Using a tumbler to remove fine tooling marks

Becuase I’m starting to get annoyed with machining times on 1/32nd ball endmills with a 10% stepover…

I have never used a tumbler (vibrating or rotating) for any sort of polishing, sanding, or finishing operations but I’m wondering if they would be adept at removing fine tooling marks such as the lines created by a parallel tool-path and say a 50% stepover?

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And what material would you be putting in the tumbler?
And what marterial would you be polishing with?

Hardwoods…maple and walnut primarily

I’ve done pretty much 5 mins of googling on the subject but dry sand seems like at good idea at the moment.

I asked because I want to know how much damage the rest of the surfaces will undergo before the line from a parallel path is removed. On the extreme end I’m visualizing a coffee cup upside down; it seems like the sand would do a lot of damage to the lip before it got the inside-bottom of the cup smooth:

I’m curious about what you are making with 1/32in ball endmill using 10% stepover and still get visible machining marks. Is this 3D stuff? A ball endmill is not good for pocketing. Maybe it is your milling startegy that should be looked at.

That’s the think about a vibratory - it gets everything about all the same as long at the abrasive is much smaller than the thing you’re tumbling. You submerge the “thing” fully in the media, it gets a (broad hand wave here) even finish all over. It does mean that things like sharp outside edges will get knocked down as much as any surface ridges do.

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Luc what I’m saying is that with a 10% stepover it’s generally pretty okay, but it can take…forever. So a 50% stepover and a tumbler would be preferable for 4x less machining time.

Ok but what are you having a problem machining, maybe a change in endmill or setting could provide you a better outcome. A 50% stepover is usually not advisable for example. A ball endmill is usually not good for pockets. Tramming of your spindle may also be an issue.

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How tiny are your parts that you need to use a 1/32” ball at 10%? If the parts are large enough you may get a better finish with a larger tool. At CNC Cookbook they have a pretty good article that describes step over versus scalloping. Which a larger ball end you might get a better finish at a faster rate. If possible you might look at that? I don’t know what you’re making so I can’t say for sure. In my day job tumblers are frequently used, but on metals, not wood. I’m not sure what a media tumbler would do to wood, might be interesting? Here’s the article from above:

Let us know what direction you take, it’s an interesting topic.


Say I wanted to add this texture to the surface to a large quantity and a wide variety of items, but all those items would be relatively small and could fit in a 5-gallon bucket sized tumbler.

I had some success with one of those soft sander balls attached to a cordless drill, but it’s not a strategy for a lot of this texture.

I think you might also consider the varying density of wood, you might end up with grooves in less dense areas and ridges along more dense areas. This would obviously depend on wood species.



Es muy interesante la observación . soy un completo analfabeta del sistema CNC en G-code mucho mas he ido aprendiendo poco a poco por la necesidad de conocer este paraíso . Y divago cuando pienso en lo que usted dice imagino la misma máquina dando un barrido y cuya herramienta podría ser una pistola para hacer el sandblasting para darle un acabado en cobre hasta o poder llegar al enchape en oro si es necesario todo de forma digital . Es tremendo pensar lo gigante de este universo .

In my professional, non-Nomad based line of work, we use a media tumbler a ton on production CNC parts and it’s a near magic cheat code to get parts looking nice for low effort. I have only really used it on metallics and it works wonders, nothing beats like 20 minutes in corn cob…seriously.

Unclear to me how well it work work on wood but conceptually it checks out. Keep in mind, a lot of media tumbling is really an art and not a science. Once you dial in a process, it’s really repeatable, even if you can’t explain why a certain time duration, tumbler RPM and medial give magical results.


Your work is fairly intricate and while you will probably smooth your pieces if you use a media tumbler you may also remove a lot of the details too. Sharp points may become flatter just like the erosion has turned mountains like the Rockies into the Appalachians.