Keeping shaft bearing supports true...

[/pine]

This week I am going to be fabricating a short (8") jack shaft mounted on a piece of 1/4"x 3" plate...

The two brackets that hold the (flange) bearings will be welded to the plate...I'm sure I can get everything tack welded together but I'm concerned that when I fully weld the brackets there could be some distortion...first on one end then possibly the other...

Any advice or tips to keep the alignment true when I do the welding?...Should I weld short sections alternating between ends?

The brackets are 3/16"...I'm thinking using the 1/4" plate will help some?

I hate to leave the bearings/shaft in while I'm doing the final welding...on one bracket a weld will only be 1/2" from the bearing race...!

 

[hosspuller]

I would not weld the flanges. Bolt the bearing flanges to welded brackets. This will allow the bearings and flanges to find their true axis. Or line bore the flanges after welding.

 

[Stimw]

Standard flange mount bearings swivel in the mounting flange and will find their alignment.
As long as you have things lined up you should be able to tack it together then weld with the bearings removed.
Skip welding does help with distortion.

 

[RickB]

The use of spherical bearings eliminate your concern. Cheap, common as dirt.

 

[/pine]

Thanks...I was hoping to keep it as simple as possible and keep the fabrication to a minimum...

Once I get to the actual (arbitrary) design work and see exactly how much room there is...I will re-evaluate and if there is room I will weld some vertical pieces with slot holes to bolt the bearing brackets to...

The use of spherical bearings eliminate your concern. Cheap, common as dirt.

Do they come with a flange? the bearings I have...have a flange that keeps them from passing through the hole in the bracket...??

 

[RickB]

You could also use pillow block bearings that would bolt directly to the plate. No welding. They also are spherical and self-aligning.

 

[/pine]

You could also use pillow block bearings that would bolt directly to the plate. No welding. They also are spherical and self-aligning.

That is the way I was originally going to go...but one of the pillow blocks would take up too much room and complicate making the shroud...

 

[mikehaugen]

I think there is some confusion as to the type of bearings you are using. Typically, flange bearings are a spherical bearing that swivels in a 2 bolt or 4 bolt flange. I get the impression you are referring to a regular roller bearing with perhaps something like a snap-ring around the outer race?

 

[/pine]

I think there is some confusion as to the type of bearings you are using. Typically, flange bearings are a spherical bearing that swivels in a 2 bolt or 4 bolt flange. I get the impression you are referring to a regular roller bearing with perhaps something like a snap-ring around the outer race?

Yes...I erred in referring to the bearings I have...they are just typical roller bearings where the outer race has a flange...the bearings slip into a bored hole in the 3/16 brackets...the flange holds it in place...

 

[downsizingnow48]

Is the shaft turning fast? If so I would find a way to use mounted self aligning bearings that bolt on. If the shaft turns slow or not at all (like a crank arm for instance) then you could put a stiff Grade 8 or 9 bolt of the correct diameter in the bearings to keep things lined up (more or less) while you weld.

 

[RickB]

Yes...I erred in referring to the bearings I have...they are just typical roller bearings where the outer race has a flange...the bearings slip into a bored hole in the 3/16 brackets...the flange holds it in place...

Well that's not a bearing style I would use on that project. Not using self aligning cylindrical ball bearings is complicating your project and probably compromising its durability.

 

[/pine]

Well that's not a bearing style I would use on that project. Not using self aligning cylindrical ball bearings is complicating your project and probably compromising its durability.

I agree self centering bearings would make it less tedious fabricating...but the bearings and brackets I am using are pretty standard for the application...
...Below is a picture of a kit that is similar to what I am doing...using the same type of bearings...The flat bottomed washer looking pieces/brackets get welded to a frame or plate and are what the bearings fit into...

 

[bigdeano]

I think your best chance to keep everything square is to c clamp a piece of heavy angle iron to the base plate and upright piece to hold it square while you weld. I would also clamp the base plate to a thicker plate so it doesn't warp toward the welds if you can.

 

[RickB]

I agree self centering bearings would make it less tedious fabricating...but the bearings and brackets I am using are pretty standard for the application...
...Below is a picture of a kit that is similar to what I am doing...using the same type of bearings...The flat bottomed washer looking pieces/brackets get welded to a frame or plate and are what the bearings fit into...

View attachment 414627

About all that bearing style is 'standard' for is low speed, low power, low use applications. I guess I can't help you more because of the obvious philosophical differences we have about how the job should be done. Good Luck.

 

[/pine]

About all that bearing style is 'standard' for is low speed, low power, low use applications. I guess I can't help you more because of the obvious philosophical differences we have about how the job should be done. Good Luck.

I'm always open to suggestion...It's not so much "my way" of what I'm doing...it's just what I've researched and learned that a lot of people doing the same thing and use this type of hardware...it's typical...

This is just a little jack shaft for a mini bike to reduce the gearing...it's not going to be used for industrial/commercial purposes...
There are a lot of ways this project could be done (see link below)...I am just trying to keep it as simple and easy without a ton of hours in the process...
I do appreciate all replies...

https://www.google.com/search?q=min...I4ymNtX6gbgC&ved=0CAkQ_AUoAw&biw=1009&bih=590