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Author Topic: Thrust Bearings for Rohn 45 tower  (Read 1652 times)
W4DNR
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Posts: 3




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« on: October 04, 2012, 08:56:44 AM »

I need a couple of thrust bearings . One at the top of a Rohn 45 and one at the accessory plate above the TX-2 to allow
rotor removal without having to lift the mast .  A couple of hundred pounds of downthrust at most.  I can't see buying $360 dollars worth of TB-3 s. Has anyone had any sucess homebrewing ?  I'm thinking thick teflon or nylon slippery surface between a couple of 12 inch diameter steel plates ..... no lube or ball bearings to rust.   Any suggestions ?

Thanks Guys.

Don W4DNR
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W1AN
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Posts: 11




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« Reply #1 on: October 06, 2012, 03:42:23 PM »

Hi Don. Many years ago we would saw and drill out pieces of 3/4" plywood to take the place of a thrust bearing.  Wood preservative would help it last for a few years. A superior material to use today would be 3/4" PVC trim board.  If you want to install around your mast in position, simply saw across the piece to split in two halves. Two bolts on each side should hold well. No metal is needed. This arrangement  provides a bushing surface only. To hold the mast in position to remove the rotor, you can use a piece of angle iron and a U bolt secured on the mast tightly above the lower PVC bushing. Drill the angle so that another u-bolt can secure it to a tower leg to prevent the mast from rotating while the rotor is out.

In my opinion the TB3s are a good investment. They last a long time and you know the job is done right. Look around for better pricing.

73,
John W1AN

« Last Edit: October 06, 2012, 03:46:36 PM by W1AN » Logged
W8JI
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« Reply #2 on: October 06, 2012, 04:36:57 PM »

I need a couple of thrust bearings . One at the top of a Rohn 45 and one at the accessory plate above the TX-2 to allow
rotor removal without having to lift the mast .  A couple of hundred pounds of downthrust at most.  I can't see buying $360 dollars worth of TB-3 s. Has anyone had any sucess homebrewing ?  I'm thinking thick teflon or nylon slippery surface between a couple of 12 inch diameter steel plates ..... no lube or ball bearings to rust.   Any suggestions ?

Thanks Guys.

Don W4DNR

Why would anyone use two thrust bearings? Seems to me that is just asking for binding and stress problems on the rotor.

The bottom of the mast should be guided only by the rotor. Otherwise the slightest misalignment will bind things up.

A slip system at the top is fine. I've used PVC, Nylon, and Teflon over the years.

Install a muffler clamp up there, and you can use it to prevent the mast from dropping if the rotor is removed.

73 Tom
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N0GRM
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« Reply #3 on: October 09, 2012, 06:08:07 AM »

Don - It appears I may be close to the same stage of tower installation. 

Quick question, on which section had you considered installing the TB-3?  I'm modifying section two with the BXT2A top plate.  Unfortunately, I can't find documentation that indicates the TB-3 will attach to the BXT2A, nor can I find drawings with dimensions. 

All -

Will the TB-3 work with the BXT2?

Converting BX40 to HBX32

Thanks -
73' Peter N0GRM
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