How can I mill down high speed steel?

I found some high speed steel (hss) that is slightly too large for my needs. The rod is 4.2mm and I need approximately 4.15mm.

It's going into some relatively soft plastic to it's not super critical that it's exactly 4.15mm. how can I mill it down? I don't have a lathe but I do have a drill press and sand paper. Would that even work or am I an idiot for considering it?

$8 Utoolmart Round Steel Rod, 4.2mm HSS Lathe Bar Stock Tool 100mm Long, for Shaft Gear Drill Lathes Boring Machine Turning Miniature Axle, Cylindrical Pin DIY Craft Tool, 5pcs

https://www.amazon.com/dp/B082GVX4TM/ref=cm_sw_r_cp_apa_fabc_UUq6FbV56W0QV

 

Why not drill out the plastic to the appropriate size?

 

The plastic parts get replaced regularly. I'd prefer to not need to modify the plastic parts every time one gets replaced. I'll do it if there is no other option.

 

Then you'll have to find a local machine shop.

 

Roll Tide and screw the Suckeyes (and ND)!

Sorry, back to your regularly scheduled thread.

 

No access to a lathe, then set it aside spend $4.26 + shipping at McMaster and buy the size you need. You send it to a machine shop to knock .002" it's gonna cost way more than the price of material to size.


https://www.mcmaster.com/8893K166-88645K51/

 

If the tolerance isn't super critical and the duty is for something personal then I personally would just do as you mentioned, sand paper in a drill press (carefully!) but you're taking about a .05mm tolerance that's pretty exacting...

Either order to spec or get it machined if it's that specific.

What is this rod's purpose?

 

For reference .05mm is .002". If you turn it on a lathe you're only moving the cross tool holder .001". Kinda tight tolerance.

Buy the rod to size from McMaster. Problem solved.

 

I already looked and couldn't find the size on MC

 

Hinge pins on an rc car

 

Where are you located?

 

For the A arms? if that's the case then yeah I wouldn't hesitate to chuck it up in a drill and sand it down till it fit. That said the A arms should be either injected ABS reinforced with fiberglass or similar and therefore relatively strong it probably wouldn't hurt them too much to drill them out either.

 

Northern va

 

The size in the link is .164". That's 4.16mm.

 

Think you could get away with a drill blank? #20 = .161 and #19 = .166. MC or Granger might have that size as a drill blank. If it’s short piece you need, you might be able to cut the shank off from the bit and use that.