[TowerTalk] HG70HD pulley

[Roger (K8RI) on TT]

On 2/6/2014 11:14 AM, Patrick Greenlee wrote:

Is it a bushing or a bearing?
I would advise against removing a pressed on bearing, or bushing by 
tapping on small spots as there is no guarantee the bearing or bushing 
will cone out straight and if it doesn't it can distort the hole into 
which it was pressed, sometimes drastically. The narrower the bearing 
the more likely it will tip. If the pulley is of a soft material such as 
aluminum (which it probably is), it can easily be damaged and make the 
hole "out of round". This seems simple, but it takes skill and if 
expensive and difficult to replace, not a good place to learn.  Pat's 
suggestion for using a socket to press the bearing in is also a good way 
to press one out. Instead of larger you just need a socket who's OD is 
slightly smaller than the bearings OD (I prefer a deep well socket). For 
some, it's easy and hard for others. Not all of us are mechanically 
inclined. I was raised on a farm where we did our own repair work and 
improvisation was the word of the day.  We rebuilt an old threshing 
machine into a combine.

A much simpler approach is to take an Aluminum dowel, 3 or 4" long and 
slightly smaller than the OD of the bearing/bushing. Make sure the face 
is flat and perpendicular to the long axis of the dowel. Carefully keep 
the face flat against the bearing/bushing and tap on the back end of the 
dowel.  If the bearing has a raised center, just drill out ted center of 
the dowel enough to clear the raised part.  You could "probably" get a 
machinist to face off the ends of a 3 or 4" dowel for a couple of bucks.
Know a friend who owns a lathe? Facing a dowel isn't precision work.   
This should easily remove a pressed in bearing or bushing.  The hole and 
bearing are an interference fit. If it's a bushing, as a last resort a 
new one can be made of oilite. Remember it's an interference fit, even 
oversize by a Little will cause the ID to change when pressed in. Then 
you have to ream the ID with an adjustable reamer. Check prices of 
adjustable reamers on Grizzly.com!  If you don't have the equipment or 
skill, find a good machinist.

There are many ways to make a simple press, but although simple it'd 
take more than the many words I've already used.

73 and good luck

Roger (K8RI)

> It is likely but not a certainty that the bearing is pressed on and 
> will need to be pressed off or pulled with a bearing/pulley puller.  
> If you elect to try to pry it off do go around and around making just 
> a little progress on each "bite" and be patient if it takes many 
> revolutions.  Most likely there will be a number on the bearing that 
> you can use to secure a replacement. If no number then take the 
> bearing with you to Graingers or other similar vendor or an auto parts 
> store.  You need to match the size exactly to make it fit properly.  
> If you have a number then Google it to find sources. Mind the load 
> ratings and do not use a bearing not up to the task. Leave a good 
> safety margin even if it costs a few bucks more.
>
> If you install the bearing yourself be careful to not cock it when 
> inserting it.  You can select a socket from your socket wrench set to 
> use as a tool to press (tap with a hammer or squeeze in a vise) the 
> bearing into place.  The socket you select should fit such that all 
> the force you apply to the socket presses on the part of the bearing 
> in contact with the pulley and does not touch the part where the balls 
> are.
>
> If you use a hammer or a vise (or hydraulic press if available) you 
> should press a little then rotate the pulley part of a turn and press 
> again. This will help prevent cocking the bearing. The farther in the 
> bearing is pressed the less important the rotating becomes.  Rotating 
> is the most important when getting the bearing started. Look at it 
> closely when getting the bearing started and make corrections early on 
> before pressing the bearing even 1/4 of the way home.
>
> Hey, it is easier than my comments may make it seem.  I have done it 
> successfully and I am strictly self taught in mechanic stuff.
>
> If you have additional questions or concerns that you would want to 
> send direct, I am good in QRZ.
>
> 73,
>
> Patrick NJ5G
>
> -----Original Message----- From: Mike Reublin NF4L
> Sent: Thursday, February 06, 2014 9:37 AM
> To: towertalk reflector
> Subject: [TowerTalk] HG70HD pulley
>
> While working on getting the new puppy ready for duty, I discovered 
> the pulley at the top of the main section would not turn. I soaked it 
> with PB Blaster and got it to go maybe 1/8 turn.
>
> I took it out, cleaned it well, put a little grease in the hole and 
> put it back in. There is quite a bit of slop now on the axle.
>
> Did I lose part of a bearing? Any suggestions for a fix or replacement?
>
> 73, Mike NF4L
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