9" Utilathe Idler Bracket

[YotaBota]

I'm getting ready to put my SM9 on the market but one thing that has always bugged me was the mickey mouse fix for the broken Idler bracket. Since this machine came from a training environment, I would have expected the instructor to show the students a proper repair.

All they did was drill and tap a hole for a set screw at the break point. I added the strap so at least the bracket could be tightened on the shaft.
The bracket is just shy of an inch thick, I don't have any material that thick so I used two pieces of .500 flat bar and welded them together to make a piece 1 inch thick.
First was to rough cut the hole to 1.5ish and the bored it to fit the 1.75 shaft.

I cut the bracket to the shape I wanted and then used my expensive hi-tech slot cutter to cut the clamping slot.

When I drilled the hole for the dowel that the gear rides on, my ciphering was a bit off and the gears would mesh but so tight they couldn't turn,,,,,,, now what?

I didn't want to start over so I bored the dowel hole to press fit a piece of .750 rod, drilled the dowel hole about .030 off center and that let me turn the rod like a cam to get the gear clearance correct.

A quick paint job and then pressed the dowel back into place. Reinstalled the gear and mounted the bracket now we're down.

Thanks for watching, stay safe

 

[YYCHM]

I don't think that taped hole was a fix but rather a factory screw installed to keep the bracket from kicking out of alignment. My lathe has the same thing how ever the hole in the bracket I got from our Ont sourced parts machine didn't match up with the hole in my head stock casting. @Hruul should be able to comment.

As for the broken bracket replacement well done!

Why didn't you just weld (MS) or braze (CI) the broken bracket?

 

[RobinHood]

Nice bracket!

My 9” Utilathe had that anti-rotation set screw it the bracket as well. I guess it weakens the casting enough that it becomes the failure point in a heavy crash - especially if someone replaced the sear pin in the drive train with a steel one...

 

[John Conroy]

Very nicely done. Adding the eccentric so backlash can be adjusted is a bonus, not a mistake!!

 

[YotaBota]

Thanks folks, I was going to do the rounding but kinda like the coffin shape.

but rather a factory screw installed to keep the bracket from kicking out of alignment

Never thought of it being a factory process but it does look that way, they could have put the screw in a thicker part of the casting.

Why didn't you just weld (MS) or braze (CI) the broken bracket?

I figured if it broke once there is the chance to break again.

Adding the eccentric

Eccentric - that's the word I was looking for lol.

The paint is left over from the Logan build and it matches pretty well.

 

[Brent H]

@YotaBota : does this match up with dimensions?

 

[YotaBota]

Not close enough, your bracket must be for the 10".
Here's is what I came up with;

 

[Brent H]

@YotaBota : I will change things up on the drawing. That was made for @YYCHM and just scaled off the photo beside the drawing. I can change a few factors on the Autocad drawing - like making the diameters of the circles properly scaled and see what that does. When we got the donor lathe I had already stripped and shipped those pieces off to Craig and the drawing fell by the wayside. I will update it for any future problems a 9'er might have. The bracket does not exist on the 10.

 

[Brent H]

@YYCHM : yes Craig- but I was only able to scale it from the picture so we were in conversation about the "true" dimensions, the donor lathe came in, it had the arm and gears so it was sent off to you and we forgot about trying to make on. Since @YotaBota made one, I can then rescale the drawing to the true size and .....maybe it will help someone out....

 

[YotaBota]

Thanks Brent - I didn't know where the numbers came from.
The only critical number is the distance between the centers of the shaft (big hole) and dowel (small hole), that sets the clearance of the gears.
Lesson learned - always double check the measurements.

 

[Brent H]

@Janger : Hey John can you edit my post and delete that PDF so it can't be replicated or copied out in the world? I will post the updated one with the corrected measurements from Mike's.