Turntable? Not another one...

[derekleffew]

... Edit: Oh look at these casters!Rigid Caster, 3 In - Plate Casters - Casters and Wheels - Material Handling : Grainger Industrial Supply ...

No. No. NO.

 

[Thefoxygranpa]

To add some authority to this thread:

NFPA 79 - Electrical Standards for Industrial Machinery Chapter 9 covers control circuits. 9.2.2 defines three categories of stop functions, and 9.2.5.3 covers when and how they are to be implemented. 9.2.5.4 covers emergency stops specifically. And there's lots more relevant info in that document that you should look at. You can read it for free if you register.

OSHA 1910.211-219 covers machinery and machine guarding. (there's less immediately relevant stuff here, but still good to read)

Thanks for that, I read through them and covers a lot of excellent information. Very good to know and I will be referring back when implementing the stop mechanisms especially. Just wish NFPA's wasn't a PITA to read with its whole java thing opening up in a separate window and all

 

[Thefoxygranpa]

No. No. NO.

What am I missing? Seem a pretty solid caster....

 

[Footer]

What am I missing? Seem a pretty solid caster....

Frame is not constructed right, you don't want a really hard wheel for a revolve or anywhere onstage, and its chinese mass produced hardware.

I would suggest going with something like this... McMaster-Carr

I have 50 of those on stage right now for a revolve. Because I am doing a wheels down design I am using swivel casters. They work very well and are comparable to a Colson in my opinion.

Don't skimp on casters. You will be really sorry later.

 

[Thefoxygranpa]

Do you have a product # for that MMC product? It tried to pull up your order history...

 

[Footer]

27075T73 should do ya..

Its a 4 15/16" mounting height with a 330# capacity. They are whisper quiet and built very well.

 

[Thefoxygranpa]

Thoughts on this one?Rigid Caster, 4 In, 140 Lb, Polyurethane - Plate Casters - Casters and Wheels - Material Handling : Grainger Industrial Supply

The 140# load per caster is plenty and then some for the weight I'm looking at.

300# is overkill for my application. But if the couple casters I'm looking are not applicable to my situation and I can somehow justify ~$300 more for the ones from MCC, I'm all ears.

 

[Gregi]

I built a 24" turntable for a production of Les Mis last spring. I used a similar drive system. You can increase the maximum rotation speed by replacing the drive sprocket with a larger diameter sprocket. We used a 2HP, 3 phase motor with a 20:1 speed reducer and it had plenty of beef to drive the turntable at 1.5 RPM fully loaded. I would also highly recommend using the idler sprockets mentioned in an earlier post where the chain engages the turntable. The guides made of lumber will wear out fast. We had to put at least 100# of tension on the chain to keep it from slipping when the turntable was fully loaded with 20 actors and scenery, about 7000# in all. The drive and idler sprockets are available from McMaster-Carr. Make sure you get the proper ID on the drive sprocket to fit the gear reducer. As I recall the sprockets were about $20 each. BTW we used a 3 layer construction for the turntable 3/4" ply each. I'm glad we built it this way when the entire chorus (45 actors) were marching on the turntable for the finale.

Hope this helps.

 

[scenerymaker]

When looking at all of the SEW-eurodrive motors they didn't seem to have a 90 degree output.

The pair of SEW K37DT90L4 motors I have on my 25 foot dia, table have 90 degree gearboxes on them. I have to turn a 3-building set and 50 actors 180 degrees in 20 seconds, including starting and stopping. It takes 2 motors to do that.

I also used 4" casters with Endura solid elastomer wheels, rated at 1,000 lb each, from ServiceCaster.com. I used whese wheels because of the extremely low rolling friction and low noise. I needed 26 of these wheels because most of the cast stands on one half of the table.