# Mill use for track support in rolling ball sculpture



## markstephens (Mar 14, 2017)

Hi,

I'm creating a RBS using wood, brass and glass marbles as the media.  I'm pretty good at woodworking, but very new to machining.

My router table makes for a poor mill with the use of jigs and, as you can image, it's not very accurate or easy.  The photo shows what I'm attempting.  On the left is the raw stock, a brass pipe 1 5/8" diameter with 1/4" walls (also shown is a 1/8" rod used as track).  I use a jig with a dremel to cut off a 1/4" circle.  A jig on the router table mills the 1/8" holes in the ring (next photo clockwise).  The ring is cut into 4ths, a small flat made on the each of these track supports and a hole drilled into, but not thru, the flat.  Add some solder and you get to the picture on the bottom right.: a marble rolling of a track in dire need of a clean up!

Here are my assumptions based on reading a bunch of books:
 - A mill with a rotary table (?) drills the 1/8" holes.  
 - An end mill cuts the flat on each track support
 - A drill cuts the hole in the flat 

Are these good assumptions?  

Also, can a mill be used to cut the 1/4" rings from the pipe?  (Don't want to buy a lathe... yet!)

Assuming the dremel has butchered out a ring.  Can the mill surface this piece of uneven thickness?

How to hold (with accuracy) the track supports?  Should I drill the holes (and make the flats) before cutting the ring in 4ths?

So... anyone want to convince me to buy a mill!?

thanks,

mark


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## dlane (Mar 14, 2017)

RBS  ? What dose it do


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## Cobra (Mar 14, 2017)

Balls get elevated and roll down tracks to collect and be re-elevated.


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## gonzo (Mar 14, 2017)

I would not bother to notch the ring, but make a jig to hold the rod in place for soldering.
The solder should be strong enough thus making the notch unnecessary.
Making the notches are time and effort consuming and your rbs will take a LOT of them.


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## tincture500 (Mar 17, 2017)

As you mentioned your best with wood. Why don't you opt to make the ring out of wood. Nice walnut and brass rod would look really sharp


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## tincture500 (Mar 17, 2017)

Couple hole saws would make you ring then cut them in half


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## 12bolts (Mar 17, 2017)

Yes a mill would do most of the work as you describe, apart from the ring cutting. But are you just looking at a mill for this job or do you see plans for more different miling in the future? Are you planning on going into full scale production of the RBS and needing mass production parts? More tools is always better, but a mill, and indexer for just this job is going to be pretty $pendy.
It appears you have a drill press? Although this could also be done with just a power drill and vise. A simple jig would enable you to get good consistent results quite easily.


Obviously this is just a quick sketch and the location of the various holes is just arbitary, but with correct layout you could have your jig clamped to the table, insert ring, (without a dowel pin) and drill the first hole. Move ring around and insert dowel pin, drill next hole. Pull pin, rotate ring, insert pin in next hole, drill new hole. Repeat. Once done drilling, remove jig from table, and by using the index pin you can file a small flat for your radial hole location. If you wanted to get really technical I suppose you could also put a hole in the edge of the jig and use that to drill your radial hole. Actually, if you did do that you could probably eliminate filing the flat.

If you are wanting to get consistent thickness of your rings you could make a 2nd jig with 2 holes.


1 is a through hole, neat fit on your tube. Clamp tube so it just projects proud of the surface and sand it flush. This will now be, (within reason), flat and perpendicular. Cut your ring slightly over length, drop it into the 2nd hole, (depth of which is your ring thickness), previously squared end down, and sand it flush.
Hole sawing your rings out of brass plate is another option but will require considerable clean up to get the finish you seem to be after.
It will be difficult to clamp the "dremel butchered" rings and mill them flat.

Cheers Phil


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## markstephens (Mar 18, 2017)

gonzo said:


> I would not bother to notch the ring, but make a jig to hold the rod in place for soldering.
> The solder should be strong enough thus making the notch unnecessary.
> Making the notches are time and effort consuming and your rbs will take a LOT of them.



Gonzo,  I did try this but there is not enough surface area to create a secure bond... even with filing flats on the track .  Too easy to snap on handling and my design depends on being able to remove the track for cleaning, and polishing.  With the notches, I can still snap the support from the track but it takes way more effort.

thanks for the reply!

mark


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## markstephens (Mar 18, 2017)

tincture500 said:


> As you mentioned your best with wood. Why don't you opt to make the ring out of wood. Nice walnut and brass rod would look really sharp


It would indeed!  I'd need to epoxy the track to the wood and I'm not sure that would look so great.

thanks for the reply!
mark


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## rwm (Mar 18, 2017)

Nice project! Please post more pics as you go.
I assume you used regular solder? Silver solder will give you a stronger joint. The soldering temp is higher and you will need to be careful not to deform your track but it is probably worth it for the durability. You may be able to get away without cutting any notches if you do that. Try a test piece.
12 bolts had some great suggestions above. I think the jigs would need to be made of steel, so you would have to have those machined. How many of these parts do you anticipate making? A small Sherline lathe and mill could handle brass parts at this scale nicely. This could all be done with a mill, and rotary table. To make the rings you could just cut off bands with a handsaw and then finish the ends with a rotary table on the mill.
Robert


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## markstephens (Mar 18, 2017)

Wow Phil. thank you for the reply.  

