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Repairing the Warner and Swasey Mount at Washington University

It is listed as either a 6" or a 6-1/2". It was made by Fitz; then the Clarks reground it. I measured it, and it is 6-1/4". 

I was called to repair the Warner-Swasey mount at Washing University.  I first went over Dec. 9, 1999. I met representatives and they related the problems with the mount as:

 The Right Ascension clutch would no longer engage and lock.

 The original pendulum clock drive had been replaced "about 30 years ago" with an electric motor. The spiral gear had a habit of stripping the teeth occasionally.

This was almost, but not, a complete restoration: I only did necessary repairs to enable the observer to lock the R.A. axis, and restore electric motor functionality. As it turned out, it seemed many things needed attention to make the mount function as designed.

I took the mount home with me to my shop, where I could inspect and make whatever parts would be necessary. I was told that the scope and mount had not been taken apart for at least twenty years. The controls were removed first, as they were connected to the mount and the tube. First inspection showed the declination to indeed be frozen and non moveable. The tube assembly is made from bolted steel, and was rather difficult to remove, as it was heavy and awkward. It had a round access plate in the middle, opposite the saddle. I had some trouble removing it, as evidently some rain had seeped in and dropped on the scope. This caused some rust around this plate, and in various other places, as noted below. There was also some paint and other debris which prevented the piece from coming out as smoothly as I had hoped it would.  There were a few tense looks from the onlookers as I hammered on the piece to get it broke loose! After removing the plate, the bolts holding the scope to the plate were removed. The tube assembly was also hard to remove, as the dirt, rust, paint, and solidified grease had made a tight fit between the base and the scope. We then removed the mount from the pier, and took to an inside room in the University. I then took the shaft housings off, and separated the shaft assembly from the mount base. It was then much easier to haul it to the ground level.


The motor is a 10 RPM reversible Bodine motor. There was a hole in the electrical junction box which was plugged. I added a three way switch so the motor can be started, stopped, and reversed. The contacts on the cord switch were pretty well pitted, and would not maintain good electrical contact. The motor is connected to the mount via a 1/4" shaft to a spiral gear assembly in an  aluminum box, which I learned had been made at the University shop. They had changed the spiral gear a few times, too. The shaft has a worm on it which engages the spiral gear in the housing. The main worm drive for the mount has a 5/16" hole through it long ways. Another shaft which has the spiral gear mounted on it goes through this hole.  The first thing I noticed was the shaft for the spiral gear was approximately 1/16" out of true. This is more than enough to cause the gears to wear out, so I made a new shaft was made from Stainless Steel. The old shaft (the one out of true) was approximately 5/16", to fit the gear. There were two spacers (about 1" long, 1/2" I.D. x ~5/16" O.D.) The new shaft is 5/16" O.D. and has the ends ground down to fit. This should keep the shaft centered and keep wear on the spiral gear down to a minimum. The small piece in the access plate had a bonus - it was a small mirror you can turn, to inspect the inside of the tube assembly. This too has not been used. It was bent, greasy, and rusty. I polished it and put in in the correct position.

A base plate of aluminum was attached to the mount base. The motor was mounted on an aluminum plate, which was held to the base plate with four screws. 

 There were four springs between the two plates, evidently to allow the motor to line up correctly. After removing the electric motor, I saw where there had been a few attempts to drill and tap holes in the side of the mount. There were a couple of places where the tap had broken off. I removed the springs, changed the screws, and mounted the motor directly to the base plate, using brass bolts. One of the holes in the base plate was slightly off center, so I milled the holes in the base plate a little larger to enable the screws to fit flush in the plate. I cut the new shaft approximately �" shorter than the old one. The end still fits in the outboard bearing, but does not stick through now. I made a small cover plate to protect the end of the shaft. This keeps the end of the shaft from sticking out. I also removed the flimsy piece of metal that was under the altitude adjusting lock nut. This piece of metal was apparently bent to hold the aluminum box from moving and throwing the gearing out of alignment. I made a new bracket that mounts on the electric motor base plate. This holds the aluminum frame securely.


One wood knob was gone. Another was bent. I installed four new ones. The brass ring they screw into had been worked on a few times. The bolts were 3 different threads, and two of them were stripped. I drilled one out to about 1/2" and plugged it with a brass plug. I then drilled and tapped all four holes for 5/16" x 18 threads.

Other notes

Removing the many parts on the shafts was difficult, as there was rust in several places. There was also years of accumulated dirt, dried up old grease and oil, and many places where black paint kept things from moving. The setting circles were removed, and the collar. The brass collar had considerable rust in it. I got to the declination clutch,  which is located where the two shafts intersect. The problem with the clutch seemed to be  from three distinct causes. First, a hole had been drilled through the housing. Some small pieces of metal shavings were present. Second, old grease and oil had dried up, and the resulting gunk was really heavily imbedded in all crevices. Third, the clutch rod engages the gear nest assembly, which in turn rotates a short shaft that tightens or loosens the lock assembly as needed.  This short shaft has threads on the end which screws into the actual brake which is comprised of two circular pieces which have a radius cut to match the end of the shaft. The one with the internal threads had considerable wear, and would not come down far enough into the housing to contact the end of the shaft. I removed the gear nest assembly, and then all parts of the upper section of the mount were taken apart. I noticed almost the parts have a small 2 on them. I chucked the round piece for the lock in the lathe and removed a few thousandths from the lower end. This kept the radius the same, and will allow the rod to tighten the two pieces enough to provide plenty of locking. The gear assembly itself was also a problem. I tried to  turn it by hand, but it was really stiff. Plus, every revolution it locked up and "jumped" up. I took the whole assembly apart and thoroughly cleaned it. I found one of the screws that hold the nest together was broken off in the hole. Someone had unsuccessfully tried to remove it. I drilled a hole in it, and removed it. I then made a new brass bolt to dimensions. I checked the bevel gears, and found some of the ends had been burred over, evidently from trying to force the declination brake to tighten and lock. I chucked up the gear assemblies, and touched up the ends of the bevel gears. I also stoned down the spots where the hole had been drilled. After another cleaning, and light greasing, the gear assembly now turns easily and there are no tight spots. After assembly, the R.A. axis locks very easily by hand, so it should be real easy with the control knob.

I touched up the bare places on the mount and shafts with standard gloss black enamel. I touched up other paint nicks after mount was installed. I cleaned everything, and touched up the missing red paint, also. The brass was not polished, but was cleaned of all old grease and paint. The four small micrometer eyepieces were really dirty. Evidently they are not used.  One of the small micrometer plates with the markings is missing. The inside of the bearing housings on the base of the mount have been scarred and scratched from years of dirt and whatever. I used emery paper to smooth rough places. All four oil bearing covers were cleaned back to brass (they were painted black) to allow them to be easier to locate. The old grease was very hard, and I saved some in a small container, along with all old parts. I made a thin Teflon washer to go between the two bevel gears on the control shaft. There was some wear to everything and the washer was just enough to take up the slack. This will also help keep the two gears separated so they will not create burrs on the ends of the large bevel gears again. I also supplied a small amount of lubricant to use in the oil holes.

December 25, 1999. The mount is assembled now, and almost ready to take back to the Observatory. I made a few more bolts to replace ones which are stripped or have the ends messed up.

January 6, 2000. Took the mount back and installed it. Everything went together a lot easier than it came apart, no doubt to the fact it was all clean and lubricated now.