gear source

[don62]

have been digesting great info on indexer/lathe combo for under 1k thread and thought i would start a new thread with a specific question:

good source for gears.

have prt standard with 4g upgrade. plan to use vexta stepper and an old shopsmith. the stepper has a 0.50 shaft and the shopsmith has a 0.8125 shaft. open to direct gear or drive belt. need a good source for the gears. thanks don

btw planning to call the mod a shopbotsmith....

create info on the forum - thanks to all

[bleeth]

Misumi USA is one very good source

[steve_g]

A source I used in another life…

http://www.bostongear.com/

SG

[don62]

Appreciate the sources and the information. This has been an ‘interesting’ journey so I thought I would share with you the highlights and some thoughts that hopefully will help others. In the end I ended up using the same items that Brad did way back in 2010. I want to thank Brad for responding to my email with critical information in that he re-bored the drive pulleys to fit his shafts. I was searching for drive pulleys that would fit my shafts, that was the wrong approach – the key is to look for drive pulleys that can be re-bored to the size you need. And that requires finding the information via one of the manufacturers tables. For example if you look at the PowerDrive XL timing belt pulley – 1/5” pitch table you will find item 20xl037-6fs3, under stock bores it shows a minimum of ¼ and a maximum of 9/16. Confirming with the manufacturer, this means that you can take a ¼ and re-bore it to ½ to fit the stepper motor shaft as Brad did. If you look at the same chart, there are several part numbers listed. As long as you select drive pulleys from that same chart, the ‘teeth’ on both pulleys will match the same drive belt. Is used 20xl037-6fs3 and 72xl037-6s5 and re-bored them to the sized I needed, same as Brad did.

My Recommendation: the only way to select the drive pulleys or gears you need is to use the manufactures tables. For Power Drive go to www.powerdrive.com and put cursor on E-Catalogs. Then select the type you want (I chose Timing Belt Drives). You can then either look at the entire catalog or select the section you want ( I selected XL-1/5 Pitch). You are now looking for two pulleys that give a ratio you want and allow you to re-bore to the size you need. And you need to see if you can get the part – I used MSC Direct – you take the part number and put it into MSCDirect search to see if they carry the part and how much it is.

For Boston Gear go to www.bostongear.com. Click on ‘Literature’, then select Gears, Bearings, Couplings & Shaft Accessories from the list with the yellow arrows. Then select rotary drive products (upper left) and either download pdf or by section. I selected Spur Gears. They are far more complex charts, so I went the easier route via Power Drive.

I tried to get MSCDirect and Boston Gear to tell me what they would recommend. Boston was of little help as they wanted measurements that I just could not provide: rotation speed, gear force or whatever. MSCDirect was very polite, but really only have part number knowledge. I went from customer support, to tech support to them calling the manufacturer. They could not answer any other question other than if they have the part in stock.

There is one more area, which I will leave to Senior Members like Brady Watson: pros and cons of belt drive and direct drive. I was concerned about ‘slack’ in belt drive causing backlash, but decided that was not really a problem as the belt drive allowed easier installation and assembly.

Again, my sincere thanks to Brad for his thread on building an indexer and the help from other forum members. I am truly excited about entering the rotary indexer field. All I need to do now is put all these parts together and make it work.

Cheers
don

[blackhawk]

Don - The toothed belts have very little backlash. Direct drive would be fine if you are using a gearbox. The gearbox or stepped pulleys will improve your resolution. I didn't consider direct drive because with the pulley and belt system, you still retain the ability to use the wood lathe as a stand-alone wood lathe.