Question About Linear Bearing (LMH16UU) 4

[Badger The Bodger]

Quick question; does anyone know whether a linear bearing, such as the flanged unit with part number LMH16UU, will allow for a twisting motion of the shaft (roll), as well as longitudinal movement?

 

[3DDave]

I expect that linear ball bearing guides will not be particularly tolerant of shaft rotation, but will not entirely prevent it. The problem is that the balls will be in sliding contact with the surfaces of the guide slot.

Follow this link:

https://www.thkstore.com/files/index/download/id/329/

I see the following on page 111 of that PDF:

Rotational Use Not Allowed
The Linear Bushing is not suitable for rotational
use for a structural reason. (See Fig.10 .)
Forcibly rotating it may cause an unexpected
accident.

 

[dvd]

Probably a good usage for a Pacific Bearing -

http://www.pbclinear.com/Linear-Plain-Bearings-with-Simplicity-Maintenance-free-Liner

 

[Badger The Bodger]

Thanks for the info guys, very helpful! I guess a pacific bearing is the way to go.

 

[dvd]

Badger -

Just make sure that the pressure and velocity match bearing capacity.

p.s. - are you a bodger, as in green wood work? I do that myself.

 

[Badger The Bodger]

Okay, thanks for the heads up. I think I should be okay as what I need it for is quite a low-pressure, low-velocity application.

I didn't mean bodger in that sense of the word, never heard that one! Done some woodworking in the past, but not that kind.

 

[sreid]

Ball Bearing Cage Bushings.

https://www.precisionballspecialties.com/ball_bearing_bushing_pins.htm

 

[Badger The Bodger]

Thanks for the suggestion, looks like it would do the job but I was hoping to find something with a flange and bolt holes to secure it to a metal plate.

 

[sreid]

No flange but one could be added.

https://www.mcmaster.com/ball-bushings

 

[3DDave]

A flange probably won't work. Since the balls are captive and don't recirculate, they will tend to travel at half the speed differential of the separated parts. Adding a flange and tying them to one part will force the balls to skid. The McMaster Carr units are linear bearings, so they have recirculating paths and cannot rotate as the OP desires.

I do see McM-C offer linear/rotary versions, which look like a linear inner bearing with a rotary bearing on the outside.

 

[sreid]

Wrong McMasters Link.

Linear and Rotary Ball Bearings


Engineered for simultaneous linear and rotary motion, these bearings allow rotary speeds up to 3,600 rpm. They are for use with round end-supported shafts. The fixed-alignment design is for use where shaft misalignment is unlikely. End seals keep lubricant in and dirt out. To install, slide bearings into a housing (not included) and secure with two retaining rings (sold individually).

For technical drawings and 3-D models, click on a part number.For technical drawings and 3-D models, click on a part number.

Bearings


External
Retaining
Rings
For Shaft
Dia. Overall
Lg. For Housing ID Retaining Ring Groove
End-to-End Lg. Dynamic Load
Capacity, lbs. Dynamic Rotary
Load Capacity Max.
Speed, rpm Max.
Temperature, ° F For Shaft Material Each Each
Fixed Alignment
Steel Bearings
3/8" 7/8" 0.6250" - 0.6255" 9/16" 70 29 lbs. @ 500 rpm 3,600 200° Stainless Steel, Steel 6485K11 $75.00 9968K23 $0.40
1/2" 1 1/4" 0.8750" - 0.8755" 7/8" 185 76 lbs. @ 500 rpm 3,600 200° Stainless Steel, Steel 6485K12 78.57 9968K24 .56
3/4" 1 5/8" 1.2500" - 1.2505" 1 1/16" 325 133 lbs. @ 500 rpm 3,600 200° Stainless Steel, Steel 6485K14 85.71 9968K26 .85
1" 2 1/4" 1.5625" - 1.5630" 1 5/8" 450 185 lbs. @ 500 rpm 3,600 200° Stainless Steel, Steel 6485K15 151.79 9968K27 1.21
1 1/2" 3" 2.3750" - 2.3760" 2 1/4" 935 383 lbs. @ 500 rpm 3,600 200° Stainless Steel, Steel 6485K17 266.07 9968K29 2.93