Author Topic: Gun metal v Phospher bronze  (Read 5279 times)

Online crueby

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Re: Gun metal v Phospher bronze
« Reply #15 on: February 11, 2018, 02:31:14 PM »
Thats all why I stay clear of C260 brass whenever possible, favoring 360, also find the 932 bronze much better for machining and drilling.

Offline Ramon

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Re: Gun metal v Phospher bronze
« Reply #16 on: February 11, 2018, 04:43:55 PM »
Hi,  I have sometimes found drilling various "brasses' difficult with grabbing etc etc but put it down to " a bad workman blames his tools" !! Now i can say " A good workman blames his tool suppliers for not making the correct type of drills for specifically drilling various type of brasses without mishap" !!!! ;D So how does the Industry cope ??  !!

Hi Willy,

I can't comment for nowadays as things have moved on so much but 'in my day' exactly as above if correct drills weren't available other than the normal jobbers drills. Stoning the edge off was common practice for 'brasses' but as for Drawn PB well Chris has it about right - I avoid using it when I can but there are times I prefer to use it as in this valve and on conrod lower end bearings in my diesels

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Jasonb

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Re: Gun metal v Phospher bronze
« Reply #17 on: February 11, 2018, 05:55:03 PM »
Willy, you can buy "slow spiral" drills for just this sort of thing, the steeper angle of the flute reduces the "top rake" of the cutting edge Much like stoning the edge.

Probably not needed by industry now as the drill is fed by CNC so won't get pulled like a slack tailstock. When opening up brass and bronze hole son teh mill I feed the head down rather than use the quill wish I had done the same with that valve gland.

High Helix (fast spiral)are also made as well

Offline petertha

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Re: Gun metal v Phospher bronze
« Reply #18 on: February 14, 2018, 06:01:00 AM »
Subsequent to my post, I too have been experimenting. My grabby problems are definitely exaggerated on larger diameter drills to where they can become planted or wreak havoc with the tailstock chuck/MT arbor. I also realized under magnification that my 'new' HSS drills are razor sharp & have an ever so slight curve on the lip. some kind of funky grind (still a 118-deg point). They are well made, cut steel like a damn, but just asking for trouble in the 'B' materials.

I took a 0.375" drill & did a test hole in my C932/SAE 660 bronze, 544 bronze and C360 free machining brass. That was also the order of 'grabbiness'. I then dubbed the same drill like what is shown in Clickspring video. Nothing else changed. Same spot drill, same speed & feed. And the difference was like night & day. It just walked into the material like it was a completely different alloy. I felt like a small miracle had occurred. So I dedicated some larger progressive drills to this dubbing treatment & I am going to get a set of reasonably priced HSS, dub them all & leave them reserved for this type of material.

Online Vixen

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Re: Gun metal v Phospher bronze
« Reply #19 on: February 14, 2018, 11:31:24 AM »
I then dubbed the same drill like what is shown in Clickspring video. Nothing else changed. Same spot drill, same speed & feed. And the difference was like night & day. It just walked into the material like it was a completely different alloy. I felt like a small miracle had occurred. So I dedicated some larger progressive drills to this dubbing treatment & I am going to get a set of reasonably priced HSS, dub them all & leave them reserved for this type of material.
Hi petertha
Is there a link to the Clickspring video somewhere (or did I miss it)?  :noidea:

Thanks for sharing

Mike
It is the journey that matters, not the destination

Offline Jasonb

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Re: Gun metal v Phospher bronze
« Reply #20 on: February 14, 2018, 12:31:15 PM »