I bought some ebonite rod, that I have turned on the lathe (for an art project).
It took the shape well, but I can not get it to polish.
The surface is hairy, yellowish, and pitted.
I lowered the feed rate, so the tool could cut and burnish, but that wasn't much better.

What is the standard method to turn then polish ebonite?

FWIW, I contacted the supplier (a pipe stem supplier), and he said that I can not mass finish hard rubber.  My desire would to be to finish the parts (like chess pieces) in some sort of automatic process.  I have a buffer, and ZAM was OK, but crappy, and Tripoli wasn't much better.

Any help would be appreciated.

Always a problem, for which I cannot offer a solution. You might try increasingly fine grades of wet and dry. Delrin looks similar and machines well.

Tony F.

 

From: MouthpieceWork@yahoogroups.com [mailto:MouthpieceWork@yahoogroups.com] On Behalf Of anchornm@...
Sent: Sunday, 15 December 2013 12:21 PM
To: MouthpieceWork@yahoogroups.com
Subject: [MouthpieceWork] Finishing ebonite

 

  

I bought some ebonite rod, that I have turned on the lathe (for an art project).
It took the shape well, but I can not get it to polish.
The surface is hairy, yellowish, and pitted.
I lowered the feed rate, so the tool could cut and burnish, but that wasn't much better.

What is the standard method to turn then polish ebonite?

FWIW, I contacted the supplier (a pipe stem supplier), and he said that I can not mass finish hard rubber.  My desire would to be to finish the parts (like chess pieces) in some sort of automatic process.  I have a buffer, and ZAM was OK, but crappy, and Tripoli wasn't much better.

Any help would be appreciated.





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This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

Heat build up is the enemy.





On Saturday, December 14, 2013 10:24 PM, Tony Fairbridge <tfairbri@...> wrote:
 
  
Always a problem, for which I cannot offer a solution. You might try increasingly fine grades of wet and dry. Delrin looks similar and machines well.
Tony F.
 
From:MouthpieceWork@yahoogroups.com [mailto:MouthpieceWork@yahoogroups.com] On Behalf Of anchornm@...
Sent: Sunday, 15 December 2013 12:21 PM
To: MouthpieceWork@yahoogroups.com
Subject: [MouthpieceWork] Finishing ebonite
 
  
I bought some ebonite rod, that I have turned on the lathe (for an art project).
It took the shape well, but I can not get it to polish.
The surface is hairy, yellowish, and pitted.
I lowered the feed rate, so the tool could cut and burnish, but that wasn't much better.

What is the standard method to turn then polish ebonite?

FWIW, I contacted the supplier (a pipe stem supplier), and he said that I can not mass finish hard rubber.  My desire would to be to finish the parts (like chess pieces) in some sort of automatic process.  I have a buffer, and ZAM was OK, but crappy, and Tripoli wasn't much better.

Any help would be appreciated.

________________________________
 
   This email is free from viruses and malware because avast! Antivirus protection is active.  

With my mini-lathe I just made from Delrin a replacement knob for a beautifully restored c.1918 telegraph key.  For those interested, a J. H. Bunnell Triumph "Legless" 2A key.  With just the cutting tool I was able to achieve a shiny finish.  In fact, it looked too "new" for the rest of the key, so I sanded it with 2000 grit silicon carbide paper to take off the lustre and hand polished lightly with some plastic polish and a soft cloth.  Now it looks just right.
 

 The tool was one of those small replaceable triangular shaped bits with slightly rounded tips, rather than a sharp point.  I don't remember the radius.

 

 Paul C.

Thanks Tony.
I have created two problems for myself.  There is a raised ridge on all of the parts, so I can not effectively sand -  I tried 400 lightly, then scotchbrite, but not to my satisfaction.  Also, I  need to glue two parts together (black against white), so Delrin is out -- very difficult to glue effectively.




________________________________
 From: Tony Fairbridge <tfairbri@...>
To: MouthpieceWork@yahoogroups.com 
Sent: Saturday, December 14, 2013 11:24 PM
Subject: RE: [MouthpieceWork] Finishing ebonite
 


  
Always a problem, for which I cannot offer a solution. You might try increasingly fine grades of wet and dry. Delrin looks similar and machines well.
Tony F.
 
From:MouthpieceWork@yahoogroups.com [mailto:MouthpieceWork@yahoogroups.com] On Behalf Of anchornm@...
Sent: Sunday, 15 December 2013 12:21 PM
To: MouthpieceWork@yahoogroups.com
Subject: [MouthpieceWork] Finishing ebonite
 
  
I bought some ebonite rod, that I have turned on the lathe (for an art project).
It took the shape well, but I can not get it to polish.
The surface is hairy, yellowish, and pitted.
I lowered the feed rate, so the tool could cut and burnish, but that wasn't much better.

