which bronze alloy should I have my parts cast from?

I am making a 2-part clamp for the quill of an old camelback drill press. The two parts together are about the size of the palm of my hand. I made patterns and they are at the foundry. I have been advised to avoid red brass (95-5-5-5 aka C83600) as it is relatively weak (14 ksi) and I don't want this part to break.

The next bronze they are pouring is C95400, an aluminum bronze with a machinability rating of 0.60 - what does that really mean? It is much stronger (21 ksi). I have to bore it, mill it and drill/tap 2 holes. The machine I have is a Bridgeport type mill from Spain.

Weldability is immaterial in my case.

I really need some help deciding what to choose.

metalmagpie

That brass (836) should be ok for a quill clamp unless you are planning to use a cheater on it. It casts well, it's a similar tensile strength to many cast irons and those wouldn't be out of place on the original. The aluminium bronze would be far stronger in tension, but probably wouldn't bee needed and may (or may not) cause you some difficulty in machiing.

Hi metalmagpie:
954 aluminum bronze is one of the better aluminum bronzes to machine but it's still a bit of a bitch to deep drill, to ream or to tap.
Turning and milling it is pretty easy by comparison.

I agree with Mark Rand that C954 is probably overkill, and brass will likely be plenty strong for the part you're describing.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

There are many others - but not necessarily at that foundry

I’ve been looking for someone to pour red brass. Seems the lead content is a problem. Would you share the name of the foundry that offered to pour the red brass? Do they do investments or sand or both?


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metalmagpie said:

I am making a 2-part clamp for the quill of an old camelback drill press. The two parts together are about the size of the palm of my hand. I made patterns and they are at the foundry. I have been advised to avoid red brass (95-5-5-5 aka C83600) as it is relatively weak (14 ksi) and I don't want this part to break.

The next bronze they are pouring is C95400, an aluminum bronze with a machinability rating of 0.60 - what does that really mean? It is much stronger (21 ksi). I have to bore it, mill it and drill/tap 2 holes. The machine I have is a Bridgeport type mill from Spain.

Weldability is immaterial in my case.

I really need some help deciding what to choose.

metalmagpie

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C83600 is for ornamental and decorative use. Prestigeous or historical building signage, plaques, nameplates, thread dial data plates. It takes and holds fine detail well, is weather and salt corrosion resistant "enough" to be used for some types of Brass fittings aboard ship. OK for plumbing fittings, too.

No Fine Way I would use it in any sort of "structural" or load-bearing application, though!

C95400, OTOH is great for gibs and clamping, stands up well to pressure and sliding wear, should last near-as-dammit "forever" as a gib/clamp.

Tapping is challenging, but folks who need to do JFDI every working day.

Read-up on that before you start, take heed. You should be OK.

adh2000 said:

I’ve been looking for someone to pour red brass. Seems the lead content is a problem. Would you share the name of the foundry that offered to pour the red brass? Do they do investments or sand or both?

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Gil's Aluminum on South Holden Street in Seattle, Washington, USA.

A very long way from the Aland Islands!

metalmagpie

If the clamp is too strong and it does not break will it break something else that is harder to replace? Decide why the original one broke first before deciding on what to make the new one from. Do not be like the shade tree mechanic who replaces a shear pin with a hardened steel one so it will not break so much.
Bill D

Mine isn't broken; it's missing. This stop collar is intended to be loosened and moved up and down the quill. In normal use the only strain on it is at most a pound. Some guys no doubt remove theirs entirely to get a bit more quill travel. My guess is that mine got lost.

I wonder if I should be considering having the part cast in iron. Cattail Foundry comes to mind, the Amish place in Pennsylvania. Of course, iron comes in many grades, and I don't know what they pour out there. But I've heard they are reasonably priced.

metalmagpie

metalmagpie said:

Mine isn't broken; it's missing. This stop collar is intended to be loosened and moved up and down the quill. In normal use the only strain on it is at most a pound. Some guys no doubt remove theirs entirely to get a bit more quill travel. My guess is that mine got lost.

I wonder if I should be considering having the part cast in iron. Cattail Foundry comes to mind, the Amish place in Pennsylvania. Of course, iron comes in many grades, and I don't know what they pour out there. But I've heard they are reasonably priced.

metalmagpie

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Cattail manages to cast THIN chimbly cleanout hatch covers, they'd HAVE to know their s**t.

"Cattail manages to cast THIN chimbly cleanout hatch covers, they'd HAVE to know their s**t."

But you dont know your s**t termite the troll...

Donie, do you really intend to poison every thread in which Thermite shows his face.
This is getting to be a real nuisance, and it's not helping anyone with anything.

Those who like Bill will continue to do so.
Those who hate Bill will continue to do so.
You're achieving NOTHING with this.

Now, I have seen both of you contribute useful things to this forum when it comes to answering machining related questions.
Sometimes it can be a bit difficult to pull out the goodies, but each of us has their own style, and I'm good with that.
Can you please PLEASE get back to that...I'll happily read all both of you have to say (and appreciatively take the useful bits) if you can just give up launching the big attack as soon as you see your opponent's name.

This is just a shitshow and most of us are getting sick of it.

