Lead screw question

[Dan.Tyler]

Depending on the thread of the lead screw, it may provide adequate reduction by itself.

I have built couplers. You would need a lathe. Turn down the end of the lead screw, and bore out a piece of barstock to fit over it on one end, and to fit over the CIM at the other. Drill/tap each for set screws.

Something to note: adding a shoulder onto the outer side of the coupler and combining with a thrust bearing is highly recommended, rather than allowing the CIM to carry the load internally.

[DELurker]

Originally Posted by Dan.Tyler

Depending on the thread of the lead screw, it may provide adequate reduction by itself.

I have built couplers. You would need a lathe. Turn down the end of the lead screw, and bore out a piece of barstock to fit over it on one end, and to fit over the CIM at the other. Drill/tap each for set screws.

Something to note: adding a shoulder onto the outer side of the coupler and combining with a thrust bearing is highly recommended, rather than allowing the CIM to carry the load internally.

Actually, there's an easier way. Last year (2013), 1370 used a lead screw to control their shooter angle. It was a motor (CIM?) on a bracket (made on a drill press) with two AndyMark couplers screwed together (8mm stock & 3/8) flange-to-flange with the 3/8" diameter lead screw in the end of the hub. We did mill a flat in the hub and drill & tap for a set screw in the 3/8" hub. However, the milling can be done with a file just as easily and the drill/tap can be dome on a drill press or *shudder* by hand.

AndyMark part numbers:
am-0320 (8mm keyed hub)
am-0134a (3/8" keyed hub)

We supported the "free" end of the lead screw with a 3/8" IGUS bearing and put a shaft collar on it so if had no way to slip out.

However, we did find that allowing the deck weight to rest in the middle of the lead screw for long periods of time put a bow into the lead screw which led to a funny little wobble when we turned the motor.

I'll see if I can find some pics or take some new ones by the end of Thursday night's meeting (school's closed today - no work in the shop tonight )

[JamesCH95]

On our robot last year our main climbing mechanism was driven via lead screw. We milled the end of the lead screw into a hex profile that fit inside of a Vex gear and drilled/tapped the end and put a bolt in it to retain it on a flanged hex bearing. Worked pretty well and supported the whole weight of our robot.

[DELurker]

Originally Posted by DELurker

I'll see if I can find some pics or take some new ones by the end of Thursday night's meeting (school's closed today - no work in the shop tonight )

OK, it took a little longer than anticipated (weather and such), but here are some pics...

[DELurker]

Originally Posted by DELurker

OK, it took a little longer than anticipated (weather and such), but here are some pics...

And some more... (darned 5 image limit)

[Oblarg]

Turn down the end of the lead screw, use a bearing to take the load, and use a spider coupler.