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Discussion Starter · #1 ·
Question on the fork stem removal. If you have a telescopic fork, the stem is pretty easy to get to on the lower triple tree. Just flip it upside down. How do you accurately remove and replace a stem in say a springer or leaf spring front end? With the fork itself sticking up past the lower triple tree, hard as hell to bolt down or put in a mill? Had a friend that did it with a drill and messed up the fork, so that seems out? Any helpfull hits from somebody that has done it? It is a early 1924 Indian scout front end that the stem is really messed up (unfixable) and i want to replace it with a 1 inch stem. Frame (1924 also) has been modified to use a 1 inch stem. Any suggestions for stem replacement? Thanks?
 

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Drill it undersize, and then die grinder to take the rest out. Go around and around inside the hole. As the stem leftovers get very thin the metal will start to turn blue. Carefully grind until you hit the brass.
 

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If I'm reading you right, and please correct me if I'm not, you are trying to machine out the old stem from the yolk(lack of a better word)?

Is there anything left of the old stem at all?

Assuming I am right about what you are trying to do, and assuming there is anything left of the old stem, here is what I would do.

Using a bridgeport or any vertical mill, clamp a knee to the table. A knee being any right angle plate with enough surface area to span the width of both legs of the fork and allowing room for toe clamps or forged c-clamps.

Mount the knee so it is flush with back of the table on the mill. Clamp the fork assembly to the knee using V-blocks, screw jacks, and either toe clamps or forged c-clamps. The legs hanging down, and the stem sticking up and generally parallel to the spindle.

Using an indicator and the quill, indicate up one side of the stem and true the fork assembly to this degree of freedom. Now rotate the indicator 90° and indicate up and down the stem again. Adjusting until the stem is parallel to the spindle in this orientation.

At this point, you have the fork assembly mounted and true to the spindle. Now, using your indicator again, qualify the stem and zero out the x and y axis on the machine. Select your tooling and have at it.

Bear in mind that when clamped using v-blocks and jacks, torsional rigidity of the part being machined is not 100%. A deft touch and sharp tooling, you'll have it out in no time.
 

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some of those 20s forks have 3 tubes sleeved over each other and theres a pin running thru the cast ....below the bearing surface flat.
If you have all the paint removed youll see. Looking up the centre you should be able to see it . That thing should press out. ***unless** theres some welding they did before attaching the tops of the legs.
My ones are bead blasted so I cant tell if its welded.

chuck up a pic , if yours are sleeved you might be able to use the existing one as alignment for an extension replacing the damaged section.

I should get my lazy arse to take a pic of what my forks look like. I think its 3/4" inside 1" inside 1 1/4"
 

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Discussion Starter · #6 ·
thanks for the info and suggestions, it is appreciated and gives me some new perspectives. thanks again!
 

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Im guessing the frame had the neck screwed over with cups for tapered bearings.
Id get a new tube threaded same as original and use the existing 1 1/4 inch tube thats already in there as the seat and then have an internal tube to stiffen it all up. just like VL HD frame tech.

***I wouldnt press any thing in = the cast would shit itself.

the bike weight rests on the casting which rests on the fork legs.
the stem keeps it all aligned , those days theyre pretty light bikes thats why theyre not solid.
Use the top handle bar tree for alignment and braze from the bottom.
Im guessing your forks have the pin to stake it all down.

Only suggestions or ideas here
Damn shame about the frame . Im on the hunt for 1 at the moment .
see the pin just below the bearing surface? right pic
 

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Digging up an old post here with the hope that there was progress since Flatman's original questions back on 012.

Hey there Flatman (If you're still around). I've got an early 20's Indian Leaf fork with a feked stem and was doing a search regarding stem replacement and came across your old post on the JJ.

Did you ever get around to trying a stem replacement?

If not has anyone else tried this since the original discussions in 2012?

Thanks,

Adam
 
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