GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Topic started by: customcutter on June 30, 2022, 04:07:49 PM
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I started on the mount this morning. I finally decided to use a piece of 1X2X4" Al that I had instead of some 3" rod. The first thing I did was cut into 2 1X2X2" blocks. Then I cut them diagonally from corner to corner. I need to make ears on either side so that the two halves can be clamped together around the prismatic cube that splits the image 30%/70% with 30% going to the shooters eye and 70% going to the camera for better clarity. It will also clamp onto the eyepiece of the scope at the same time. I'll have to make one for each scope that I want to mount the camera on.
The prismatic cube and camera are linked in this topic thread "Scope Cam Questions". https://www.gatewaytoairguns.org/GTA/index.php?topic=197390.20 (https://www.gatewaytoairguns.org/GTA/index.php?topic=197390.20)
I was trying figure out how to hold the 2"square for cutting it diagonally and when I pulled the horizontal bandsaw out there was a small C clamp laying on it. It worked perfectly for the job.
The picture of the plastic clamp is what I want to incorporate without the picatinny rail section.
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Next I marked a diagonal with a Sharpie across the opposite corners. Where they would intersect needed to be the center when I chucked the 2 pieces in the 4 jaw on the lathe. I mounted each piece in the milling machine and faced off .010" across the diagonals for a smooth surface instead of the bandsaw finish. Then chucked it up in the 4 jaw and indicated in as best I could, then center drilled it. Drilled it 1/4", 3/8", 1/2", and finally 7/8".
Then I bored it to 1.300" and let it cool. The actual finish size is slightly over 1.3" so I'll finish boring to size tomorrow. By then it was way over 90* in the garage and I had already had to stop twice for water breaks. If I hadn't had the high volume fan going I would have had to stop a couple hours earlier. :o Done for today. ;D
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I was trying figure a way to clamp the 2 pieces together so that I could drill, tap, and clearance drill the 2 halves in the milling machine. I thought that clamping them together before boring would be easier and possibly more accurate. I finally decide that I would bore them first and do the other machining after boring. I think I can indicate off of the bored section and accurately drill and clearance drill the ears on the clamps.
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I think drilling the screw holes would be my first operation. Then bore with a HSS tool bit. Then part with a slitting saw. Tap, drill for clearance, and counterbore whenever you want. You already have pilot holes drilled.
More than one way to skin a cat.
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I think drilling the screw holes would be my first operation. Then bore with a HSS tool bit. Then part with a slitting saw. Tap, drill for clearance, and counterbore whenever you want. You already have pilot holes drilled.
More than one way to skin a cat.
Yeah, if I had thought to drill before I cut the diagonal. That would have been the better set-up. Also didn't think about the slitting saw. Used to use one when making liner lock folders. Not a machinist though, so just getting it done best I can figure. :o Thanks for the suggestions. It'll help with set-ups possibly in the future. ;D
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I decided that the clearance drill would make up for any "slop" and decided not to indicate the holes in the two halves for drilling. :o I put the 2 pieces in the milling vice and "eyeballed" them in square with the top of the vise, I used a center drill to start the holes as the blocks were on a 45* angle to the drill. then drilled them for tapping, then I used a mill to cut pockets for the screw heads. After that I took the top piece to the drill and clearance drilled it. Next I tapped the bottom half with 10x24 tap. I pulled out a set of taps/dies and grabbed the 10x24 just to make sure I had one that would match the allen head screws I had on hand. Then it took me over an hour to find the tap after I drilled/machined the holes and pockets. I swear I've got a Gremlin in the garage, I can't lay anything down and find it a few seconds later.:o I finally grabbed an extendable magnet and started digging around the boxes/containers at the bottom of the mill from when I did the CNC conversion years ago, there it was! ;D
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Here it is after sanding on my 2X72" Burr King belt grinder with 60grit then 100grit. I also hand sanded to a 150grit finish for now. Not sure if I'll take it any farther or not.
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That looks really nice, good job on the DFYI project!
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Looking good Ken! It's coming along nicely.
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Thanks Randy and Paul. I'm tempted to make the housing for the cube/prism out of aluminum as well. Now the focus on the end of the scope is a lot closer. I don't know if it's the 1/2" standoff of the cube or a new focal plane caused by the prism. I'll have to mount a rubber eye piece to stop glare going back to the camera and the one I bought is way too long. Also, there's no way to mount it on the square piece holding the cube. :o
There are other advantages as well including machining the camera mount to the side of the cube housing. Choices, choices... ;D
I almost forgot, I tried the 12mm and 16mm lens's just for giggles. I'm going to have to get the housing more enclosed and permanently mounted before I can decide which one I'm going to use.
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It rained again today, so the shop was a little cooler. I couldn't help myself, didn't like the idea of the plastic housing and thought it was going to be a possible issue with vibration, and like I said before there was no way to put the eye cup onto the plastic housing.