What is the standard method to turn then polish ebonite?

FWIW, I contacted the supplier (a pipe stem supplier), and he said that I can not mass finish hard rubber.  My desire would to be to finish the parts (like chess pieces) in some sort of automatic process.  I have a buffer, and ZAM was OK, but crappy, and Tripoli wasn't much better.

Any help would be appreciated.

________________________________
 
   This email is free from viruses and malware because avast! Antivirus protection is active.  

Well...
Since I can't use sandpaper, I did some research.  2000 grit sandpaper is 10.3 microns.
So I made my last pass before my finish size (of zero microns) at 10 microns, at 5 mm per minute feed rate.
My final pass was at 5mm as well.

It is highly probable that the tearing happens while at about 50 microns from the finished size, so I made successive passes (each time halving my depth of cut and feedrate).
So, from 50 microns and beyond, I kept it wet with a tiny square of green scotchbrite, soaked in rapid-tap and wd-40.


Spindle speed unknown, but as slow as my lathe will turn (probably about 600 rpm)

Roughing passes (to within 300 microns) 500 mm per minute (this yielded long strings, and it resembled threading)

Finishing pass @ 100 microns, 100 mm per min
Finishing pass @ 50 microns, 50 mm per min
Finishing pass @ 25 microns, 25 mm per min
Finishing pass @ 10 microns, 5 mm per min
Finishing pass @ 0 microns, 5 mm per min

Soaked in dishwashing liquid, scrubbed with a toothbrush.
I cleaned the corners and ends with a file, while the next part ran.
Into the tumbler for 2 hours.



________________________________
 From: Will Schmit <anchornm@...>
To: "MouthpieceWork@yahoogroups.com" <MouthpieceWork@yahoogroups.com> 
Sent: Sunday, December 15, 2013 7:17 AM
Subject: Re: [MouthpieceWork] Finishing ebonite
 


  
Thanks Tony.
I have created two problems for myself.  There is a raised ridge on all of the parts, so I can not effectively sand -  I tried 400 lightly, then scotchbrite, but not to my satisfaction.  Also, I  need to glue two parts together (black against white), so Delrin is out -- very difficult to glue effectively.




________________________________
 From: Tony Fairbridge <tfairbri@...>
To: MouthpieceWork@yahoogroups.com 
Sent: Saturday, December 14, 2013 11:24 PM
Subject: RE: [MouthpieceWork] Finishing ebonite
 


  
Always a problem, for which I cannot offer a solution. You might try increasingly fine grades of wet and dry. Delrin looks similar and machines well.
Tony F.
 
From:MouthpieceWork@yahoogroups.com [mailto:MouthpieceWork@yahoogroups.com] On Behalf Of anchornm@...
Sent: Sunday, 15 December 2013 12:21 PM
To: MouthpieceWork@yahoogroups.com
Subject: [MouthpieceWork] Finishing ebonite
 
  
I bought some ebonite rod, that I have turned on the lathe (for an art project).
It took the shape well, but I can not get it to polish.
The surface is hairy, yellowish, and pitted.
I lowered the feed rate, so the tool could cut and burnish, but that wasn't much better.

What is the standard method to turn then polish ebonite?

FWIW, I contacted the supplier (a pipe stem supplier), and he said that I can not mass finish hard rubber.  My desire would to be to finish the parts (like chess pieces) in some sort of automatic process.  I have a buffer, and ZAM was OK, but crappy, and Tripoli wasn't much better.

Any help would be appreciated.

________________________________
 
   This email is free from viruses and malware because avast! Antivirus protection is active.  

Sand to 1000grit, then polish. I use 3 grades of Menzerna bar on different mops.  Supplier's instructions are here http://sem-ebonite.com/cms/upload/Produkte/eboFORM/Bearbeitungstipps/finishing_instructions.pdf. 

Thank you.
My experiments are improving, but far from acceptable.
Your link is a valuable asset.




________________________________
 From: "frymorgan@..." <frymorgan@...>
To: MouthpieceWork@yahoogroups.com 
Sent: Monday, December 16, 2013 7:31 AM
Subject: [MouthpieceWork] RE: Finishing ebonite
 


  
Sand to 1000grit, then polish. I use 3 grades of Menzerna bar on different mops.  Supplier's instructions are here.