Machinist question

stlmikie

stlmikie

I wish I had more money.
So I have a question from some of the guys that have built bikes. Not even built bike but are pretty savey with bikes. I'm putting a new front end on an old bike. The new front ends steering stems shorter than the old one. So I pressed out the old stem with the intent of pressing it into the new bottom triple. Well I got it out and the old stem is .020 smaller in dia. So my question is outside of having a new stem made what can I do to make the old one work in the new tree? I was going to have a sleeve made maybe that is same inside dia. as od of the old having it threaded inside and the old stem threaded. Pressing the sleeve in then threading the stem in? Am I over engineering this? Is there something simple?
 
Five Five

Five Five

Well-Known Member
that's a thin sleeve.... I would take it to a Mil-Spec plating shop that does electroless nickel plating....have them mask and plate to build it up....it's only .010" per side and electroless plates very even and you wont have to go back and grind it to size.
 
2004BC

2004BC

FREEDOM!!!
Well you could shim the gap then tig weld the stem at the bottom of the lower tree. Many lower trees are welded after being pressed in. Yes that will mess up your chrome on the bottom welding after chroming. You can wrap and cool other areas to limit heat travel. Then paint black. You won't see the bottom of the tree unless you happen to fall down and look up.

:cheers:
 
stlmikie

stlmikie

I wish I had more money.
I would have done what you mentioned BC but the stem is steel and the tree is aluminum. I'll look into the mil spec plating. Like you say five, that is a thin shim. I wouldn't be apposed to making the hole in the tree bigger to house ta bigger sleeve. We shall see.
 
H

hayseed

Member
can you go the other way and mill the tree hole larger to match a more meaty shim of your choice ? , hey its an option
 
stlmikie

stlmikie

I wish I had more money.
That's what I meant. Mill out a larger hole in the tree to get a meatier sleeve in it. Have the sleeve threaded on the inside then thread the stem.



hayseed said:
can you go the other way and mill the tree hole larger to match a more meaty shim of your choice ? , hey its an option
Click to expand...
 
Five Five

Five Five

Well-Known Member
Wild Steed Worx has the capabilities in there machine shop and I probably have a piece of stainless steel bar stock I can give you just give me the length and diameter you need and have them machine you a new stem. With the stainless you can buff it up to be as brilliant as chrome. The sleeve is a good idea just seems to be alot of work for a sleeve

PM Kaptinamerica or Raywood they love a challenge
 
stlmikie

stlmikie

I wish I had more money.
Alright. One more question. When making something like that. Would you make it the same dia. as the hole? Or a ch bigger? If the ch, how much?
 
Five Five

Five Five

Well-Known Member
stlmikie said:
Alright. One more question. When making something like that. Would you make it the same dia. as the hole? Or a ch bigger? If the ch, how much?
Click to expand...
Machinist rule (example) a 1" pin will not fit in a 1" dia hole so I would machine it the same size as the hole for a press fit or maybe .0005" (tenths) undersize which equates to .00025" (tenths) per/side

I would still send the lower triple tree for an exact interference fit. some of the older machine lathes have .005" tolerance on the machine bearings so it would be difficult for them to hold tolerances that tight unless you send the lower triple tree for an exact fit.
 
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