Befuddled about bearings, a couple of questions

WobblyHand

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Dec 18, 2019
Messages
1,520
Spent some time looking into bearings. Downloaded the Timken catalog and read it a bit. Have a couple of questions. I think I need a deep groove ball bearing. Hoping it is good enough. Settled on a 6300-ZZ or 6300-2RS. That's a 10mm shaft, 35mm OD and is 11mm wide. I was thinking of using it for a pulley bearing. Want to make a pair of 4 sheave pulleys. Most of the block and tackle rigs I have seen so far are far too expensive for me to justify or far too spindly for me to trust. For this application, do I need better than ABEC-3 bearings? The ABEC-3 bearings are not terribly priced. Or should I be looking for different bearings?

Is the shaft supposed to be an interference fit? If I get a hardened shaft, how do I go about getting it to fit? It wouldn't be easy to turn down if oversized, and of course if undersized it would be useless.

For pressing the pulley wheel onto the bearing, just sneak up on the ID of the pulley to get a good fit? Have some 2.5" 12L14 that could be turned into pulleys, or some 6061.

For all of the above, I'd need either a hydraulic press or a pretty big arbor press? Currently don't have either in my shop. Not adverse to getting either one.

Thanks in advance for your comments or insights.
 

Bob Korves

H-M Supporter - Diamond Member
H-M Lifetime Diamond Member
Joined
Jul 2, 2014
Messages
7,539
What is the application? Or, does it go fast or slow? What kind of load will it pull, and at what speeds? Is it slow or fast being pulled? There will be more questions without some idea of what you are doing with it. What kinds of environments will it be working in? Potentially more questions about every detail, if we do not know if it is for a clothesline or for a zip line, holding up a passenger... More information please, if possible.
 

WobblyHand

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Dec 18, 2019
Messages
1,520
What is the application? Or, does it go fast or slow? What kind of load will it pull, and at what speeds? Is it slow or fast being pulled? There will be more questions without some idea of what you are doing with it. What kinds of environments will it be working in? Potentially more questions about every detail, if we do not know if it is for a clothesline or for a zip line, holding up a passenger... More information please, if possible.
Kind of slow. Like human pulling slow. Holding a lathe being lowered down my (steeper than current code would ever allow) basement stairs. Four sheaves in a pair to get 7-8x mechanical advantage. Indoors. Not used in a marine environment. Human could be at the bottom of the stairwell, keeping the lathe on the track, so don't want any spindly eBay crap.
 

f350ca

H-M Supporter - Silver Member
H-M Supporter - Silver Member
Joined
Dec 15, 2018
Messages
490
I don't think you need ball bearings for this application. A simple brass bushing on a mild steel shaft would take a long time to wear out.
I made these some time ago to hoist my canoe up to the rafters of the shed. They form a two part line to double the mechanical advantage.
KIMG0193.jpg

Greg
 

WobblyHand

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Dec 18, 2019
Messages
1,520
I don't think you need ball bearings for this application. A simple brass bushing on a mild steel shaft would take a long time to wear out.
I made these some time ago to hoist my canoe up to the rafters of the shed. They form a two part line to double the mechanical advantage.
View attachment 382345

Greg
Those came out very nice.

I want a lot more mechanical advantage. The more the sheaves, the greater the friction, which is why I was considering the bearings. I can get all of the bearings for $20, which isn't that bad. A shaft would cost me less than $15. Everything else is on hand, save for an arbor press.

I will consider using brass bushings. They are relatively easy to make. Won't be as frictionless as a bearing though.
 

Ulma Doctor

Infinitely Curious
H-M Platinum Supporter
Joined
Feb 2, 2013
Messages
2,740
the ball bearings would be great

delrin bushings are impressive for load capacity as well as friction
 

rabler

H-M Supporter - Diamond Member
H-M Lifetime Diamond Member
Joined
Feb 25, 2021
Messages
877
Keep in mind that the different sheeves turn at different rates, so you want some sort of way to manage friction between sheeves, like a brass or plastic washer.
 

extropic

Active User
H-M Lifetime Diamond Member
Joined
Nov 24, 2014
Messages
1,461
6300 2RS bearings will be fine if about 750 pound static load is enough for your application. I would prefer sealed (2RS) over shielded (ZZ). ABEC3 is better than you need.
Oilite bushings would be excellent but probably be more expensive than the eBay bearings I suspect you're referring to.
Support the 10mm axle between each individual sheave with plates that are attached to the hook/clevis.
 
It can take up to an hour for ads to appear on the page. See our code implementation guide for more details. If you already have Auto ad code on your pages there's no need to replace it with this code
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock