Front Leg

[GolfWhiskeyHotel]

Working on a Gazelle,  replacing the front tyre I pull the tail down and check the front leg. It wobbles a bit . the leg itself (the inner tube) was chromed that's now gone in places, there is up and down "slop" I read about biscuits in the manual , does not say what they are. How are the bearings in the outer leg arranged?  Is it just a spring in a tube? Does anyone have a working drawing of the leg?  Any help much appreciated.

Thanks

GWH

[Blueadventures]

Have you looked at the drawings in the back of the manual I posted in the Skyfox section for Gazelles?

[spacesailor]

You can rechrome your tube .

( CAUGHT that sneaky A I at-it again ) .

spacesailor

[facthunter]

Chroming stuff can cause Hydrogen Embrittlement. Don't do it on load carrying parts unless treated properly post plating (and not long after).  Nev

[GolfWhiskeyHotel]

25 minutes ago, facthunter said:

Chroming stuff can cause Hydrogen Embrittlement. Don't do it on load carrying parts unless treated properly post plating (and not long after).  Nev

I get motorcycle fork legs hard chromed all the time. No problems there. About $200 per leg!  Leg is   ground -chromed -ground.......... they're experts

[GolfWhiskeyHotel]

14 hours ago, Blueadventures said:

Have you looked at the drawings in the back of the manual I posted in the Skyfox section for Gazelles?

I have printed the drawings but they're illegible, too small to help. I can see the bearing, its drawn mounted on the bare leg. Looks like its pinned to the outer sleeve , would that be correct? How about the discs that proved the springing? what are they?  I've got hard rubber bar from my Jodel u/c rebuild , Shore 70, it may be too hard. Thanks anyway. Cheers , Geoff

[facthunter]

GWH did you even try to check up anything before you wrote that your man is an expert and that Hydrogen embrittlement is not an issue?

   If he hasn't taken the trouble to do  a bit of research HE"S NOT an expert. Welding wet or stripping plating or even electroless plating can cause embrittlement Hydrogen in storage under pressure causes it in pipes and containing vessels This IS a safety matter regardless of whether some one you know doesn't bother about it. CASA had an extensive article on it. What you have said is irresponsible. I hope you can see that. Now i'm going to get another bloody argument that shouldn't be happening.  Nev

[pmccarthy]

7 hours ago, GolfWhiskeyHotel said:

I get motorcycle fork legs hard chromed all the time. No problems there. About $200 per leg!  Leg is   ground -chromed -ground.......... they're experts

I have it done too, they grind it centreless which is amazing to watch.

[facthunter]

It's NOT about the grinding technique or whether you are happy. with your motorbike forls. It's about Hydrogen embrittlement. How does the Brains trust here think THAT Issue should be handled?. This IS important because unless the problem has miraculously vanished chroming bit's of load carrying structure on Aircraft that fly, is a no no Unless they are Post plating heat treated and It's done properly. It's little different in principle to heat treating other alloys. It either meets the spec or it's not legal(or safe)  Nev

[onetrack]

Nev is on the money, listen to him, that's decades of experience talking. Hydrogen embrittlement IS a serious problem if the chrome plater is unaware of the stresses involved in the end use of the product - and it affects high grade steels more than low grade steels. As all aircraft use high grades of steel, it's important to get professional aviation advice on any chrome plating planned for aircraft components. CASA didn't produce the article about the problem just to fill empty pages.

[spacesailor]

Perhaps a litte leniency for us mortals .

Nothing on my aircraft is , or ever will be " tso " or compliant to aviation standards.

It's a home built ultralight weight aircraft . 

That has been no problems with ' nosewheel legs ' failing to my knowlede .

( I could ask if there has been a broken nose wheel leg ever ).

I was thinking of chroming my ' noseleg ' to fight rust on the wear parts ,after the grease has rubbed away . ( not high-grade steel ) .

spacesailor

 

 

 

[facthunter]

Why waste money  Chrome is porous.  Nev

Edited April 13 by facthunter

[spacesailor]

Chroming seems to be very hard wearing , and doesn't rust like bare metal .

But 

It is now, of this year banned  in all new car manufacturing. 

seems another " greening " of, what was, will never be again .

The ' world ' is in retro,  

We will soon back to the dark age of " horse & cart .

No coal,  burn tree's. 

Ne plastic bags , cut down more tree for " brown paper bags " .

No more IC omnibuses , back to " trams " .

instead of electrification of buses . ( no rails. needed ).

