interference fit sleeve

[steven_191]

I'm putting an r1 front end on the mito. I need to make a sleeve to put on the mito yoke stem then this will fit the r1 bottom yoke.

Measurements for the sleeve are
OD 30.30mm
ID 26.15mm
Length (to be determined) probably around 20-25mm

So its not too thick as you can see. I was thinking making it out of brass as I have some brass and it won't rust. Right?

Or should make use something else?

I want the sleeve to be an interference fit onto the stem. It will have a step out at the bottom to stop the stem pulling through the sleeve and to stop the sleeve pulling through the yoke.
I plan to leave the stem in the freezer and heat up the brass or whatever sleeve and slot them together them put that in the freezer and heat the bottom yoke. Should go nicely.

Any suggestions on metals will be handy. I just don't want to use something that will need protection against the elements. I know brass goes a bit shitty over time but its not rust is it? I don't want it plate because that will mean compensating when making the sleeve etc. I think that standard parts are hardened and get quench during which would explain why they are a darker colour and mostly rust free

[Pete.]

Steel stem, alloy yoke and brass spacer? Don't do that!

https://www.engineersedge.com/galvanic_capatability.htm
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[steven_191]

Damn I was hoping that wouldn't apply here. Suppose I'll have to go with steel then. Probably a high carbon.

I could use gold

[Pete.]

[Vincent]

Isn't the R1 front end a bit big/wide/heavy for the Mito?
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Space Is Deep

[steven_191]

[Pete.]

Don't make a hollow alloy one - make it solid. Stems are mostly in shear that's why they are waisted and the bearing seat is thicker. The tensile loads are not very high.

I've got some reclaimed alloy balustrade rods that are a nice quality alloy, not some gummy crap though I obviously don't know the grade. I think the biggest should be big enough for your stem.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[steven_191]

the only issue i can see then with the ally is that the top nut on the r1 gear is quite thin so there wont be much thread to grip.

if i were to put the thread on the inside i can see it being a complete ball ache the get that cut in, fine thread, very precise.

if i use the one i already have, ive got the fixing to suit it. ill go with this for now and i think it should work out ok. otherwise there will be another thread coming.

[kestrel]

[Pete.]

[steven_191]

The Mito stem will be a bit slack inside the r1 top yoke so the easiest option is to just make a suitable washer/spacer to fill the gap. The mito nut goes on a thread inside the stem and has a large overhang. That should cover most of it.

I may look into fixing it solid to the yoke but that will mean interference press fit or weld.

[steven_191]

If I make this sleeve and heat it up to put it on the stem and let it cool down then machine it, would I be able to heat it up again and quench it in oil for some rust protection? The stem already looks like its been hardened or quench due to its dark colour. It do t think I'll be causing any issues by heating it up again would I?

[Walloper]

I LOL when I hear, read, am told to "put metal in the freezer to shrink fit".

Interference fits are VERY tight fits.
It is more of a crush or compression fit.
After fitting the internal part could possible even need re-tooling to maintain the designed fit of the parts it will carry.
This can be worked out by calculation before hand.

https://www.ameritherm.com/PDFs/shrinkfitcalcs.pdf

Steel will only shrink about 0.002" per Inch super cooled to -200 Deg C.

To Shrink fit you would need a temperature well below that of the fridge or deep-freeze in the house for it to be of any significant value.
If the part fits by this alone then it would easily be a low pressure press fit.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[bwprice100]

.
In my old toolmaker days we used to use liquid Nitrogen to shrink fit steel pillars int press tool sets.
Worked a treat but fun to play with; have you ever seen a rubber hose shatter.
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www.eBolt.co.uk www.ToolRoomChucks.co.uk
My bikes 1956 BMW R26 250cc, !981 BMW R80 (was a TIC ex plod), 1994 R100RT, sold my 1981 Yam XS 250

[Walloper]