• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

Scott 3200 Bearings

A trick to remove a race or bushing that's pressed into a blind hole is to weld on it from the inside. The heat will make it try to expand, but because it's hot it will plastically deform to a smaller diameter. Let it all cool and the race will essentially fall out. Weld rapidly with a fairly high heat. The idea is to heat the race much more than the surrounding casting.
 
A trick to remove a race or bushing that's pressed into a blind hole is to weld on it from the inside. The heat will make it try to expand, but because it's hot it will plastically deform to a smaller diameter. Let it all cool and the race will essentially fall out. Weld rapidly with a fairly high heat. The idea is to heat the race much more than the surrounding casting.

never been brave enough to try that in an aluminum casting......
 
What Geezer said, did it all the time on truck wheels. Will work on Alu. housings also, no problem

Tim
 
As far a certified parts are concerned there is a FAR called FAR21.303(b). Which stated the owner can produce or supply his own parts for his own aircraft.( GO read the FAR as I am sure it's paraphrased here). If an owner brought me a set of bearings and they were timkin with the correct #s and he said they were good bearings (owner purchases part and does inspection, performs the Quality Control function) I can install them and sign them off (at my discression if they are good parts) as "installed owner supplied parts P/N ...... in ..... IAW the limitations of FAR 21.303(b), unit ops. checks good" or similar statement and be completely legal in the eyes of the FAA ADMINISTRATOR. The key for this FAR to work is the owner has to be involved- owner buys part, inspects part, buys material, installs part fabricated, fabricates part, assists in some way. Otherwise how could an A&P fabricate a new piece of engine baffling or a hose legaly? He does not have a PMA for the hose even though he assembled it from approved parts. When he assembled the hose he manufactured it if he sold it to an owner for a certified aircraft. ( I see a big FAA spanking on the way!!!) Now if the A&P only replaced one fitting and the hose, that's a repair!!!! So our buearacrats have decided for us (because they know best) that a repaired hose with one old fitting is better than a new hose with 2 new fittings without paperwork cause w/o paperwork the part is "bogus" and we all know bogus parts are bad!!!.. As usual the blame will always fall back of the mechanic who has a licence the feds can go after. The bottom line is the mechanic is on the front line for the aviation safety programs and FAR's to work as the feds can't come out and repair the aviation fleet themselves and must rely on the trust of the mechanic to do things properly and follow the FAR's.
Now that being said, it does not mean the owner can have me install a Holly 4 barrel carburetor on his IO-520 continental, that would be an alteration and is not within the scope of FAR 21.303.
This is why I love the freedom of experimental aircraft. We can do what we know will work and be safe without having to deal with all of the FAR's that are written for all certified aircraft especially aircarrier types.
 
So there's no "Scott" special instructions on to remove that particular bearing. It is showing some pitting but still servicable. Doesn't make sense. I can figure something but be nice to know how he factory does it or did it. The factory should chime in any time.
 
The factory built them but never rebuilt them. AK Bushwheels can rebuild it for you. I would not find a pitted bearing at all serviceable. I would TIG weld a big washer to it and knock it out.
 
As far a certified parts are concerned there is a FAR called FAR21.303(b). Which stated the owner can produce or supply his own parts for his own aircraft.( GO read the FAR as I am sure it's paraphrased here). If an owner brought me a set of bearings and they were timkin with the correct #s and he said they were good bearings (owner purchases part and does inspection, performs the Quality Control function) I can install them and sign them off (at my discression if they are good parts) as "installed owner supplied parts P/N ...... in ..... IAW the limitations of FAR 21.303(b), unit ops. checks good" or similar statement and be completely legal in the eyes of the FAA ADMINISTRATOR. The key for this FAR to work is the owner has to be involved- owner buys part, inspects part, buys material, installs part fabricated, fabricates part, assists in some way. Otherwise how could an A&P fabricate a new piece of engine baffling or a hose legaly? He does not have a PMA for the hose even though he assembled it from approved parts. When he assembled the hose he manufactured it if he sold it to an owner for a certified aircraft. ( I see a big FAA spanking on the way!!!) Now if the A&P only replaced one fitting and the hose, that's a repair!!!! So our buearacrats have decided for us (because they know best) that a repaired hose with one old fitting is better than a new hose with 2 new fittings without paperwork cause w/o paperwork the part is "bogus" and we all know bogus parts are bad!!!.. As usual the blame will always fall back of the mechanic who has a licence the feds can go after. The bottom line is the mechanic is on the front line for the aviation safety programs and FAR's to work as the feds can't come out and repair the aviation fleet themselves and must rely on the trust of the mechanic to do things properly and follow the FAR's.
Now that being said, it does not mean the owner can have me install a Holly 4 barrel carburetor on his IO-520 continental, that would be an alteration and is not within the scope of FAR 21.303.
This is why I love the freedom of experimental aircraft. We can do what we know will work and be safe without having to deal with all of the FAR's that are written for all certified aircraft especially aircarrier types.

