Bridgeport J Head gear housing cover cracks?

B

Brandenberger

Hot Rolled

Joined

Sep 19, 2017

• Apr 14, 2018

• #1

Hi,

I’m replacing bearings on a step pulley (J Head) Bridgeport. In cleaning the aluminum back gear housing cover, I noticed it has some cracks on the top surface.

It came off easily so definitely didn’t happen prying it off.

The cracks don’t seem to go through the casting though, and the part doesn’t seem to have any flex.

Is this normal?

I’d prefer not to have to replace the part!

Two photos attached: one showing the machined bottom with no cracks... then the top surface width cracks radiating out from the central spindle shaft hole.

Thanks
Phil

 

Richard King

Diamond

Joined

Jul 12, 2005

Location

Cottage Grove, MN 55016

• Apr 14, 2018

• #2

give these guys a call Monday.
http://www.machinerypartsdepot.com/

 

JRIowa

Diamond

Joined

May 27, 2003

Location

Marshalltown, Iowa, USA

• Apr 14, 2018

• #3

The cracks don't shop up very well for me.

Anyway, do what Rich said. The part number is 12143452 which has been replaced with 12193452. I checked, not available from either BP or H&W. So, it's find one better than yours or use what you got.
JR

 

B

Brandenberger

Hot Rolled

Joined

Sep 19, 2017

• Apr 14, 2018

• #4

Thanks, I got the bearing kit from H&W... i’ll Ask them Monday.

Phil

 

Z

Ziggy2

Stainless

Joined

Jun 22, 2013

Location

Northern Il

• Apr 15, 2018

• #5

I don't think those are actually cracks. More likely casting issues.

Even if you do think you want to replace them, your going to have to find the off another head. You will very likely not find them available as they are not e=wear parts.

Worst case scenario where the cracks do need to be addressed, you would be better off to just bore the housing and insert a new bushing. Then bore to size.

This is a step head after all, so none of the forces are substantial. Likely the things you really do need to worry about are down on the saddle, knee, or possibly the quill-spindle. This is an area that will not have any major effects on machine performance.

 

B

Brandenberger

Hot Rolled

Joined

Sep 19, 2017

• Apr 15, 2018

• #6

That’s what I was wondering, whether this is a typical casting result for aluminum, but just a surface defect. Since it doesn’t telegraph through to the bottom machined surface that’s my hope...

I don’t think that section has any forces acting on it at all really? The counter shaft bearing for the back gear is held by that cover through... but there are no cracks on that area of the part where there is more ribbing and thickness.

Thanks
Phil

 

JRIowa

Diamond

Joined

May 27, 2003

Location

Marshalltown, Iowa, USA

• Apr 15, 2018

• #7

If you're really worried about it, take the part to an automotive machine shop and have them LP (liquid penetrant) it.
JR

 

B

Brandenberger

Hot Rolled

Joined

Sep 19, 2017

• Apr 16, 2018

• #8

JRIowa said:

If you're really worried about it, take the part to an automotive machine shop and have them LP (liquid penetrant) it.
JR

Click to expand...

Reassembled as-is, runs nicely with the H&W
Bearing kit.


Thanks!
Phil

 

rons

Diamond

Joined

Mar 5, 2009

Location

California, USA

• Apr 18, 2018

• #9

Brandenberger said:

the top surface width cracks radiating out from the central spindle shaft hole.
View attachment 225777

Click to expand...

I would make a mixture of fine aluminium dust and JB Weld or Super Glue and fill the cracks with a tooth pick. Really jam the stuff in. The next time you pull the cover you won't remember that that were cracks.