What a world to leave for our descendants . 

spacesailor

Edited April 13 by spacesailor
A I

[facthunter]

Au  contraire. Banning this stuff helps making the world we pass on to our descendants BETTER that it would otherwise be. That's close to being a "FACT FREE RANT" ol Boy.  CADMIUM is very toxic.  The approved Aviation Replacement for that is "ZINC-NICKEL. Hydrogen embrittlement can be treated appropriately but you need to actually DO something to achieve that. Nev

[spacesailor]

No chrome on my ' mild-steel leg ' .

 

 

 

p l

They were ( a couple of years ago well oiled ).

Just have to oil it annually. 

done , but no photo ,as hands now need ' de oil ing . LoL

spacesailor

 

 

 

[facthunter]

Good chrome was always rare. The Japanese and Italian bikes have pretty "ordinary"  stuff. British was once amongst the best. It's got to be looked after with covers and good polish.  Nev

[spacesailor]

ZI-NI Is not as hard wearing as chrome .

Which was my thinking before . " rust protection & wear resistance " .

If your 'Old ' leg has a little wear , & is a little sloppy '. 

The Plating could  be a metal builder . 

spacesailor

 

[facthunter]

It's not for wearing surfaces, It's for oil pipes. push rod tubes  nuts studs and bolts rocker covers'  steel oil pump bodies  drainplugs. etc  nev

[GolfWhiskeyHotel]

On 10/04/2024 at 3:48 PM, facthunter said:

GWH did you even try to check up anything before you wrote that your man is an expert and that Hydrogen embrittlement is not an issue?

   If he hasn't taken the trouble to do  a bit of research HE"S NOT an expert. Welding wet or stripping plating or even electroless plating can cause embrittlement Hydrogen in storage under pressure causes it in pipes and containing vessels This IS a safety matter regardless of whether some one you know doesn't bother about it. CASA had an extensive article on it. What you have said is irresponsible. I hope you can see that. Now i'm going to get another bloody argument that shouldn't be happening.  Nev

FFS . I have been in this eng. game for 60+ years. If I say he's and expert , he is , and that includes knowledge of embrittlement. ....I dont anticipate armchair commentators to start questioning my posts. Thank you.

[facthunter]

Pretty arrogant response Ol Mate. You have NO idea of my qualifications or experience. All I wish is for people "OUT THERE" to understand there IS an issue with Hydrogen embrittlement and you sort of indicated there wasn't.  It's a safety matter. Is it not.? Why don't you address the Points I made and IF you post here like everyone else here you are not immune from questioning of WHAT you post. Nev (not armchair commentator). 

[GolfWhiskeyHotel]

OK True.  .... NO IDEA of your qualifications or experiences........ Nor have you of mine. ........and I did     "Even Try"  ( your expression wound me up as it inferred lackadaisical behaviour )    to check yes....... And Hydrogen embrittlement is a well known phenomenon in the industry. However,  I  have dealt with thousands of fork legs and shafts and NEVER seen or heard of a fork leg suffering that type of breakage. Even under extreme usage. So while it  happens,  it's not common. 

 

However , I have had personal experience of a zinc plated special bolt 5/8" unf breaking at hand pressure!   High carbon steels ( with a hardness above 40 Rockwell)  are susceptible to cracking if not correctly heat treated after plating. 

[spacesailor]

So !

Is that embrittlement ,such a bad thing , on the ( inner )straight piece of the front leg ,  made of ' cheap mild-steel ' . It seems a good thing to stiffen that piece of pipe up . A bit,  instead of it being bendy. As well as "wear proofing " it a lot .

It's all made up, so cannot put a better ( tenstile ) part in , then weld it to the forks .

I have not made enquiries as to the pricing of said plating, ( for half the pipe length ).  It could be out of my ' pensioner ' pocket money .

spacesailor

 

[facthunter]

It makes it prone to fracture at low stress levels . It's NOT a surface thing. I had a crankshaft break on a race car before the motor got much above idle speed. Hadn't even been put in gear. Straight through a  2" big end journal. The crank had previously been crack tested and the chroming process was extremely expensive. The University of Technology  Newcastle annex was close by and they sorted the problem. This was in the mid 50's. WHY run unnecessary risks space? Learn by other's mistakes.  Nev

[Peasant_Pilot]

Have you got a photo of the front gear leg? @GolfWhiskeyHotel

 

Cheers

 

Rob

[spacesailor]

Because,  those legs do bend easily,  and that wear , plus the rusting on that area .

Is a known problem .

It's only a tiny aircraft , & I suspect the leg could be made just a little stronger. 

After a few years of having a ' training wheel ' at the front I was intending to change the ' Hummelbird ' to a conventional tail dagger,  eliminating the nose wheel problem.

spacesailor