Creating thread on a shaft and assembling a bolt to hold a bearing

[ptr727]

Hi, I am trying to create an shaft to hold inline skate wheels at both ends fastened with lock nuts.

To do so I create the shaft, say 12mm dia, then I add a thinner section on the end, say 8mm dia, to fit a standard 608 skate bearing, then I cut M8 thread at the end of the shaft, and I place a M8 nut, and I want to assemble the nut on the thread.

I get to the assembly phase, but I cannot figure out how to place the nut on the thread.

Questions:

1) When I create thread, say for M8/1.25, do I make the shaft 8mm, or do I make the shaft thinner to match the inside of the thread?

2) When I import an M8 bolt, say from McMasters, do I use STEP format of SolidWorks format, they appear the same, but the STEP file is much smaller?

3) Is there an easy way to snap the imported part to the center of the bolt/rod, or to snap one surface in the part against anotehr surface, without needing to super zoom and move around?

4) How do I account for tolerances in CAM, i.e. if the shaft is 8mm and the 608 bearing ID is 8mm, do I just leave it as a perfect fit, or do I specify some smaller dimension to ensure it can move by hand?

5) How do I assemble the nut on the thread so it models motion, i.e. thread in and out, or if not supported, how do I model it to spin in place? 

Thank you

[HughesTooling · Accepted solution]

To answer some of your questions.

You can add a Joint Origin to the nut and bolt. Start the command select a face then select the center point of the face.

If you model the threads in Fusion, Fusion changes the sizes to the recommended for the nut and the bolt. One problem if you model the threads, I don't think you will be able to use them in the CAM, it would be better to stick to just the visual unmodeled type.

Mark

[HughesTooling]

Here's an example of what Fusion does when you add a thread to an 8mm cylinder, it reduces the diameter to 7.866. Because of this I would extrude another 8mm cylinder after adding the thread.

Mark

[ptr727]

I got the nut to slide on, thank you, the set join origin did the trick.

 

I would still like some advice on my otehr questions?

[HughesTooling]

Here's some info on limits and fits. Normally you'd draw to size and specify a limit on the 2d drawing and it would be up to the manufacturer to hit those limits. Do you have a CNC lathe and is it good enough to hit the limits required. For repeatable fits for bearings I'd probably turn over size and grind.

Not sure why you'd want to go to all the trouble of modeling the movement of the nuts on the shafts but take look at the Building Assemblies section in help.

Mark