Bronze machining speed.

[Nick_GParticipant @nick_g]

[Nick_GParticipant @nick_g]

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I have a piece of bronze 4 1/2 in diameter.

What sort of spindle speed and feed rate should I be using with a HSS tool as a starting point.

I ideally would wish to keep a much mass in it as possible so really want to machine off as little as practical. Hence do not really want to be carving off any more than I have to 'experimenting'

Cheers, Nick

[Jim CParticipant @jimc]

Hi Nick,

Just done the calcs and come up with 169 rpm. Anywhere near what you were thinking?

Jim.

[Nick_GParticipant @nick_g]

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Thanks for that Jim,

TBH I have no idea.

Cheers, Nick

[Thor 🇳🇴Participant @thor]

Hi Nick,

There is a nice online calculator here, with suggested cutting speeds in Feet/Min. both for HSS and carbide tools.

Thor

Edited By Thor on 30/03/2016 17:57:23

[JasonBModerator @jasonb]

Those that have been members for a long time will know I'm not really one for calculating feeds and speeds but as Nick is a new boy here he does not need to know that so I did a few rough calculations.

Starting with the date that gave me 30, I then multiplied by the number of toes I have (full set) 10 which gave me 300 but had second thoughts which gave me a 2 so multiplied by that as well and got 600rpm.

I still have the offcut from my Hoglet flywheel so stuck it on the chuck and cleaned up the cast surface with a CCGT tipped tool to get a clean start to try the HSS on.Taking a couple of light 0.010" deep cuts as Nick is not worth wasting more bronze on and besides he said he only wanted to skim a little off. Came out like this at 600rpm which is not too shabby.

I then tried some HSS started at 600rpm, stopped the feed and twiddled my knob down to 300rpm and cut a bit more, stopped and twiddled to 160 and cut a bit more. I know what tool and speed I would be going with

Probably could have faffed about tweaking the HSS tool geometry but would have had the job done in less time than that would take with the CCGT.

J. Just having a bit of fun

[Nick_GParticipant @nick_g]

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Thank you most muchly Jason.

Although I should really be annoyed with you, as I have because of your post had to now buy some CCGT tips.

Nick

[Jim CParticipant @jimc]

Hey Jason,

Got some lazy apprentices at college that might find your formula for speed much more interesting than the heavy one I try to get them to use.

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