridge of the outer rim? That would allow a facing cut. A mag chuck would let you do it on the mill, or you could bore a stepped fixture plate with a sized circular relief and mill it that way.

I currently have the jaws reversed and am holding the work piece on the OD. The wor piece is shimmed above the jaw surface and I used a facing cut to get down to the right thickness. I could use a facing cut to generate the relief but I'm not sure how to orient the tool to get the shoulder cut
Rick

 

[Rick_B]

My spindle sander has plastic inserts for thr different spindles(; I know you already save $$ invested in this part, but 3D printing would seem to be the best solution.

I'm looking to stay original if I can. If I was going to deviate I would probably try wood
Rick

 

[RandallsRaceShop]

I currently have the jaws reversed and am holding the work piece on the OD. The wor piece is shimmed above the jaw surface and I used a facing cut to get down to the right thickness. I could use a facing cut to generate the relief but I'm not sure how to orient the tool to get the shoulder cut
Rick

If you're going to face cut the material out, on the lathe in a 4 jaw, you could cut the shoulder with a boring bar.?.?.?

 

[Rick_B]

If you're going to face cut the material out, on the lathe in a 4 jaw, you could cut the shoulder with a boring bar.?.?.?

I like that idea - thanks
Rick

 

[Eddyde]

Or use a turning/facing tool, work from the center outwards.

 

[Rick_B]

I ended up just facing out close to the rim and finishing up with a boring bar



You'll notice a variation in the rim width - that is a result of not checking run out when I put the piece back in the chuck. I could correct that but that width is not a critical element.

Now I need to figure out how to put the sloped surface on the oval section. I believe the only option is hand work as /Wally suggested. Wally you said you used a grinder - like a 4-1/2 hand held grinder? I put some bluing on it so I could scribe the 1/4" or so depth of the slope.

Rick