4" snack block

[Frank S]

I made this 4 inch snatch block to use on my Gin pole hoist
The side plates are 1/4"thick the sheave was made out of 3 pieces the 2 outer pieces are 3/8" the inner is 1/4" then welded ground and lightly machined

[metric_taper]

Did you capture the ball bearing with a press fit, and use shims to keep the pulley centered between the plates?

[Frank S]

Did you capture the ball bearing with a press fit, and use shims to keep the pulley centered between the plates?

I went the bushing type bearing route on these, a sleeve fits tight on the bolt, and a bushing pressed in the sheave thin shims on each side

[metric_taper]

Do you use a thrust washer to keep the pulley centered between the plates. I know there is near no axial force on the pulley, but are you keeping it centered via the bushing being press fit, and using a shoulder bolt to prevent the plates from squeezing the bushing? I'm asking what your stack up is to keep this from failing. You have worked on lots of stuff, and kept those good packaging ideas.

[Frank S]

Do you use a thrust washer to keep the pulley centered between the plates. I know there is near no axial force on the pulley, but are you keeping it centered via the bushing being press fit, and using a shoulder bolt to prevent the plates from squeezing the bushing? I'm asking what your stack up is to keep this from failing. You have worked on lots of stuff, and kept those good packaging ideas.

Sorry I didn't fully explain everything currently I am having to carry a separate phone to take my pictures with as my computer can no longer recognize my old phone to up load the photos from it to the PC I haven't activated my new phone yet so sometimes don't carry it to take photos through out a complete build as I normally do. Heck I have already crazed the screen on the new one and it has a triple layer of gorilla glass for the screen supposed to be mil grade tough HA!
Any way where is the skinny the plates are cut from 1/4" plate the sheaves or pulleys as you called them are comprised of 3 pieces welded togwether in the grover then ground and lightly turned to achieve the radius to closely match the cable. the bolts are 3/4" gr 5 the sleeve on the bolts is a cylinder with a 3/4" ID and a 1" OD about .030" longer than the sheave is thick the shims on either side are .010" thick 1" bore and 2" OD the pressed in bushing is Delrin 1" ID 1 1/5" OD .005" longer than the thickness of the sheaves I would have used oilite bronze but didn't have any and for what I am going to use them for it doesn't matter all that much anyway.
so as you see the plates are held tight in place on the sleeve around the bolt and this establishes clearances not that clearances are all that critical either as long as the sheave is free to rotate and the cable cannot become wedged between plate and sheave in the event of fouling.

[DIYer]

Thanks Frank S! We've added your Snatch Block to our Hoists category,
as well as to your builder page: Frank S's Homemade Tools. Your receipt:

Snatch Block by Frank S

tags: pulley

[mwmkravchenko]

Nothing is ever learned without asking questions and getting answers!

[Inner]

Snatch-Block!

[Frank S]

Snatch-Block!

Yep saw that type"O" after the thread was posted too late to correct it LOL

[metric_taper]

After your reply I looked up the difference of sheaves and pulleys, looks like the pulley is the assembly, and the sheave is the free spinning disk with a groove for a rope, chain, or belt.
Thanks for the build up description.