Flanged Bushings

[Douglas]

Hi sailors, I have a Forespar mast,,, it has many welded on fittings,,,, in particular, on this subject, the mast has 1/4" thick X 2" OD aluminum washers welded all around,,,, attached to the outside, mast wall sides as "doublers" thus thickening the mast wall which a tang through bolt, goes through with a "thin" wall aluminum compression tube in which is the ss through tang bolt, passes through.

These 1/4" X 2" aluminum washer-doublers has some advantages and some disadvantages too.

We would have to consult with a naval engineering architect to find the load tolerances that Tom P , refered to , but just ball parking , I was hoping to find a way to use flanged aluminum bushings instead of copying the Forespar system of welding on doublers .

Brion has pointed out previously that a compression tube is not needed, if the through bolt nut bottoms out during tightening, before compressing the sides of the mast . This I have carefully done .

I think it was Brian that clued me in , that the flanged bushings do not need to be screwed , rivited, welded, or even attached to the mast wall in any way .

I think what we are trying to do is, spread the down loading through bolt loads, onto a bigger diameter bushing,,, so that the tang through bolt doesn't "sea-saw" an elicpital hole in the mast wall, during use.

I have been trying to guess what size through the mast hole would provide an adequate bushing bearing surface for say a 1/2" and or a 5/8" ss through tang bolt.

If I was machineing a stepped flange, I just may guess that an aluminum bushing of 1" OD , with an 1/2" or 5/8" ID ,,,, might be sufficient for the small end of the stepped flange, where as, a 1/4" thick X 2" OD might be acceptable for the large end of the flange,,,,, yes ,,, you say ,,, but what about the plunge depth through the mast wall ? How about 5/16" on that shoulder ?

Currently, I have great problems trying to communicate instructions to the welders here,,,,, seems that multi lingual welders are not available,,,,, sooo I am trying to build a mast with a bare minimum of any welding on it,,,, thus using the stepped bushing idea, instead of welding on doublers.

You ought to see the trouble I am having with my shieve box !!!!!!!!!!

Thank You Guys , for your help and patience,,,, counting to ten has helped me .

Douglas