FF: Forks Brampton Steering Stops

Cyborg

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Just for the record, I wasn’t suggesting the machining and it would be a very poor alternative to adding weld.... and yes adding the weld to the steering stops would be preferable. Although...not sure why adding it to the rib couldn’t be done without warpage.
 

oexing

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Well , yes , a short length of weld on the rib would be OK possibly. But would not want to bet on no shrinkage in the weld that puts bushes out of alignment in the Brampton part. Welding with no shrinkage is an impossible task anywhere so you have to live with it somehow. Anyway, no big advantage to have the rib welded instead on the stops I´d say, so better do the stops.

Vic
 

Simon Dinsdale

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Be careful when welding the stops as the earlier type 2 headlugs were made from mallable cast iron. The later type 4 headlug & series D is the type which drops inside the slotted headbracket were steel.

The photo in the initial post by ogrilp400 is a type 2.

Simon
 

Cyborg

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I’m guessing either way some silicon bronze stitched on there carefully with a TIG would be ok. No need to melt the base metal (if you’re good at it) which means it would be wise for me to take over to the dude who works in aircraft maintenance rather than practice on expensive parts. Currently I’m only certified for yard art.
 

erik

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If someone doesn`t want to weld an other solution is to use the pin of the steering damper on ufm an alter the screw to an big shim which stops the steering.Erik
 

oexing

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Actions speak louder than words : I did some welding on the head lug stops for the Brampton last night, had to do it anyway some day. A grinder test on the head lug produced not so sparkly sparks so my guess it is a low carbon steel casting, no cast iron . I would have been deeply shocked if I found otherwise for a stressed frame member on a bike. So my thinking is some welding for extending the stops a bit is non-critical, hammer tests allright, no brittleness with low carbon steel. Welding on the stops is not critical having no effect to the rest of the head lug dimensions.

Vic
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Simon Dinsdale

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In Know Thy Beast pg 21 and it says the early type 1 head lug of which yours is Vic is a forging but doesn't mention the material. Type 2, of which the initial post by ogrilp400 shows, is a malleable iron casting and last type which is FT1/4 even though the book calls it the third type is a cast steel item of solid H section.

Having seen a FT1/2 type after an accident it is definately mallable cast iron as the headlug split open and the grain structure etc was visible.

So it all depends what type of headlug you have.
 

Albervin

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I have been reading this with interest as I ride an early Series B Rapide. There is no doubt the clearance on full lock is very close and the fitting of the valve lifter needs care. However, I have ridden many thousands of Km and not experienced a problem. The tank is well clear of any impact. The stops hit below the webs. So were the webs supposed to be the stops or just reinforcing? My lower yoke was the only part damaged beyond repair besides the snapped tubes in the great garage catastrophe last year. All other links were just fine. I will be interested to know what steering lock is available with Vic's adjustment.
 

Cyborg

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I don’t know what the factory’s intent was, but it would definitely make more sense if the rib squarely contacted the stop. The fact that it contacts the stops at an angle means that any slight variation in the location of the FT124 (up or down) would allow a greater change in travel. Given the machining tolerances of the day... that could mean you and I were lucky and Master Phelps not so much. Is there something else coming into play that caused him to have a string of bad luck? At the end of the day, it seems (at least in my photo above) that the FT124 hits the headstock before the rib can get square against the stops. Other than rather random tolerances etc the only other variable (based on info provided in posts 1,3) would be the lower bearing. As in were the bearings replaced? What were the dimensions of the replacement bearings versus the originals. Not just the width of the outer, but the total width including outer, balls, and inner. Perhaps the business part of the race wasn’t ground as deep? Again.. given the rib contacting at an angle, it would not take much to allow more travel.

Does the spares co. have any drawings that would show the dimensions of an assembled bearing?
 
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