Jocks, I need your help with determining the Drum diameter for a sander I plan to build. (see earlier post for image).
The issue is that I have two options (sizes of steel tubing I have) for the diameter of the drum, either 4-1/2” or 6-5/8”.
The design of my Drum/Disc sander has both the drum and the disc mounted on the same shaft. This allows me to drive both with a single 2HP, 1725rpm motor I have.
The primary decision I am faced with is which size drum to build. The size of the drum affects the linear speed of the sanding surface. Searching the web, I believe that the majority of sanders have linear speeds of between 2000 and 2300 ft/min. Disc sanders almost all turn at 1725rpm, regardless of size. (I plan that my disc will be 16” diameter).
The following are the speeds of two basic choices I have been studying:
Motor rpm Pulley ratio Shaft/Disc rpm Drum size Drum surface/linear sanding speed-feet/min
or 1725 5:4 2156 4-1/2” 2032
1725 4:5 1380 6-5/8” 2400
The ratios above were selected to get the drum speed near what I think to be correct, with the disc speed varying quite a bit. I’m thinking that the 1380rpm may be fine for the disc, especially considering I’ll have a 16” diameter. Also, I assume the larger drum diameter would assist with heat dissipation. As I have never operated a drum sander before, my questions to you are really focused on the effects of the speed and diameter on the drum.
Thanks for reading. Hopefully my question is clear. Thanks in advance for any input you can provide.
-- Kevin May "Making wood useful and fun!" www.kevinmaywoodworks.com