Lapidaryforum.net

Please login or register.

Login with username, password and session length
Advanced search  

News:

Welcome new members & old from the Lapidary/Gemstone Community Forum. Please join up. You will be approved after spam check & you must manually activate your acct with the link in your email

Congratulations to denverkris and her Stinking Water Plume Agate Cab!

 www.lapidaryforum.net

Another cabochon contest coming soon!

Pages: [1]   Go Down

Author Topic: Two-headed sphere machine.  (Read 204 times)

0 Members and 1 Guest are viewing this topic.

Ryaly2dogs

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 255
Two-headed sphere machine.
« on: November 20, 2018, 10:18:00 AM »

Open question to the experts on this panel.  I am considering purchasing an old 2-headed sphere machine.  The primary reason, apart from lapidary nostalgia, is that I understand from previous correspondence that a two-headed design is superior at preventing out of round issues.  I continue to encounter this issue, particularly with softer stone (I do not spend enough time watching/adjusting the machine).  The question is, would the two-headed unit be a good go to to "re-round" out of round spheres to your knowledge?  In other words, is it a good tool to have around (other than grinding wheels) to correct mistakes?

Thanks in advance.

David (Ryaly2dogs)
Logged


Jhon P

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1422
Re: Two-headed sphere machine.
« Reply #1 on: November 21, 2018, 06:01:59 PM »

One of my machines is a Covington two. If you don’t watch it it will still get out of round. You have to keep the sphere orbiting. The two head you can use bigger cups and that helps keep the sphere round. If I can’t tell if the rock is orbiting because of no contrasting pattered or color I will mark it with a sharpie. If it’s a good deal buy it. Good to have more than one machine
Logged

Sandsave

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 704
Re: Two-headed sphere machine.
« Reply #2 on: November 25, 2018, 05:12:28 PM »

I'm glad jhon replied, I had a two head in my shop for two months and didn't use it enough to figure it out.
I don't leave anything spinning unattended unless I'm on the finish stages, and then only for a few minutes...
As far as the oblong material, I've had soft and hard try to go out of round, most times it's a self inflicted problem as I might have not spent the time in the preform stage.
I fight it with soft material more so than agate and jasper
When it does happen I pull it off the machine and spend more time back at the preform stage, usually just taking a bit of the bulge out will work, I do have a another set of rough cups I made that are about 1/2" bigger in diameter than all three sets of my regular cups, these help.
Logged

Jhon P

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1422
Re: Two-headed sphere machine.
« Reply #3 on: November 26, 2018, 10:03:41 AM »

Yes once in a while I will have to take one out of the machine and do more hand grinding. It can be pretty important to get a good round preform. The rounder you get it the less time in the machine
Logged

Ryaly2dogs

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 255
Re: Two-headed sphere machine.
« Reply #4 on: December 03, 2018, 06:53:46 PM »

Been absentee for a bit, so wanted to circle back.  First off; thanks for your thoughts, I value your opinions.

I let the 2 header go, but did acquire a second 3 headed machine made by John Van Achen from a design inspired by Wes Lingerfelt.  Same old GE 108 RPM motors that seem to run forever.  Nice to have a second unit!  I am finding switching cup size on the same sphere does help in getting to a nice round.  It all handles larger spheres so will start shopping for larger rough.

I am taking your advice to spend more time upfront on the preform, and also to turn the machine off when I am out for more than a few minutes.

cheers.
Logged
Pages: [1]   Go Up
 

Page created in 0.074 seconds with 32 queries.