Need Advice.....Badly

Ok, so I got my KZ stem out unharmed and it is ready to press into my ZRX lower triple that had the bushing made and pressed into the triple, ready to accept the KZ stem......I pressed it in by hand!!

Dang. So whomever made the bushing doesn't understand what an interference fit means. So looking at the bushing, it appears to have been red loctited in place, which will make getting it back out even more fun. So the question is, what now?

1. It is about a .001" over size compared to the OD of the stem. Thought about welding to the bottom of the shaft, then having it ground down, but over size.

2. Somehow get that stupid bushing out and have a new one made. Probable a PITA.

3. Use red loctite between the stem and the bushing and push them back together?

Any other options? Unfortunately the bushing was made of aluminum, so no welding the bushing to the stem with this one.

Set backs like this suck......sorry for the language.

Cory

Id figure out how to yank it out of there and have one made from steel

Yeah I am afraid it will come to that. The ZRX triple tree bore is 29 mm so the bushing takes it down to 28 mm OD which is pretty thin.

Cory

Heat will soften up red loctite, but be careful around other items that may burn/melt. 300-350F should loose up it's grip. Let's hope the former owner didn't use the type that needs 450F to loosen up.

NakedFun wrote: Yeah I am afraid it will come to that. The ZRX triple tree bore is 29 mm so the bushing takes it down to 28 mm OD which is pretty thin.

Cory

Is there room to open triple tree up for thicker bushing?

Yeah, so looking at this again, I took multiple, precision (I have the equipment...) measurement around the diameter of the bushing, stem, and original KZ triple tree stem hole. Here is what I am getting for averages of each measurement point.

Stem Diameter: M1 - 28.05 mm , M2 - 28.06 mm , M3 - 28.03 mm
Bushing: M1 - 28.08 mm , M2 - 28.07 mm , M3 - 28.07 mm
KZ Triple: M1 - 28.12 mm , M2 - 28.17 mm , M3 - 28.09 mm

The KZ triple had the greatest measurement deviances, but since they welded it in, I would assume their machining tolerance they were holding to was not required critical.

If you look at the three measurement points between the bushing and the stem you get a delta of:

M1 - 0.03mm (0.001") , M2 - 0.01mm (>0.000") , M3 - 0.04mm (0.0015")

That is pretty dang close. I am seriously considering knurling or stiffling the OD of the stem and then using a Loctite bearing compound such as 648 or 680 which is said to aid slip fit retaining to a sheer of 3800-4000 psi.

This in conjunction with the retaining steps in the shaft at would prevent downward movement, and the clamping force of each tree to fork, I feel this would be a pretty safe bet that it would never become a problem.

Cory

MFolks wrote: Heat will soften up red loctite, but be careful around other items that may burn/melt. 300-350F should loose up it's grip. Let's hope the former owner didn't use the type that needs 450F to loosen up.

Could always throw it in the oven for a 15 mins prior to dis assembly. Would be a PITA to handle while that hot.... lol

Cory

After I pushed my stem in on my set up for safety i drilled the tree and stem and put in a pin through them to hold as a safety.
Mark

I would seriously think about knurling the stem, then use the loctite. And use the safety pin idea. Is it possible to weld a nut inside the bottom of the stem (or drill and tap if its solid) then run a bolt in from bottom of tree?

Yeah I am going to get a couple opinions from some machinists I know at work. I may just have a steel bushing made and weld the shaft to it. The knurling and loctite would probable be more than enough, and the thought had crossed my mind about having a bolt come up from the bottom. It just seems like if I am going to go that far, just have a new bushing made and be done with it.

Cory

To be honest I would probly overkill it with the bolt anyhow. I do realize it would be overkill though.

Well I am going to weld the shaft and turn
It down on the lathe tomorrow in order to get the press fit I want.

Cory