Lets talk some more about drilling the hole through the barrel. As I said I do not drill this hole from one end but rather from both ends. To digress a bit I failed to state that after turning the barrel to 2 inches I chuck it into the lathe chuck. This necessitates getting it running true in the chuck. Now I drill half way through. Turn around and Re chuck the piece and drill until I meet the hole from the other end. There will be some mismatch but it will be provided it isn’t to much. With the barrel being 2 inches in diameter chuck jaw marks are not a worry we have one last finishing turn to do and any marks will go away.
To start the final turning operations I make a dummy plug to fit the hole in the barrel with slight resistance to going in. This will support the end of the barrel, when the tailstock live center point is forced into the end.
To finish turn I make a friction mandrel by chucking a scrap piece of wood about 3 ½ inches long and 2 1/2 inches in diameter into the chuck. I turn this piece of wood back about 2 inches to fit the hole in the barrel this must be a snug friction fit so I usually make small cuts until I get very close then out comes the 80 grit to 100 grit sandpaper and I sand it down until the barrel will slide over it to the shoulder. This fit needs to be fairly tight but not so much that you can’t get it back off later when finished.
Now I slide the barrel onto this mandrel and insert the plug into the tailstock end and tighten the tailstock live center into the plug until it forces the barrel against the shoulder on the mandrel. The final sizing and finishing can now be done. Here is when close attention to precision comes into play. The outside of the barrel must be turned the full length to slightly under 1 ¾ inches in diameter. That is if you plan to spray it with clear lacquer or some other clear finish. My scopes after sanding thru 400 grit paper are coated with 6 or 7 coats of clear lacquer.
My scopes have a rotating object cell housing on them so the person viewing the image can rotate the housing without having to rotate the whole scope to make the image do it’s magic. This has always held a sense of wonderment for people as to how I do this without the housing pulling off. Well here is the secret. I use a coated wire locking mechanism to retain the housing. The wire I use is 1/8 diameter and what I do is I cut a groove a little more than the wire is wide and deep enough that it is completely below the out side diameter of the barrel. I cut a piece of wire long enough to wrap all the way around the barrel but short enough that it doesn’t have both ends meet. This groove needs to be deep enough so the cell housing with a 1 ¾ hole will pass over the wire in the groove when side onto the barrel. This will make since when I upload the assembly procedure pictures. I position this groove a half inch from one eng of the barrel. To do this I scribe a line onto the barrel ½ inch from the end I chose and center the groove at this line and widen both sides until it is 3/16 wide to the proper depth.
I know all this is probably confusing and overwhelming at this point but please bare with me and all the pictures I upload will clear it up. My wife will be home Sunday and I will start putting pictures up as soon as I can.
This has been longwinded so I will stop here. Over the weekend I will post more about turning the end pieces and then you will know all I know about Kaleidoscopes by next weekend.
I know you have questions and to help anyone with that I set up a email account for questions and comments. Please feel free to email me and I will try to answer them here so other people can benefit. Suggestions are welcome and your email will not be used to spam you.
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