DIY Eyepiece Camera to Reduction Lens Adapter

[desertrat]

Went out into the garage where all the tools and equipment are, and scrounged up a piece of aluminum round stock. Cut off a section with the Harbor Freight Tools cutoff saw. Shakes and rattles while it's running, but got the job done a lot quicker than using a hack saw.

Cutoff_saw.JPG (68.15 KiB) Viewed 5646 times

Chucked up the piece of aluminum in the old Atlas 12" long bed metal cutting lathe with quick change gearbox, and started drilling.

Drill1.JPG (65.18 KiB) Viewed 5646 times

Worked up to a 3/4" drill bit.

Drill2.JPG (70.47 KiB) Viewed 5646 times

[desertrat]

Then switched to the boring bar, bored the inside to three different diameters, then turned the boring bar around to the other end and used the internal thread cutter to cut the mating threads for C-mount connector on the reduction lens. I'm lucky the C-mount specification is old and American, and based on inch diameter and threads, because the lathe can't do metric threads without some modifications.

Bore_thread.JPG (59.43 KiB) Viewed 5642 times

Just as I was almost finished cutting the threads, noticed I had somehow screwed up and set the compound rest to the wrong angle.
The threads turned out ragged and ugly, but the reduction lens threaded in smoothly, no binding and wasn't loose or sloppy, either. If these parts were subjected to any significant mechanical load at all, I would have had to start over with a new workpiece. As it is, it isn't pretty, but it works. Next time I'll be more careful.

The finished part.

Adapter_finished.JPG (29.62 KiB) Viewed 5642 times

The cutter came from a kit of small high speed steel cutting tool blanks from Harbor Freight Tools, and I ground it by hand on the bench grinder. This actually made some nice looking threads on a previous project several years ago when I had the compound rest set to the correct angle. If a part is going to see heavy mechanical loads, the threads have to be very accurately cut to the correct form and dimensions, but these parts I've been making aren't subjected to any significant mechanical loads, so the cutter angles and form don't have to be critically accurate.

Thread_cutter.JPG (44.12 KiB) Viewed 5642 times

Those of you who are Journeyman machinists are probably getting a good chuckle by now. I picked up a little machining as a hobby and was never professionally instructed, so I'm probably doing a lot of things wrong. But it's been kind of fun, and once in a while I can make something that would be nearly impossible to obtain otherwise.

[desertrat]

Assembled the eyepiece camera to the reduction lens with the adapter. Slid these into the drawtube of the antique Spencer microscope, using an antique Spencer 370 illuminator lamped with a 25 watt tubular frosted lightbulb from the local hardware store.

Spencer_mono1.JPG (67.85 KiB) Viewed 5640 times

Took an image from a prepared slide of plankton from Wards Natural Science company. Banding from the AC powered lamp was very bad. Image taken through the antique brass 10x objective.

Diatoms_incandescent.jpg (50.39 KiB) Viewed 5640 times

Removed the 370 lamp and temporarily used a battery powered LED camping lantern for the light source.

Spencer_mono2.JPG (68.51 KiB) Viewed 5640 times

Took another image from a different section of the slide. Banding completely gone. Looks like smooth DC to power the lamp is the way to go here.

Diatoms_lantern.jpg (57.7 KiB) Viewed 5640 times

[viktor j nilsson]

Those of you who are Journeyman machinists are probably getting a good chuckle by now. I picked up a little machining as a hobby and was never professionally instructed, so I'm probably doing a lot of things wrong. But it's been kind of fun, and once in a while I can make something that would be nearly impossible to obtain otherwise.

This was a good read, thanks! Your workshop looks exactly as I imagine my shed would look like if I had one. Instead I'm forced to do all my work at the kitchen table at 1am, and try to find every single bit of aluminum chips on the kitchen floor before I go to bed so my 6 month old doesn't eat it in the morning. You're living (one of) my dreams!

[MicroBob]

Hi Rick,

you have a nice boring/threading setup there - very convenient! Did you make the shaft with the square hole yourself?
For threading one wants to cut in the direction the bed slide advances. One wants to take of a chip on the headstock side of the groove and make it a bit deeer at the same time. In Germany it is common to have the compound slide set longitudinal and you move the cross slide and compound slide a bit between passes. In the USA it seem more common to set the compound slide at an angle and just advance with this.
For aluminium it is important that the threading bit is shaped to bring the right angles in contact with the work piece. For this the grind has to be asymetrical. I can't see on your picture whether the grinding is already suitable.
I'm not trained machinist myself but I'm happy to do a bit of machine work at home and in the job. In my home workshop I have assembled very nice equipment over the decades. Practical capabilities are also good to pass on to the children because it is very satisfying to create something.
Right now I'm getting into 3D-printing which is a nice addition.

Bob

[desertrat]

Hi Bob,

I didn't make the boring bar. It was made by Armstrong, who also made the boring bar holder, cutting bit holders, and "rocker" style tool post. These are kind of considered antiques now. Harbor Freight Tools, an importer of Chinese made tools, used to sell replicas of these, and may still.