Copper vs aluminum jaw spacers?

[GL]

As I watch the usual YouTube suspects, there seems to be a preference for making “soft jaw” spacers from copper. The main purpose is to keep from marring a machined surface with the serrations of the chuck jaws. Aluminum cans have a very controlled thickness, but seem to not be thick enough, at least from a durability standpoint (although they are cheap and easy to make). Copper tube can be flattened after annealing easily. Dealing with separate pieces can be annoying at times. Copper and aluminum are both soft enough to protect parts and available in thick enough sheets to make the more permanent snap on or screwed down versions we see frequently. Copper is significantly more expensive. Does copper actually perform better or has it just become convention?

Thanks.. Be safe..

 

[Rich Carlstedt]

My copper jaws are maybe 50 years old , they really stand up
I also have aluminum jaws that i made from bar stock.
The thing I like about copper is that no matter how hard I clamp, it does not distort the copper
and I never see impregnation of copper in the work piece . With aluminum , the jaws distort and wrinkle
With thin sheet Aluminum ( I gave up ) , I got particle of aluminum impacting (?) the work piece leaving residue
I shifted to solid bar ( 3/4 x 2 x 5) and milled out pockets for the jaws so it will sit on the jaws
Now here is the rub. I do a bit of silver soldering, and any aluminum residue will affect flow quality of silver solder ( very bad)
Copper on the other hand never transfers over to the part and so is much more accommodating.
I also believe ( maybe the softness ?) that the copper grips the work better than aluminum ( my opinion) , but when
I have aluminum parts, I like the aluminum jaws !
You should know that I have multiple jaws for my vise---, steel, copper, aluminum and plastic, but the favorite is copper as
seen here griping a collet holder
Rich

Worked for a can producer, and you are right the walls are a very uniform .004" (.1mm)

 

[Eddyde]

I use sheet copper and aluminum to make protective pads for finish work, as I need them. Aluminum wire works well for clamping uneven or slightly out of parallel parts in the mill vise, as it crushes and conforms to the profile.

 

[David2011]

Thanks, Rich. That was very insightful.

 

[GL]

Thanks for the insight. The original intent of the question was for spacers in a lathe chuck, but the information given works for vice jaws or any other gripping activity. Never would have thought about material transfer or how it might affect later processes. I have done minimal silver soldering but based on Blondihacks boiler/steam engine videos, it seems to be susceptible to any number of ways to do it wrong.
Other searching seems to point to making special sleeves or packing spacers out of aluminum or whatever as required, as essentially a one use item. The durability question becomes moot at that point. Copper seems like a better and more permanent solution.

 

[Parlo]

Don't make the rod type inserted soft jaw spacers, they concentrate the load onto a single line instead of spreading the clamping pressure over a larger area. I have found that annealing Copper makes a huge difference but prefer Aluminium.

 

[verbotenwhisky]

As I watch the usual YouTube suspects, there seems to be a preference for making “soft jaw” spacers from copper. The main purpose is to keep from marring a machined surface with the serrations of the chuck jaws. Aluminum cans have a very controlled thickness, but seem to not be thick enough, at least from a durability standpoint (although they are cheap and easy to make). Copper tube can be flattened after annealing easily. Dealing with separate pieces can be annoying at times. Copper and aluminum are both soft enough to protect parts and available in thick enough sheets to make the more permanent snap on or screwed down versions we see frequently. Copper is significantly more expensive. Does copper actually perform better or has it just become convention?

Thanks.. Be safe..

I machined a set of jaws to bolt onto my vise in place of the original steel jaws and they work well, hard enough to hold and soft enough not to be marring....

 

[verbotenwhisky]

Thanks for the insight. The original intent of the question was for spacers in a lathe chuck, but the information given works for vice jaws or any other gripping activity. Never would have thought about material transfer or how it might affect later processes. I have done minimal silver soldering but based on Blondihacks boiler/steam engine videos, it seems to be susceptible to any number of ways to do it wrong.
Other searching seems to point to making special sleeves or packing spacers out of aluminum or whatever as required, as essentially a one use item. The durability question becomes moot at that point. Copper seems like a better and more permanent solution.

I get seamed copper water pipe and cut and split it and put it over my lathe chuck, works well.