I had a piece of almost 2X2X5" aluminum so I chucked it up in the 4 jaw chuck and turned it down to 1.713"X2.5". Then I drilled it with a 7/8" drill and bored it to 1.000"X 2.5" deep. I used a cut off tool to cut the slot for the clamp to fit. I remembered to chamfer all the sharp edges, and cut it off to 2.5" long.
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Last week I made a little more progress. I milled a flat side on the piece to hold the prism and milled out the pocket for the prism. Apparently I milled the pocket too deep and made a few mistakes on direction with the Y axis when milling. I checked my measurements 3 times at least because I didn't want to make any mistakes on the depth or placement of the pocket and still screwed it up. ;D The only thing I can figure is I don't have any long mills and was using a .190" end mill and had it clamped mostly on the second set of flutes. I think the end mill slipped in the holder and got pulled out slightly. Long story short it wound up leaving small holes on the opposite side of the piece. So yeah, it'll get redone. I might try saving it with some JBWeld, and shimming the prism with some felt on the bottom, but I know it'll drive me nuts if I don't redo it.
When I bought the mill it was halfway between a regular mill and a conversion to CNC with ball screws. I managed to complete the conversion but at present one axis is not functional. So I don't have the CNC or the dials on the X and Y axis to locate from. I tried using dial indicators to get my travel measurements. ;D I need to get busy and find out if it's a stepper motor or one of the break out boards that went bad. :o
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When I milled the pocket for the prism I was trying to figure a way to mill the material that was left in the corners after the mill made the full 1" of travel. I finally decided to use the smallest end mill I had and "drilled" the four corners first with the end mill outside the corners. It had me pulling my few remaining hairs out trying to do the calculations. Adding, subracting, diameters, radius's, etc. Still confused and not looking forward to doing it again. ??? :o
You can see in the pic that the prism cube is recessed about .1000" inch. It was supposed to be flat to the surface. Like I said I think the end mill "pulled" out of the holder, due to the minimal grip.
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I'm trying to see if this will all work, so for now I'm holding off on redoing the buggered piece. Next I started on a tube to mount to the clear camera housing. It will have 4 tapped holes and be screwed to the face of the housing. It will also have to slide into another tube yet to be made that will mount to the piece holding the cube. That way the focal length will be adjustable when I try and fine tune the focusing of the scope, crosshairs, alignment, etc.
I had a short piece of 1.25" Al. I cleaned up the outer edge for a flange, then turned to 1.000", drilled and bored to .800", almost 2" long. I may have to make this larger depending on whether the 12 or 16mm lens has a narrow enough FOV to not pick up the sides.
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I finally finished making the "tramming ring" and got my mill trammed. Took a couple of days but was worth the effort IMO. ;D
Today I squared up the sides and ends of the left over piece of Al that I made the cube holder out of. So it was back to making round parts out of square pieces. I need a mount to go on the side of the cube holder that I can slide the camera mount into that I made in the last post.
Here's this mornings work before it got too hot to be in the garage. :o
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Here it is after drilling and boring to 1.000" for the camera section to slide into.
I still have to drill and tap both ends to mount to the camera case and mount onto the side of the cube holder. I will also mill the square end down to thickness and size to match the flat section on the cube holder. I still have to determine the focal length of the camera. Right now I'm waiting on an extension for the 12 and 16mm lenses. (The lenses focus on the last thread or even slightly longer. :o) Got a notification today from Amazon from Aug 1-11th. :( I'll also have to drill/tap the outer tube so that it can be locked down in place with some allen head bolts. I've drilled the ends of allen bolts before and inserted string trimming line so that they are effectively a nylon bolt and won't mar the metal.
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I did a little more work on the camera case and mount for it today. With the new 12 or 16mm lens it will protrude further out of the camera body and won't fit in the case. I located the center of the lens area and drilled a small pilot hole, then worked up to a 1/2" hole. From there, I moved the case around by hand and used the 1/2" drill bit to ream a larger hole.
I measured the size of the lens window that protrudes from the rest of the case. Tried calculating the location of the appropriate holes, then located the side of the case with an edge finder. I set up the indicators on the X and Y axis, then moved in the correct amount for the first corner hole. I drilled it and moved over to make the second hole on the X axis. I could tell that it didn't look right so I went back and did my calculations again and realized I had forgotten to add the .114" for the radius of the drill. :o I moved over the extra .114" drilled the next hole, then finished the last 2 clearance holes for the 6-32 mounting screws.
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Next I had to drill and tap the holes for the tube to mount to the camera case. I did my calculations again. I put the tube in my small machinist vise making sure the drill bit would clear the vise when it drilled through. I clamped it into the large vise on the mill, I indicated the center of the hole using the edge finder again. I got the holes located, drilled, and finally tapped. I had to grind down the 4 6-32 machine screws that I had as they were about .200" too long.
I still need to mill off quite a bit of the other section, plus mill it down to size to mount on the cube section. It's finally starting to look like it might work. ;D
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Looking good Ken! If nothing else, that thing is going to be bullet proof! I am eagerly awaiting your first video of you taking a rat!
