Gallery, Projects and General => How do I?? => Topic started by: PekkaNF on March 20, 2019, 03:13:37 PM

Title: Milling T-groves on
Post by: PekkaNF on March 20, 2019, 03:13:37 PM
I have some offcuts from cast part ends. Material is   EN-GJS-500-7 (GRP500)  Spheroidal graphite cast iron. Nominally it should be very nice material to machine. I have mixed experience with it. These are ends of the cast bosses and are cut off during manufacture. Some are porous at the very end, or are hardened. Some are pretty nice to turn, but milling seems to be a little harder.

Material number is 5.3200. Nominally  Brinell hardness (HBW): 150 - 230, but it feels harder than that.

I would like to mill T-groves to them and having a little trouble choosing to buy T-grove milling cutter. It should be good enough,butnot overly expensive.

I haven't tried it yet. One friend tried, made 10 mm slot witha a mill, but strugled to make T-slot.

I am looking proper size for M6 T-nuts. 10 mm groove, 15-16 mm wide bottom.

Suggestions? Easy or not?
Title: Re: Milling T-groves on
Post by: chipenter on March 20, 2019, 04:02:09 PM
As they are ends they may have chilled and become hard , anneal them first , I would make a cutter from silver steel and run it slowly .
Title: Re: Milling T-groves on
Post by: philf on March 20, 2019, 04:29:08 PM

I can't say I've tried to cut a T slot in spheroidal graphite but have cut quite a few in steel and aluminium.

I use a smaller roughing cutter - say 8mm to cut a slot slightly deeper than the bottom of the T slot, then open the slot to the correct 10mm width climb milling both sides.

Then cut the T slot. If I don't have the right size of cutter it's possible to have several bites at the slot because the shank above the cutter is usually a smaller diameter than the required T slot width.

ArcEuro have some very reasonably priced cutters: (

Title: Re: Milling T-groves on
Post by: PekkaNF on March 21, 2019, 12:34:46 PM
Thank you, Thank you Phil...those looks the part. I will concider them, just have to work out timing and P&P is killer - I usually order on same damage some more items on same go from ARC.
Title: Re: Milling T-groves on
Post by: PekkaNF on April 02, 2019, 03:19:22 PM
Got small order from Arc Eurotrade

I got those T-slot cutters. Not sure if those will do, they look pretty generic ones. Hope they are slighty better quality than e-bay norm (I will not buy any chinese HSS tools - never had any sucess with them - at best 10% quality of old russian tooling with 2x price).

Got lathe file as well (my third one...Finnish made "Viiala" still best, but I need a back-up).

Incidently, I have been reconsidering alternative way of making few jigs.