Since deciding I wanted to start a DYI Equatorial Mount for my budding astrophotography career, I have been going searching for parts. As luck would have it, my brother was rebuilding his patio and gave me a mount for his old satellite dish antennae. The piece is not perfect, but it will serve nicely as a screw mount adjustable wedge to align the mount with the polar access. The base of the unit was not useful for my purposes and it seems quite study.
The next pieces I need to purchase where four pillow blocks which I found from our good friends at Amazon.com for about $24. The pillow blocks I ordered where for a 1 inch axle and when they arrive, I measured them at 0.950 inches. The pillow blocks seem to be well built and once I had them in hand, I began to question the overall weight on this project.
For the axle shafts themselves, I picked them up for $17 from a local company here in Vegas called Curtis Steel. I purchase two feet of cold rolled steel at 1.25 inches in diameter. This should give me 0.30 inches of material to find the center and cut down the axles.
Turning the Axles
Fortunately, my South Bend was up to the task and the new tool holder cut down on the chatter. I was able to turn 0.025 inches off the radius with no issues. Turning this amount off introduced quite a bit of heat into the project. So, after two passes I swapped the project steel out and let it cook while I tuned the second bar down. I was overall very happy with the performance and once down to 1.140 inches, I drop to cuts down to 0.005 so that I did not overshoot the inner diameter of the pillow block. I was intent on making these axles complete fill the pillow bock bearing so that they are true and will find there centers.
I was being very cautious of not over shooting my destination diameter of 0.950 inches in order to keep a very tight fit. Once I turned the axles down to 1.000 I opted to take the last little bit of material down using a file and then 100 grit sand paper. After a few minutes of work with each, I would stop progress and measure and attempt to fit the bearings.
Once I was complete with the two axles I did a quick tested and confirmed that at this pint, the weight of my DYI Equatorial Mount is going to be an issue. Up until this point in time, I was planning on using two equal length axles. I have adjusted my plans to shorten the bar on the declination axis. Additionally, I am thinking that I may mount the pillow bearings on plate aluminum rather than steel.
There is also little doubt in my mind that boring on whole down the axis of each bearing should remove quite a bit of weight and still maintain some strength within the system. Previously, I was planning on drilling out the right ascension axle to assist with polar alignment. I am now thinking about going 0.5 inches over the originally planned for 3/8 of on inch and doing this with both axis.
I do realize that this DYI Equatorial Mount is probably overkill and over build for my purposes. However, to date, I have spent $41 dollars and am quite enjoying the project.