Hey all, first post here, but need a bit of advice. My shop recently quoted a part that should really be on a cylindrical grinder (Tight tolerance bores, concentricity, and true positions) as a mill job, simply because they could only find the stock in plate form. So now I've got these parts to make, and I'm racking my brain as to how to do it. I've only been in Machining for 2-3 years and could really use some tips. Here's what I know-
my parts are shaped like bushings with hats, (Probably not allowed to share details and specs, you know- Top secret stuff) .228 thick, about 1.750 in diameter. My stock is some 4340 aircraft grade steel, arriving in plate form, 12x6x.25. My only forms of workholding are a 6 inch vise and some clamps, but I have no subplate.
I was originally planning to cut the stock into 2x6 inch strips and roughing the bottom hat, then holding them in softjaws in the second op.
The biggest issue I'm having, however, is figuing out how to get an 8 RA surface finish on the part. I've never seen an 8 RA finish on a VMC, let alone on an Okuma Genos m560, in steel, no less. I've only got 50 parts to do, but I feel like my tooling costs are going to be at least 2k or something. I have a lot of ER32 collet holders and a few nominal set screw holders for weldon shanks, along with two .75 milling chucks.
It's a lot to ask, but please help a new guy out. I've looked into some grinding bits for the mill, but most can only get a max of 12 RA from what I've seen.
my parts are shaped like bushings with hats, (Probably not allowed to share details and specs, you know- Top secret stuff) .228 thick, about 1.750 in diameter. My stock is some 4340 aircraft grade steel, arriving in plate form, 12x6x.25. My only forms of workholding are a 6 inch vise and some clamps, but I have no subplate.
I was originally planning to cut the stock into 2x6 inch strips and roughing the bottom hat, then holding them in softjaws in the second op.
The biggest issue I'm having, however, is figuing out how to get an 8 RA surface finish on the part. I've never seen an 8 RA finish on a VMC, let alone on an Okuma Genos m560, in steel, no less. I've only got 50 parts to do, but I feel like my tooling costs are going to be at least 2k or something. I have a lot of ER32 collet holders and a few nominal set screw holders for weldon shanks, along with two .75 milling chucks.
It's a lot to ask, but please help a new guy out. I've looked into some grinding bits for the mill, but most can only get a max of 12 RA from what I've seen.