Jump to content
I Forge Iron

Recommended Posts

I have been working on converting an old treadmill into a tumbler for a few weeks now.  This weekend I finally got it all up and running.  Thanksfully my torque and rpm calculations seem to be about spot on and the motor has been powerful enough (so far).  

Sorry for the messy video.  This is my first youtube video and I was trying to get it posted as quicly as possible.  If there is interest in the tumbler I can go back and do a better video showing what modifications I did to the treadmill to make this work.  

 

Edited by intrex
Link to post
Share on other sites

Hey Frosty, 

I just pulled 6 of these out of the tumbler from this weekends smithing after etching in vinigar overnight (they were tumbling during the video).  They were tumbled for 4 hours at about 25rpm.   It got all of the scale off and polished most of the exposed surfaces.  It didn't get into the twist and scrolls as much as I was hoping.  In an attempt to get more polished pieces I am going to try adding water and soap on the next run.  

Since I spent nearly nothing on the actual build I broke the bank a little bit on the media.   I wanted something that would polish and not have to be replaced or rust so I ended up buying 10lbs of stainless steel jewlery media. I probably need another 5lb of media but I am going to try to get by with what I have.  

 

20150309_182657.jpg

Edited by intrex
Link to post
Share on other sites

Looks pretty good but I don't think it's completely descaled is it? I'm thinking SS tends to be less abrasive than scale so might not be the best media. How about ceramic media?

Soapy water will rust the pieces almost as soon as they dry. If however you add some water soluble oil to the mix it should give you time to finish the pieces before they rust up. Heck, maybe add vinegar to the mix to help soften scale as it tumbles.

Frosty The Lucky.

Link to post
Share on other sites

Forge scale is probably the hardest thing in your shop.  Most stainless is pretty soft until you abuse it somehow.  Might not act on scale as fast or well as you want.  That said you got the edges polished up, that's what most folks are after with a burnished or hand sanded finish.  Keep experimenting and let us know the results!

Link to post
Share on other sites

I ran another test tonight with adding simple green to the mix.  This really seemed to help.  It still isn't as aggressive as I was hoping but it is close to what I wanted.  The media doesn't seem to do a good job in the twists.  I ran the tumbler for 98 minutes for this second test which was probably less that half of the first run and the results were much better.  

How much media do you usually put into your tumbler?  My media only fills up about an inch depth of the bottom of the barrel right now.  How long do you usually tumble parts for?  

Link to post
Share on other sites

On the run tonight I ramped up the speed a little bit.  It was originally at 18rpm and I bumped it up to 25rpm.  I also added about a cup of simple green to the mix in the hopes that it would help with the scale removal.  I don't know which thing made the different but the results were much better after another 1.5 hours in the tumbler.  All I did was take them out of the tumbler and dry them with a towel before taking these pictures. 

 

 

 

 

20150311_205903.jpg

20150311_205839.jpg

Link to post
Share on other sites

Hey Frosty, 

Thanks for all of the feedback.  I need to get those finished and out the door so I think they are as finished as they are going to get.  

I will probably forge another batch this weekend and try adding something into the mix for abrasion.  

 

Link to post
Share on other sites

I typically run my tumbler for about an hour and it removes all the scale.  The medium I use is forged offcuts,  when I hot cut the ends off work I save the offcuts and throw them into the tumbler as my medium.  With them being hot cut the cut end of the offcut is quite sharp. I am quite surprised at how sharp the ends are even after months in the tumbler.  If you have an ironworker or have a friend with one I have heard good things about using punchings as tumbler medium for removing scale.   I think the stainless medium may not be heavy enough I am assuming they are thin pins.  I think some weight in your medium helps hammer off the scale. 

Edited by JNewman
Link to post
Share on other sites

dose the drum have any type of agitating fins on the inside? maybe interrupting the simple rolling motion will help?

​Yes Jimmy, at least a little something. Most commercial tumblers are 6-8 sided and don't need a lift flange. Round tumblers on the other hand need something to lift and turn or drop the material so it doesn't just slide down the side as the drum turns.

Yo don't want a big lift flange though, the idea isn't to drop it against the far side perpendicularly. You want it all just rolling along gently, the lift lug basically stirs it so it has to tumble instead of slide.

If your tumbler has a lift flange rather than being polygonal you must keep a minimum load in it or the flanges will pick material up and drop it across the drum and damage it. Enough material must be in the drum drag it off the flange so it can't be lifted and dropped.

Or rather than use a piece sticking straight out, a piece of angle iron welded to the inside of the drum so it forms a closed wedge shouldn't be able to lift and drop material.

Thanks for the question Jimmy it brought back tumbler characteristics I haven't thought about in 40 years or more. Dad was a rock hound and had more tumblers than any sane person could want but they were almost always in use so I guess it wasn't so crazy.

Frosty The Lucky.

Link to post
Share on other sites

Hey Jimmy, 

Maybe you can't tell from the video but the tumbler is a 6 sided octagon stainless steel barrel (with an internal rubber lining).  I am going to try a few more things on the next tumbler run before giving up on the current media I have.  I am planning to add some course grit silica carbide to the next run and see how it goes.  

The tumbler journey continues.  

 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...