An owner buying a bearing at NAPA and handing to his mechanic doesn't even come close to compliance with the standards for owner produced parts.

For your consideration, this article provides information and entertainment.
http://www.aircraftrebuilder.com/in...owner-produced-parts&catid=27:parts&Itemid=29

Stewart
 
Not really pitting Steve, you know those little lines sometimes the bearings leave, it runs smooth in the race and it really would be Ok for a while , but I guess I need to learn how to tig. I was hoping there was a method that was discribed by the people who make it.
 
Not really pitting Steve, you know those little lines sometimes the bearings leave, it runs smooth in the race and it really would be Ok for a while , but I guess I need to learn how to tig. I was hoping there was a method that was discribed by the people who make it.

Water marks. I would replace if on the wheel bearing race but the head doesn't turn fast. I am sure Scott would say replace the whole head assembly. $$$ Maybe Wup will chime in with some words of wisdom.
 
Stewart, That is a great article by Bill O'Brien and right on. I have that one saved from AMT magazine years ago. Bill was a great man and the whole reason I read that magazine for years. He did a lot for all of us that most will never know about.
 
Water marks. I would replace if on the wheel bearing race but the head doesn't turn fast. I am sure Scott would say replace the whole head assembly. $$$ Maybe Wup will chime in with some words of wisdom.

Just for you guys... about 4 quick beads and the race almost falls out I will post picts shortly


All I did was 4 beads and witha punch and a small hammer lightly tapped (see pushed hard) on the protruding weld from inside the bore and pushed the race out
 

Attachments

  • IMG_3672.JPG
    IMG_3672.JPG
    231 KB · Views: 176
  • IMG_3674.JPG
    IMG_3674.JPG
    346.4 KB · Views: 152
  • IMG_3676.JPG
    IMG_3676.JPG
    244.5 KB · Views: 163
Last edited:
Wup, My races looked just like this on my wheel halves. I figured it was from a period of inactivity from where the bearing sat on the race. I purchased my new ones from you with bearings. I pounded my old ones out the old fashioned way. I learned something new just now.
 
Cool, I learned something today. I never would have considered getting a welder any where near the wheel assembly. I use a hydraulic press to remove and replace the races.
 
Sorry to bring this back from the dead...I was searching google for these bearings and this thread popped up. The Lang 501A tailwheel uses the same bearings. I was able to remove the race pretty easily using a 3/4" socket on my 4-way tire tool and a hammer...it came out with a few taps.

Oreilly's Auto Parts has these bearings, supposedly they are Timken but they couldn't confirm that they are made in the USA until they arrived. $33 for the bearing and race. Not bad if they are made in USA...if not, I'll get them somewhere else. The made in USA Timken bearings I have are probably 40 years old, they have very minor rust in a few spots, and that is due to neglect/not re-packing at least every couple of years. I see no reason to go to something possibly of lower quality, and I'd hate to no longer have the option to buy a US made bearing, so I'll stick with Timken.
 
Be sure to check the dimensions. The bearings made overseas use the metric system vs inches. Very slight differences could make for a loose fit.
 
For what it's worth, the bearing Oreilly's had were National brand, made in Japan.

I found two new made in USA Timken bearings and two races on Ebay for $50 shipped, so I went with those.
 
21.303 became 21. 9 about 3 years ago, it defines what constitutes an aircraft part. 21.305 became 21.8, which states that if any part needs approval other than PMA etc, it can be approved "in any other manner approved by the FAA". AC21.29 tries to explain these two regs... it states that...
(8) Produced as standard parts that conform to established industry or U.S. specifications (refer to definition in subparagraph 3l, Standard Part).

NOTE: Standard parts are not required to be produced under FAA approval; therefore, it is incumbent upon the installer (and the producer) to determine that the part conforms. The part must be identified as part of the approved type design or found to be acceptable for installation under part 43. Refer to the AC 20-62 for additional guidance on this matter
this AC and a couple others (sorry, don't remember the numbers right now) give us quite a bit of latitude to use readily available standard parts, as long as they are pretty much the same as the OEM. even electrical,,, everything up to programmable devices is ok... you can go to Radio Shack and buy a 3055 transistor for your Cessna dimmer.... no problem. on the other hand... replacing an altimeter or airspeed, or other required instrument must be TSO, but that's a whole nother question isn't it. and yes I can quote regs
 
Last edited:
I thought the post was interesting bc it mentions the Aviation Grade of the A4050 was the A4050-20629

I would call McFarland and ask for the regulation they mention.

4846a4d229c69a7d23bba614fd4397ff.jpg



Sent from my iPad using Tapatalk Pro
 
Back
Top