I'm actually doing something similar but with the router table.  I did try to use the drill press, but bit deflection was most problematical.  Holes were not straight or too wide.  The router table produced the cleanest hole by lifting a 1/8" diameter bit up thru the ring to cut the hole.

My jig moves the brass ring in a circle with indices for each hole.  If you look closely at the ring in the original photos, the holes are not quite equidistant from the edge. I think this is due to small location errors indexing the whole device at the router table during setup.  I can live with this, but other jigs depend on the hole locations and it drives my nuts.

To cut the "Dremel butchery", I use another jig using similar ideas as you described.  

OK, true confessions, I'm looking for an excuse to get into machining. Making a brass clock (should never have looked at those Clickspring videos on YouTube) would be soo very cool.  Plus other kinetic sculpture ideas.  I'd prefer to start with only one device and the mill seems to fit better with my current design.  I know it's over  kill for this, but one must start somewhere :>.

Again,  thanks for the reply, I appreciate the time it takes to think about these things!

mark


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## rwm (Mar 18, 2017)

Sounds like you need a mill!
Robert


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## markstephens (Mar 18, 2017)

rwm said:


> Nice project! Please post more pics as you go.
> I assume you used regular solder? Silver solder will give you a stronger joint. The soldering temp is higher and you will need to be careful not to deform your track but it is probably worth it for the durability. You may be able to get away without cutting any notches if you do that. Try a test piece.
> 12 bolts had some great suggestions above. I think the jigs would need to be made of steel, so you would have to have those machined. How many of these parts do you anticipate making? A small Sherline lathe and mill could handle brass parts at this scale nicely. This could all be done with a mill, and rotary table. To make the rings you could just cut off bands with a handsaw and then finish the ends with a rotary table on the mill.
> Robert




I'm using Stay Brite-8 at 6% silver.  It is not anywhere near as strong as brazing, but since I'm soldering in place on wood,  brazing temperatures would cause my sculpture to go up in smoke!  I need about 40 track supports for the current sculpture.  I have more of these sculptures tentatively designed.  And yes, I'll probably be buying a Sherline mill and (later on) lathe.  Not the money so much (it is though!) but the time I need to learn new techniques.   

I'm hoping a mill with rotary table can cut the notches using an end mill moving along the X or Y axis.  Not exactly how to secure the ring (super glue a la Clickspring video or a 3/4 jaw chuck?). 

thanks,

mark

ps just saw your reply... Ah shucks, do I really need a mill!?


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## FanMan (Mar 18, 2017)

Sounds like a perfect project for a small CNC mill, cut 'em out of plate... a fair amount of scrap but you could set it up and the machine cuts a whole bunch of them out while you do something else.


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## rwm (Mar 18, 2017)

You can get plenty  of advice on mills here. I would advise you to go bigger than you think you need right now. Look at the mills from Precision Matthews if you have space.
Start with your tubing and cut slices. Then, I would use a 3 jaw chuck mounted in the rotary table. Use the rotation and the x axis to cut the notches from the inside with an end mill. Super easy.
40 supports is only 10 rings cut. Heck, send me some tubing and I can part off 20 rings to get you started. 
Robert


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## JimDawson (Mar 18, 2017)

Yup, looks like you need a small CNC mill.    Or at least a small mill and a rotary table.


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## rwm (Apr 10, 2017)

Hey Mark- how did you ever make out with this? Any progress?
Robert


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## markstephens (Apr 11, 2017)

rwm said:


> Hey Mark- how did you ever make out with this? Any progress?
> Robert


I'm making progress... going to purchase a Sherline lathe and mill.  I know that's just a tiny bit smaller than the one you recommended!  As I thought more about the problem I realized just how a small machinist workshop would enhance my already extensive woodworking shop.  The Sherline fits my need for the small mechanisms I anticipate in this and future sculptures.  So your message came in while I was designing an aluminum jig to hold the rings on a rotary table plate.  Since the ring is so small, I'll try to use the superglue as clamp technique to hold them to both cut the notches and to use a slitting saw to cut the ring into fourths.  I plan on demounting the jig and giving it an acetone bath to release the four track supports.  If that doesn't work, I'll add four simple clamps to the jig to hold the pieces for cutting.

mark


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## rwm (Apr 12, 2017)

Sounds like a plan. I too started out with a Sherline. Now I have adapted the Sherline spindle as a tool post grinder for my bigger lathe!
Keep us posted and let us know if we can help.
Robert


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