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oolieiv
10-05-2012, 11:31 PM
The front fork in that picture, a magnet sticks to it, but I have done all the voodoo I can do... and I cannot get a 3/8" steel steering control tab to weld to it.


5408

Is it possible that I have a non-ferrous fork, with a ferrous coating that is causing the magnet to stick? Bike is a Pacific brand, fork is suspended, magnet sticks RIGHT WHERE I'm trying to weld. I have ground off the coating, I have tried welding directly TO the coating, I have welded the other tab onto a head tube, so I know it is not the tab that is at issue.

Or is it an issue with it being a suspension fork?

Need some help on this one.

-Louis

oolieiv
10-05-2012, 11:45 PM
Mig flux-core welder in case it matters

darnthedog
10-06-2012, 12:07 AM
I am not familiar with the brand But I am wondering if the magnet sticks as strongly to the area being attempted to welded as it does to standard mild steel tubing? It maybe possible that the magnet is being attracted to the spring inside the suspension? Are you getting any weld material to penetrate the fork tube? Is it a hydraulic fork? The oil may be keeping the metal too cold to weld on. So you need to crank up the amps. That is a few thoughts anyway. Hope that helps. Also remember you have to weld on bare metal- not coating or oil. I'm sure you knew that- but it was a reminder just in case.

oolieiv
10-06-2012, 12:13 AM
I'm not actually welding on the suspension part. Just above the fork crown. Welding on bare metal. Tried it on max amps as well. Seriously doubt the fork is hydrolic, as pacific is academy sports store brand, i.e. wal-mart bike. Magnet feels the same on the fork as it does on the square tubing I made the rest of the bike out of, and not attempting to weld where a spring would be. Welding to steer tube on fork, just below fork crown race.

Tradetek
10-06-2012, 01:05 AM
Welding to steer tube on fork, just below fork crown race.

Let's be clear... the fork's steerer tube is the tube that goes through the head tube. A traditional bike only has one steerer tube.

The fork crown clamps/fits into the steerer tube and the fork legs fit into the fork crown. You will have one fork crown and two fork tubes.

With the description above what exactly are you trying to weld to?

oolieiv
10-06-2012, 01:07 AM
The steer tube. In between the bearing race, and the crown.

oolieiv
10-06-2012, 01:22 AM
welding the gray arc (on the yellow part) to where the blue arrow is pointing Red line represents bearing race5410

Ticktock
10-06-2012, 02:41 AM
HI,
It is more than likely that you have steel forks fitted into an alloy "crown" , with a steel steerer tube cast into it.
If this is the case you cannot weld to the alloy, as you have found out.
Best test is to run file accross the crown. You will feel and see the difference . if you can scratch the bare metal of the crown easily, it is alloy. I doubt there would be any oil at the top of the fork to cause a problem.
If it is alloy, then you have little choice but to weld a bracket to the steel fork tube, but I have not had to do this yet.
just work out where you want the hole to be, and shape a bracket that puts the hole where you want it. leaving room for the ball joint and nuts etc.
The alloy will extend from the bottom of the lower bearing race to the bottom face of the crown! So your magnet may be pulling towards the steer tube inside.
Hope that helps,
Steve G

oolieiv
10-06-2012, 02:45 AM
Solution: If steering tab will not go to fork... then fork will BECOME steering tab.


5413


I drilled the fork crown, ran a bolt through it, and now the foork crown, is the steering tab. I get ~30 degrees of turn out of this setup. May not be ideal, but this way I can go forward with the build, until a suitable replacement presents itself. I suppose I could bolt a tab to the bolt, that moves the rod end over another inch or so to the left, but for the rest of mockup, this will likely be my setup.

I'll get some washers to stack in the gap between the end of the threads, and the fork crown, or I'll get a more appropriate length bolt next time I'm at a hardware store

Ticktock
10-06-2012, 02:56 AM
If you really get stuck , an alternative, not on the plans, is to run the steering rod from the underseat ball joint, OVER the cranks,
and fit the front steering arm onto a gooseneck at the top of the head, just like handlebars.
This would work on my LWB, which is nearly the same layout, so it may work on yoursw.
Take a look at mine in the gallery. and you will see the front end like this.
Steve G

oolieiv
10-06-2012, 03:26 AM
That real-estate's already pretty crowded with my size 15 feet (US sizes) on the pedals. Heal strike on frame is very nearly a concern. I'll either make this work, or find a new fork for final build.

socialtalker
10-06-2012, 01:05 PM
i am just wondering out loud if brazing the tab on with a gas torch would have worked.

oolieiv
10-06-2012, 01:23 PM
Might have... But as I don't have a torch...
Went and bought a 10 dollar backup fork at an lbs. rigid though and because of that, shorter which will change the steering head tube to ground angle, so I'm still going to try to make the setup I have work

darnthedog
10-06-2012, 02:13 PM
That real-estate's already pretty crowded with my size 15 feet (US sizes) on the pedals. Heal strike on frame is very nearly a concern. I'll either make this work, or find a new fork for final build.

The front fork should be well beyond the size 15 shoe. So a tab attached to the fork instead of the crown should not affect the real estate of said foot. I only say this in case the right turns are too restrictive. The tab can be shortened to have it out as far as the plans call for in order to avoid the size 15 shoe- I nearly share your foot problem with a Size 12- And I have a couple Uncle's who have a size 16 and larger, they really have trouble getting shoes. Anyway it was just a thought IF you have turning radius problems. Otherwise that was a very creative solution you came up with if it works for you. We are all cheering you on that it works- not criticing your build per say. And only offering alternative suggestions to save you from haveing to invest in another fork. Any whoot - Hope it works for you as is.

oolieiv
10-06-2012, 04:28 PM
The bit you quoted, was in reply to Ticktock's suggesting I run the control bar OVER the cranks instead of under it. What I emant was the area between the cranks and the frame was pretty crowded.

darnthedog
10-06-2012, 06:21 PM
Ah- missed Ticktock's posting sorry guys. I sometimes read through these posting too fast between breaks I get. Was just offering suggestion to help with tab mounting issue.

trikedoc
10-06-2012, 06:54 PM
oolieiv'
I believe what you have is a Chrome plated steel fork. You may not have ground through the chrome then nickel base layer. you can't weld to the chrome. A sanding disc or flap wheel won't due it. You need a stone grinding disc. If your not throwing sparks you are not through the chrome.

trikedoc
10-06-2012, 07:10 PM
I had planed to use the same chrome suspension fork on my Aurora build. I was going to put a piece of solid round stock in the top of the hollow lift fork tube. Drill and tap for heim joint pivot bolt. Didn't account for the extra length. the 14" front frame riser needed to be a couple inches longer.

oolieiv
10-06-2012, 11:56 PM
I was using a stone grinding disk, I was throwing sparks. I don't know what the heck is up with it, or if maybe I needed to grind the crome off the entire fork cause it being NEAR the weld without actually being involved was causing the issue.

trikedoc
10-07-2012, 08:21 AM
My only other though is they used high strength chrome molly tubing for the fork which needs to be tig welded and if I remember needs Argon as the shield gas. Did you have any trouble drilling for your bolt?

oolieiv
10-07-2012, 01:48 PM
Zero trouble drilling