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herb capsule maker help please


May 2, 2005
ridgecrest, ca
Recently I completed a project where I designed and built a device to fill herb capsules. With some help from this forum and persistence I was successful. With it I can orient, separate, fill, tamp, and close thirty small gelatin capsules at a time.

Here's the problem I now have. I built the device with a combination of Starett low carbon ground stock (1018) and polycarbonate. Before and after use the device must be carefully cleaned. Left without protection, the 1018 will rust within a day or two. So here's the process: Clean, make capsules, clean, oil, then store. The cleaning is taking a couple hours as I must ensure zero contamination.

The poly is fine. I need to replace the 1018 with some kind of stainless. When I built the device I had a fit trying to cut the 1018 with an acceptable finish. Several 3/8 plates with 30 holes, two of the plates with stepped holes with a tolerance of .0005 to .001. The capsule walls are .004-.005 thick and delicate.

Recommendations requested for stainless steel that machines with a superior finish, can be cleaned with warm water and soap, air dried, and stored without rusting.

Second request. My first design used 1/4 ground dowels for alignment of the plates. The plates are 4X5", 3/8 thick. The 1/4 dowels jam easily when the plates are installed and removed as part of filling the capsules. What would be the proper size for the alignment dowels for smooth, jam free operation?

Thanks in advance

Mike, couple ideas relative to the dowel pins. If you go smaller, the system may be less likely to jam but more likely to break a dowel pin and that's no good.

Have you considered bullet-nose pins and bushings? I think they are available from Reid Tool. Not sure about the availability of stainless versions of those, tho.

316 is probably going to be your best bet. It machines well, for stainless, and about a corrosion resistant as they come. 303 machines really well but it is only so-so when it comes to rust. 416 machines like butter but it will rust so easily I don't even understand why they call it stainless.

Do you have to use stainless? Could you use aluminum? I use 6020 on lots of marine instrumentation parts. 7 months over hot salt spray and nary a bit of corrosion. It is lead free, called Ultr-Alloy by Alcoa, and takes anodizing very well. Problem is I can't find a vendor that sells smallish lots of anything other than round stock.
Dowel Pins.......change all but one to a diamond pin. The diamond shape drastically cuts down on the bearing surface that is causing your binding. Cut the diamond so that you only have original diameter of the pin on 2 sides. We usually cut a flat at 0',60',180' and 240'. This leaves a small bearing area.

Material.....try 316 if you must use stainless but if you can get by with aluminum we regularly spec 2024 aluminum with a .0004 to .0006 thick electroless nickel heat treated. We get excellent wear and corrosion resistant surface.
have you thought about nickel or chrome plating all the steel parts ?Maybe cheaper than starting over in s/s.
I really appreciate the posts!!! Lots to think about. When I get off work tonight I will respond more specifically. On first read, I would like to use all of the suggestions! This is a great forum.