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

implmex said:

Donie, do you really intend to poison every thread in which Thermite shows his face.
This is getting to be a real nuisance, and it's not helping anyone with anything.

Those who like Bill will continue to do so.
Those who hate Bill will continue to do so.
You're achieving NOTHING with this.

Now, I have seen both of you contribute useful things to this forum when it comes to answering machining related questions.
Sometimes it can be a bit difficult to pull out the goodies, but each of us has their own style, and I'm good with that.
Can you please PLEASE get back to that...I'll happily read all both of you have to say (and appreciatively take the useful bits) if you can just give up launching the big attack as soon as you see your opponent's name.

This is just a shitshow and most of us are getting sick of it.

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Click to expand...

Amen Marcus! I used to have thermite on ignore, but I gradually got used to him and his style of posting... And he actually (in translation) sometimes posts helpful advice. I don't remember anything from donie... and possibly because all of his recent posts are just vitriol and vile towards thermite?

Back on topic, OP says this part is approx the size of his palm. Am I missing why it would be cast in the first place? It's a locking collar, correct (or did I miss that? ).... make out of a solid piece, bore the hole, drill/tap and bandsaw in two pieces, belt sand the cut edges to desired finish/form and done...


McMaster-Carr ??

I am reproducing the original part. I am aware that I could make a functionally equivalent part more cheaply.

metalmagpie

Mike1974 said:

Back on topic, OP says this part is approx the size of his palm. Am I missing why it would be cast in the first place? It's a locking collar, correct (or did I miss that? ).... make out of a solid piece, bore the hole, drill/tap and bandsaw in two pieces, belt sand the cut edges to desired finish/form and done.

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Hi metalmagpie:
You want to make a reproduction part that looks as well as functions like the original.
To you that means casting it just like the original was done.
I get that, but have you considered machining it and then dressing it up to look like a casting?

I ask because the guys just below me (owners of the building) do classic and vintage car restoration.
Mike is their resident maker of unobtanium stuff; super nice guy and highly skilled at what he does.

He just showed me folding windscreen components for a 1920's? Rolls Royce that he's been making for a restoration job on the remains of that car.
He carved them out of 360 brass bar and they are frickin' BEAUTIFUL.
They look just like the castings they were patterned after, and they were carved with a bandsaw, a Bridgeport and a little pneumatic belt sander like automotive bodymen use.
He's used selective sandblasting with super coarse grit to mimic the texture in the places where the originals were not polished.

Once they're chromed, you'd never know how they were made, and the labour hours are no more than he would have spent to make patterns, cast them, fixture them and finish them.

Food for thought!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

implmex said:

Donie, do you really intend to poison every thread in which Thermite shows his face.

Click to expand...

you're not limited to putting just one person on ignore you know

I would do the 954. But that would not be period correct for your machine....
Drilling and tapping is not an issue if you use fresh tools....specifically a new tap for the threads.
Cheers Ross

implmex said:

He carved them out of 360 brass bar and they are frickin' BEAUTIFUL.
They look just like the castings they were patterned after, and they were carved with a bandsaw, a Bridgeport and a little pneumatic belt sander like automotive bodymen use.
He's used selective sandblasting with super coarse grit to mimic the texture in the places where the originals were not polished.

Click to expand...

I know a guy who does pseudo-antique stuff for motorcycles, he uses a needle scaler and the stuff comes out very authentic-looking. Very. To the point where he's had 'knowledgeable' bystanders come up and explain how his Sportster was built in the thirties

EmanuelGoldstein said:

I know a guy who does pseudo-antique stuff for motorcycles, he uses a needle scaler and the stuff comes out very authentic-looking. Very. To the point where he's had 'knowledgeable' bystanders come up and explain how his Sportster was built in the thirties

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ROFL! Chairman of our firm had bought two baroque period reproduction cast-brass framed then gilt French mirrors in Par-ee.

Each had bustid-off ONE of two 3mm-80 screws with a gilt knob and cap the mirror swiveled on. Told him no big deal, I had a lathe at home, we had gold-plating capability in the shop, I'd have a perfectly matched replacement for him in the morning. Got all UPPITY that it had to BE "perfect match".

Next day, handed him a pair for each, say: "OK. Tell me which is copy and which is original."

Screw-tin-eyes 'em with a jewelers loupe. "Damn, Bill. Thats GREAT work! I cannot tell them apart! Which one IS the original?"

"Neither."

"Here's the originals. Absolute shite. That's why they broke."

"The ones in your hand match because I made ALL FOUR out of better material and as studs, not screws, so the mirrors don't get broken, next go, even if the cap is screwed clear off!"

And that's how the clever old divil got me to make new flush fuel filler "keys" for his 75 foot Hatteras outta Nickel Aluminium Bronze and Bronze-rivetted real Rosewood to replace the shiddy-lookin' shiney-wood OEM ones!

Gotta have a bit of fun outta life. Turned down his generous invite for a cruise up the Chesapeake on that thirsty B**h.

Manhattanite-generous. Of one-time Russian "minority" he was as a host.

Folks who had the pleasure were expected to chip in for the fuel, and he loved keeping her twin 12V something-or-others at full-gallop!

Fair man, though. Scored more points for good judgement with his "frugal" ass turning him down than had I taken up the offer!