I was looking for a surplus electric window motor but found this one: 46 RPM, 24 V DC @ 260 mA, 5/16 output shaft. Attach 11 in. 5/16 all-thread and carriage with brass nut. U shaped guide rails support carriage on ball-bearing wheels[4]. CAT # DCM-287, All Electronics. I made one several years ago , just different motor and length,no problams.