# Machining stainless steel at home? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [January 8, 2021, 10:53pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072 "2021-01-08T22:53:11Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 8, 2021, 10:53pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/1 "2021-01-08T22:53:11Z")
I have a stainless steel\* split shaft collar type item that needs to be embiggened. Its inner bore is 1.25" now, but I need to increase it to 1.35" and the thing is 0.6" thick. As a one-off thing, am I insane for thinking I could do it a half-round file, or can I put a 1.25" sanding drum with an appropriate abrasive in my drill press and wobble the thing around to make the hole larger? Or a cylindrical grinding stone? The ID is not concentric to the OD, so just chucking the thing on a lathe to buzz off that tenth is not happening. \*No idea what grade, probably 304. Not magnetic. ---
**Author:** ![MrMrmrmr](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrmrmrmr/32/5828_2.png) [@MrMrmrmr](https://boards.straightdope.com/u/MrMrmrmr)\ **Post date:** [January 8, 2021, 11:13pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/2 "2021-01-08T23:13:07Z")
You could try the file, see if it bites into the SS. If I’d does you should scribe a circle of the final size so you can file like a madman during the roughing phase, and slow down and use more care as you approach the final size. There is a reason we called it “Fuckin’ Stainless” when we had to work with it in the machine shop. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [January 8, 2021, 11:27pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/3 "2021-01-08T23:27:50Z")
It’s a split collar so you just need that to be tight on the shaft, you don’t need a perfect bore, right? Try the file, it’s going to take a while though. A carbide burr bit in your drill press might help remove some material quickly to start with, not sure what kind of speed that requires. A sanding drum will probably take longer but be easier to control. It’s really about how much patience you have. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [January 9, 2021, 12:33am UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/4 "2021-01-09T00:33:08Z")
Moving this to IMHO. It could potentially live in general questions, but i think a lot of the answers you might get will be people’s personal experience with similar situations, so i think this is the best home. ---
**Author:** ![MrMrmrmr](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrmrmrmr/32/5828_2.png) [@MrMrmrmr](https://boards.straightdope.com/u/MrMrmrmr)\ **Post date:** [January 9, 2021, 1:04am UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/5 "2021-01-09T01:04:11Z")
We made molds for the lenses in pinball machines out of 420 stainless. We had to drill 1/16” holes in two inch thick blocks to serve as start holes for the WEDM, wire electrical discharge machine. Stainless will work harden in a heartbeat if your cutter is rubbing. When you stop making chips you stop tool pressure and sharpen or replace the cutter. I hope you have a bench vise on a sturdy workbench because a rigid set up is also key to machining stainless. ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [January 11, 2021, 3:09am UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/6 "2021-01-11T03:09:30Z")
> [@gotpasswords](#): > > The ID is not concentric to the OD, so just chucking the thing on a lathe to buzz off that tenth is not happening. That is what the 4 jaw chuck is for. Get to a lathe. The 4 jaw will center it up. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [January 11, 2021, 12:52pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/7 "2021-01-11T12:52:23Z")
> [@gotpasswords](#): > > can I put a 1.25" sanding drum with an appropriate abrasive in my drill press and wobble the thing around to make the hole larger? Or a cylindrical grinding stone? If you’ve got a cutter/grinder that’s anywhere close to the ID of your shaft, and spinning at any appreciable speed, and you don’t have your part firmly fixed, there’s a risk that your part could start whirling violently around the cutter. OTOH, shaving off that much stainless using hand tools is going to be a mind- and hand-numbing process. Maybe you can find a local machine shop, and pay them to do it on a four-jaw lathe? Might cost you an hour of their time, so maybe $100. It might be worth that to avoid what would surely be a painful DIY job. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [January 11, 2021, 1:17pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/8 "2021-01-11T13:17:23Z")
I hope they would be nicer than that. 100 thousandths? A good machinist would have this part in the 4-jaw chuck, dialed in, bored, and deburred in about 10 minutes. I guess a job shop probably works like a auto repair shop, rounding up to full hours, but it seems like if you catch the guy on a good day it wouldn’t cost all that. Got any friends with a metal lathe? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 12, 2021, 9:06pm UTC](https://boards.straightdope.com/t/machining-stainless-steel-at-home/930072/9 "2021-01-12T21:06:03Z")
Follow-up I picked up a cylindrical carbide burr and on one half, I was able to raise the drill press table and swing the thing around to chew out most of what I needed. I just ran a red Sharpie along the edge so I could keep track of progress. Dummy me, I forgot to mention that the other half has a permanently attached rod along the axis, complicating things. I wound up clamping the rod in a bench vise and using the burr in a drill. Think that actually worked better than the drill press. Then some work with a small sanding drum in a Dremel to smooth out the bumps, and Bob’s yer uncle! Would I want to do this again? Oh heck no! But at $11 for a burr and some time, I got what I needed. And probably faster than calling around with “Hey, I got this chunk of stainless…” and getting into a shop’s schedule.