Fork cup removal

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VintageTwin
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Fork cup removal

#1

Post by VintageTwin » Fri May 12, 2006 2:37 am

How can you make an inner spreading-fingered (bushing grabber style) slide hammer to remove the Bottom fork cup from the frame neck? The top cup is easy then. You can use a driver.



Cotten
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Re: Fork cup removal

#2

Post by Cotten » Fri May 12, 2006 7:18 am

You can use a drift on either end, but to avoid damaging the inner lip of the cup anyway:

Lathe-cut a thick stepped puck that will match the neck bore and cup bore. Slice off two sides of it so that it will slip through the top cup bore sideways, but can be flipped with a long screwdriver to seat in the bottom cup bore.
Bash upon it with a long drift to remove the cup.
Repeat for top cup.

VintageTwin
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Re: Fork cup removal

#3

Post by VintageTwin » Fri May 12, 2006 4:34 pm

Yes. Good idea. That will work. I have to find something that's made up already, as a thick circle of metal. Like welding a two or three metal washer sandwich, then grinding off the edges like you suggest. Good tool. Bettter than a slide wrench. Can't wait to try it. Will support the frame neck on a saw horse.
A 1/2" thick piece of metal that's 1-3/16" long and 1" wide could be pushed up into the bottom cup and made to fit across the steering cup I.D., on it's 1-3/16" end to end side. That would work like you said. If you had a lathe, you could turn an 1/8" radius off each end to make a step. That step would now be 7/8" across the diameter and 1/4" deep and that step would nose into the I.D of the cup stem for a pilot. I have to try and do it without a lathe. Thanks for the heading.

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Re: Fork cup removal

#4

Post by Zup » Sat May 13, 2006 6:41 am

A nice expanding type of lip driver is an automotive cam bearing installer. A round stepped/lipped bushing thats cut into pie shaped 1/4s, then a taper is machined into the backside that has a matching cone that acts as an expander. The 4 pieces are held collapsed with an oversize rubber band, until you start to twist the threaded shaft/handle it all attaches to.
Collapsed it passes through the opposite cup. When the cone is pulled into the taper, it expands out into the bore of the cup, with a lip that hooks the inside end. Then the handle is driven against the bottom of the cup with a suitable sized hammer.... and drives the cup out.
Cottens puck is easier to make & simpler to use. The cam bearing installer is just a neat working concept that can be used in lots of applications.

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Re: Fork cup removal

#5

Post by Cotten » Sat May 13, 2006 8:02 am

Actually, in real life I do not bash the puck and bushing out. I drilled and tapped the puck for a 1" threaded rod that allows me to pull it out smoothly.
Whoops, I confused myself with my fork leg bushing puller. In real life, I just bash the cups out with an aluminum drift and no puck at al

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Re: Fork cup removal

#6

Post by VintageTwin » Sat May 13, 2006 5:21 pm

OK...thanks. Now I just have to find one. The tool you mentioned, maybe Snap-On or Mac makes them. The puck, I have 6 large washers stacked and ready to braze, then I'll grind the sides off so it will pass through the steering head. Why is no tool made and sold for this procedure? Especially that puck thing? It has Taiwan written all over it.

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Re: Fork cup removal

#7

Post by mbskeam » Sat May 13, 2006 8:03 pm

hello, just use a 1 inch dia. steel rod about 10" long and knock them out . just took out a set 2 days ago. no fuss at all. too install them use a piece of 3/4" threaded rod with flat washers and nuts at each end. then tighten them up. saves what ever finish you have on them.

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