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Looking good Ken! If nothing else, that thing is going to be bullet proof! I am eagerly awaiting your first video of you taking a rat!
Thanks Paul. The lens extenders are on order. Right now the lens is almost in focus on the very last thread. They won't be here until August 1-11th. :( By then I should have all of the parts finished. Once I determine the final focal distance I'll be able to cut down the length of the tubes.
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More progress this morning. I put the piece that mounts onto the section that holds the cube in my larger machinist vise. I squared it to the vise using a small machinist square. Then I milled the rectangular section down to approx. .200" thick.
Next I had to indicate the center of the 1" hole that is bored into it. I trammed the mill in the Y axis from center location .500" (half the hole diameter), then an additional .250" (half the mill cutter diameter), then .136" more (the distance from the edge of the cube to the edge of the cylindrical part holding the cube). I have said before I am not a machinist. I don't have a DRO yet on my mill, and my CNC portion is not functioning. I have to indicate/locate everything manually using indicators. (Several times I've gotten lost in the math, adding/subtracting radius's, etc..) I milled the top edge, doing climb milling, and going very slowly. I knew that the part was not very secure in the machinist vice.
I went back to center, trammed over to machine the right-hand side. Again, I wanted to use climb milling for a better finish and less burrs. As Joe Pie says on his YT machining channel, "If the chip exceeds the grip, then the part will slip." I had milled maybe .200" and the part jumped in the vise. Luckily nothing was damaged, I just had to go through the aggravation of another setup and indicating everything back in. :o Lesson learned, next time do conventional milling to a few thousandths of size and clean up with a climb milling pass. Especially if you have a minimum grip on the part.
I finished up the other 3 sides without incident. The photo is of only the chips from cutting the last side down to size.
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Here is the part balanced on top of the cube section. The camera housing and it's bracket are inserted into the part. Right now they are hopefully much longer than needed at almost 2" long each. I will machine them shorter once I have determined what the minimum focal length is for the 12mm and 16mm lenses.
I still have to indicate and drill clearance holes for the mounting bolts and indicate, drill, and tap the holes in the cube section. Also once I know the focal length I can drill and tap holes for holding the camera section at the appropriate angle, instead of rotating freely inside the other tube.
Coming together nicely.
Edit: Sorry, it rotated the pics 90* left for some reason.
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I got to spend a little more time in the garage this morning. I was able to clearance drill the holes for mounting the tube to the side of the cube holder. Also I was able to locate and drill the tap holes for that tube into the side of the cube holder. Sorry, I didn't get a pic of drilling the tap holes. Here are some pics of it tapped and mounted on the scope on the "new to me" FX Wildcat I got last week. ;D I wish those lens extenders would get here. I might have to dig out the gears for my lathe for metric threading. :o
I still need to turn it down on the end to mount a rubber eye cup. Also once I get the lens extenders I can shorten the tubes to the desired length. Then I'll have to try spray painting it inside and out to reduce glare.
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The lens extenders came in Wednesday and I started fooling with them trying to get either the 12 or 16mm lens to focus properly on the camera. Nothing worked, the best I could do was get it to act like a macro lens and almost focus, but still too fuzzy to be useful. So I pulled the extender off and tried the 12 and 16mm lenses again. Call me crazy but about 4 turns in they both seemed to focus now. ;D
I was trying to hold the gun, adjust the scope, adjust the camera, and nearly dropped it a couple of times. I knew that I had a swivel head vise that had a suction cup base on it. The question was where was it? Finally the other day while I was in the shop I spotted it on the corner of one of the "buried a foot deep" counter tops.
Tonight, I finally had my 3rd set of hands and was able to hold the scope securely while I attempted to get the reticle in focus. I cut the scope eye cup in half and stretched it over the back of the scope. The picture quality on the camera is much better with it in place. It looked washed out before. The only machining left is to either install an o-ring to hold the camera tube in tension and stop it from turning or most likely I will drill and tap some set screws to keep it from turning.
At present I have the 16mm lens installed. With the present set-up the 12mm lens only partially fills the camera screen, and a lot of black in the rectangle around the circle of the scope lens. With the 16mm lens the entire camera screen is filled with the view of the scope. I'm pretty sure that the 12mm lens will work (fill the screen) if I shorten the tubes and bring the camera closer to the cube.
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Nice work. I’m just following along. Can’t say I understand all the complexities but it’s interesting.
Dave
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Nice work. I’m just following along. Can’t say I understand all the complexities but it’s interesting.
Dave
Thanks Dave! I'm not sure I understand everything either. ;D I've probably watched somewhere between 25-50 videos on different builds, and just scopecam videos trying to figure out how to make one. I just couldn't justify buying one, even though I could. :o I just decided a few weeks back to try building it and take it one day/part at a time as time allowed and see where it lead me.
If you have any questions, please chime in. I wish I understood the valves that I've seen you post. I'm hoping to start a gun build later, when the weather cools off, or maybe get started on some swaging dies. ;D Hopefully both, but for now I'm getting familiar with my machines again.