Chain drive for slab roller

[NoArtist]

I have had some success lately building an extruder and some custom dies for my daughter, so now I want to move on to the more ambitious project of a slab roller.

I want to build something better than the do it yourself cable driven single roller type. Those are quite clever in design, but also seem to have many drawbacks. My daughter does mostly hand built work from slabs, so if I build one, I really want something with a wide two roller design similar to the North Star.  I plan on using surplus thick wall aluminum irrigation pipe for the rollers.  Knurling the rollers will take some effort, but I think I am up to it, and the tensionizing adjustment does not seem too difficult. But driving the rollers will be the real challenge.  I do not have the ability to machine custom gears, and purchasing them can really run up the cost. Also, gears are much more fussy about precision alignment and engagement. But bicycle chains and gears are readily available and produced at an economy of scale such that they are very affordable.   They also do not require as much precision, and by selecting the correct gears I think I can get a 4 to 1 reduction ratio similar to the high end machines.. But are they strong enough, and are there any unseen issues?

I have seen some moving table style slab rollers that use cables or chains. Other than the known disadvantages of the moving table design over a dual roller design, how do they hold up?  Do the chains wear quickly or break under heavy use? Has anyone ever tried  driving a dual roller setup with chains, and discovered it is a dead end? Does anyone know how much force is needed to drive a roller on a system like this?  And, am I crazy to consider trying this approach? 

The chain path will need a bit of thought to get the rollers to both move in the correct direction, and to also maintain proper tension as roller spacing changes.  But am I missing something else that will be very important?  Eventually I may just give up on the idea and just help her buy what she really wants. But like I said. I know that I can build the rollers and the tensionizer. It would really just be a matter of designing and fabricating the correct drive mechanism.  What types of issues are seen on these dual roller units?

[Mark C.]

My electric Bailey is chain driven-very reliable .

Cables stretch over time.Just design a chain tensioner and it will be trouble free.

Never spent time looking at how its made-it works

I'll take a look at it today and report back

[neilestrick]

If you have the time to take on a project like that, then go for it, but I would consider money spent on a Bailey or North Star slab roller to be well spent. You can just buy the roller mechanism and mount it to your own table.

[Min]

I have a simple slab roller my husband and I cobbled together years ago. We had scrap steel and most of the other bits lying around, it's rough and crude but it works well so we’ve never upgraded. Heavy table, shelf underneath, arborite top. Because we used scrap and all sorts of odd bits the total cost was probably under $60-  We used parts of a rowing machine, weight lifting set..

For the gears, we used #40 chain sprockets and an idler sprocket to tension (on a pivot arm with a simple coil spring), bought new from a discount auto supply place, not much cost. We did consider bike gears but this was way easier.

Height is adjustable on the upper roller, I honestly don’t change the height very often at all. I have a couple thicknesses of boards that I use to run the clay through with, if I want a thinner slab I use a thicker board. 

A piece of redi-rod mounted to the upper bearing is what adjusts the upper roller height. This allows us to adjust the rollers to parallel. Old steering wheel, more than enough torque to feed the clay through.

Re your plan on using aluminium irrigation pipe, that’s great if you can do it. If you can knurl then I’m assuming you have a metal lathe? As you can see on ours, the cylinders aren’t knurled but I’ve never had an issue with it, probably because of the diameter of the pipes. 

 

[Mark C.]

The Bailey has chain drive on one side only-large 1/2 to 5/8th  inch wide chain.I did not remove chain guard so I could see was only a peek

I would favor steel rollers over soft aluminum which is super soft. 

I know a potter who built an electric one with cables-its always going thru cables.

[Denice]

I probably bought my Bailey slab roller 20 years ago.   I just bought the unit and my husband built the bi-level table for it.  Bailey included the plans.   It has not needed any any maintenance since we installed it.     No maintenance is a big deal for me,  my husband has enough things to fix around the house.   My big Skutt didn't fire right last week so he needs to check out the wiring,  another thing for him to fix.     Denice

[NoArtist]

This is all very helpful.  The slab roller is still just an idea, since I have several more time critical projects to tackle. However, if I do decide to build one, I will probably not be worried about using chain drive.