Friday, April 20, 2018

Back Into The Backyard Workshop.

Some three decades ago I was finishing up a ten year stint at a large valve manufacturer and my employer made a gift to me of a surplus 8" x 16" sch. 80 pipe reducer along with an 8" sch. 80 pipe end cap. My intent at the time was to weld them together and make a large bell. This was something I had done a few times before on a smaller scale.

4" x 8" hanging on  simple angle bracket.
This 4" x 8" sch. 80 bell presently hangs on the side of my work shop. It is in need of some sanding and a new coat of paint but that will have to wait until other things are finished.

I also did a larger 6" x 12" sch. 40 that was donated to the church I was attending at the time and is used as the call to service bell. But as the old saying goes, life is what happens when you're planning to do other things and these parts languished in my storage building until last year when this project finally began.

The first step of course was to sit down at the computer and come up with a working design that I fully expected to refine as the job progressed. I decided early on that this was going to be a highly finished piece with pivot arms and a counterweight as is often seen with steeple bells.

One thing I do not have in my shop is a welder. Otherwise I would have done the welding myself. Fortunately I have a neighbor down the block who is a welding instructor at the local community college and I was able to persuade him to do the welding for me.

The tedious grinding and polishing begins.
The first step after I got the weldment back was to begin the grinding and polishing of the raw and welded forgings to a smooth clean finish. I started with an 80 grit hard disk and a soft touch to blend in the weld and remove all the remaining mill coating and scale. This alone was a two day process. I then progressed to an 80 grit soft disk to get down to where the smaller in perfections and pits in the surface were revealed.

Lots of fine detail work.
These places and the surface scratches left by the grinding wheels were then chased out with both a random orbit and a vibrating hand sander. I had to take special care to also remove the areas surrounding these pits at the same time so as not to create flat spots that would stand out on the finished surface.

The finished
polished surface.
This became an almost never-ending process of chasing smaller and smaller imperfections and scratches. I finally opted with mounting the bell onto a 4" x 4" post attached to my work bench. This made manipulating the bell much easier and allowed me to reflect light off of it from different directions making seeing where more work was needed easier as well.

It was now time to move on to what I call the counterweight pivot block assembly.

Counterweight assembly
before attaching pivot arms.
This was made from 4" x 4" fence post timbers with 1/4" steel plates sandwiched between them.  These plates provide added weight and stiffness to the assembly.

Sandwich plates with several
coats of self-etching primer paint.
There are two 3/8-16 x 5-1/2" long hex head bolts holding the long top plate to the long timber. Six long pieces of 3/8-16 all thread were then used to hold the completed sub-assembly together.

This assembly will be revisited after other other structures are completed.

This final assembly required careful fitting and
squaring up using half a dozen clamps.
Next came the mounting frame assembly. This consists of two A-frame sub assemblies, two runner sub assemblies that tie them together and an X-frame sub assembly. This X-frame will minimize any racking caused by the 110+ pounds of bell and counterweight swinging back and forth.

This assembly was made from standard 2" x 4"s, 1" boards cut to various widths along with two pieces of 3/8" plywood cut into matching octagons holding the X-frame together. All these pieces were assembled with wood glue and deck screws. All the openings and gaps were filled with plastic wood. The finished sub-assemblies and final assembly were sanded smooth with 80 grit then 100 and finally 120 grit sandpaper.

Aluminum pillow blocks
with bronze sleeves.
1" spherical bearings are used to mount the bell/counterweight assembly. This eliminates any minor misalignment issues with the pivot shafts.

Clapper ball with loop and
Bell mounting 3/4" eye bolt.
The clapper for ringing the bell is made from a 1-7/8" forged steel ball bearing. This is welded to a piece of 3/8" round bar that hooks through an eye bolt inside the top of the bell. The small eye welded to the bottom end is so the bell can be rung softly without rocking the whole assembly.

Initial fit up for alignment and balance checking.
Initial fit up was completed to check alignment and balance before staining, applying multiple coats of Spar Varnish to the frame and counterweight and clear enamel to the bell.



























The as designed center of gravity came in right on target at just under one inch below the centerline of the pivot shafts. The bell swings with ease and very little effort.

3 comments:

  1. It certainly looks like a labor of love!

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    Replies
    1. It is! I'll be posting more pictures when I get all the varnishing and outdoor set up complete. Marine varnish take narly a day to dry between coats. They recommend three coats but I'm going to do at least five and then an light sanding before the final two. It's not like doing French Laquer on furniture that dries quickly and let's you do several coats in a single day. So "slow and steady wins the race" will have to be the method.

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