Linear 25HD Heavy duty 1/4" rod by fastmike75

Last crawled date: 3 years ago

Here is another Linear. Had a place where the cases needed to be stronger so it would push and pull. This linear is capable of much heavier pulls than the 31 (5/16") listed in my things. It uses two 3/8" x 7/8" sealed roller bearings instead of the 12mx18mx4m bearings. With a RS555 or 550 motor this linear will pull 10-20 lbs. If you use a metal backing plate to hold it, will probably do more.
Here is a video of the linears working https://www.youtube.com/watch?v=6xfDU2BKSvI&feature=youtu.be
Will work with any motor 540-555 with 25mm mounting centers. The motors I am using are Mabuchi RS555PH-23300, 5050 RPM and 380G of tourque, 12-30VDC, 1.25Amp ( available ebay/Parts Express $3.95). You will need a 93 tooth 48P Associated/Arrma type spur gear with the center drilled for the rod and a pinion gear for the motor. Pinion needs to be 12-15 tooth 48P. There is a 93 tooth spur gears you can download and try in the Linear 31 but it won't take much, try adding shells. Also need two 3/8"x7/8"x9/32" sealed bearings, #R6-2RS. Uses 6-32x1" and 3/4" machine screws. Flat heads for inside. Drill the holes to fit.
You can use either 1/4-20 or 1/4-28 all threaded rod and nuts, depending on how much speed you need. The nuts are inserted into the gear halves and sandwiches the gear with #4 screws. Using 1/4-28 will pull harder but slower. Threaded rod has to be anchored on the other end of the linear or hold the rod with nuts at gear and use as a jackshaft.
Just added all kind of different brackets and nose cones so you can have a variety of mounting options. Mount uses 1/4" bolt. You can also use the linear right through a bulkhead if it is a straight pull. There are screw holes to use 4x3/8 sheet metal screws as bearing retainers if you don't need a bracket or nose cone.
Used this linear for the rippers lift motor on my handmade from scratch metal/3D printed 1/6th scale RC Cat D4G Dozer. Linear works great for this application and will push up the back of the dozer that weights 76 lbs. There is a photo gallery of the RC Dozer build on my website http://www.fastmiketanks.com/
Hope you will find many uses, enjoy!