GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Show Off Your Air Guns With Mods (SHOW and TELL) => Topic started by: Finn on July 05, 2017, 07:21:49 PM
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I've been working on building a multi purpose target gun mainly for training 3 position and 10 meter shooting. I started designing the prototype somewhere around march 2017. I wanted to test many ideas, and from the beginning it was somewhat clear that this should be primarily a precision paper puncher, not a power tool.
Early April I had the first sketches of the gun and I started working in the garage. First thing to make was the basic frame. In principle its a simple piece of aluminium, but there is so many places to screw it up. First night in garage I managed to drill two holes, so not very much. Second night in I machined five threads and that was all I had time to do in three hours. Threading with CNC lathe is fairly trivial task but making sure the part is absolutely straight and centered takes time.
Next weekend I had time to do some milling, last two photos show the trigger group slot milled and pin holes are also drilled. In the last picture you can see the brass regulator housing.
I noticed its 1:30 am already and my dayjob starts at 7am so maybe I post some more info and photos tomorrow.
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Very cool 8)
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Must be, its desingned in sub zero climate conditions. ;D
Here are some pictures of the design, its pretty conventional PCP target gun action.
In the first picture the action is in resting state after firing. Trigger functions are set with M3 grub screws, foremost screw adjusts second stage pull weight, second one is sear engagement, third screw is first stage travel, fourth screw just behind trigger blade is overtravel adjustor and final screw behind the trigger is first stage pull weight.
Trigger has small instrument ball bearings for smooth and reliable function when pull weight is set to minimum value (close to 20 grams or 0,7 ounces). Yellow part is brass regulator housing and above that can be seen five belleville springs and aluminium piston. Regulator is set by M5 grub screw from below. Stock will be attached between the frame an UIT rail and to the rear mounting block with 3 M5 screws.
That lever above the hammer is for dry firing mode, detent spring is hidden in these pictures. Cocking levers are pretty self explanatory, small external lever above the trigger is sear reset lever. Most designs have resetting built into the hammer itself but i couldn't fit it into the available length thus the external setup. Sear would work without resetting when 2nd stage pullweight is fairly light, but heavier setting locks the sear down after firing.
I have made these parts already but don't yet have any properly good photos of them. Material is CrNiMoV4 and contact surfaces are hardfaced with stellite 6 superalloy since it seems to have lower friction and it resists corrosion and wear.
I will post another update as soon as I have good pics to show.
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pretty conventional , I think I saw a worm gear in there ;D
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I think you have mistaken the splineshaft for worm gear. Splines are there to give possibility of changing the cocking lever from right to left and index it in 10 different positions (to clear the scope rings for example).
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very cool, excellent planning, ill be following the thread for sure !
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You guys that know machining impress me.
...when this baby hits 88mph...
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Couple more design pics. Frame sits inside carbon fiber stock, and furniture is attached to aluminium rails. Grip is rail mounted and has balljoint to allow for adjustment in any direction. Front stock moves back and forth, I also want vertical adjustment and horizoltal tilt but I have no idea so far how to make it fit (any good ideas anyone?). Barrel is 16mm choked LW .177, it's hidden inside the aluminium shroud. Steel muzzle piece is threaded on the barrel and in turn stretces it against he shroud for added rigidity. Normal rail mounted globe sight with inserts, air cylinder is hydraulic pipe and uses hatsan type fill probe.
Rearview shows adjustable aluminium buttplate and cheekrest. Cheekrest can be moved in any direction and it tilts in two directions. Buttplate has length of pull, height, rotation and tilt adjustments. Buttplate curvature can be also be adjusted.
Rear sight and cocking lever are missing from the pictures, I haven't had time to design the rearsight yet, maybe this weekend.
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Heres a few stock parts, most of em completely unfinished but still look something like the design.
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everything looks incredible..
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Thank you.
I'm always too busy while making something, never enough time to take a few good photos, I did however take a few bad quality phone camera photos of the stock making process.
First pic shows some of the plywood plug parts, small hobby bandsaw was really handy tool for this.
In the second pic, all the parts are together and mold fence is glued on with hot snot, after that the whole thing was carefully sealed and waxed.
Next thing was to laminate fiberglass on the plug. When it was cured, I removed the fence (pic 3), waxed the fence surface and laminated the other side. Once fully cured, I trimmed the perimeter and separated the two halves. After couple of hours of cleaning an waxing the mold was ready for use. I used combination of different carbon and glass fabrics to laminate the stock itself, I did this one half at a time and used a vacuum bag to hold the laminate in place while curing.
Once the parts were partially cured, I removed the mold from vacuum and trimmed the excess with box cutter blade. Then I bolted the two halves back together and laminated narrow strips of carbon to all the seams.
It really was quite a circus to laminate the parts together from few narrow openings with a long stick with gloves all sticky from the resin and full of long gluey carbon strings, but it turned out just fine in the end.
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wow, lots of work.. nice job on the vacuum seetup
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Not so productive day today. I did some quick backyard testing however and measured a velocity of few shots. I had somewhere around 140 bar in the gun and set the target at 10 meters (33 feet).
First shot went way low and second one just under that, so I adjusted the sights. Now it was on target but sounded really weak, I decided to measure the velocity and it was just touching 280 fps. Something wasn't feeling right and I pondered if the dry fire mechanism was jamming the hammer and causing low velocities and went on to remove that part to test the theory.
It turned out to be the hardest ever part to remove because there was some garbage jammed between the frame and the small plunger and it wouldn't just freely fall out. However I finally got the part out and tested the velocity and it was pretty much the same, I was sure that there was something going on with the regulator although I had adjusted it correctly. Turned the regulator setscrew and it was all loosey goosey when there should be considerable resistance in pressurized gun. Turned the setscrew where it just touches + half a turn and tested the speed again. This time it was definitely better 492 fps but still lacking, so another quarter turn tighter and it goes up to 660 fps. I wanted to have some velocity strings, but chrono said: nope its too dark, please try again another day.
I managed to shoot 25 shots at paper targets, three targets have five shots each shot standing from 10 meters and the last target has 10 shots from 30 meters. I didn't have any bench available so I shot the 30 meter target from knee position.
It seems like an easy gun to shoot but the regulator thing has to be investigated, maybe one of the springs is broken or the screw needs to be locktited.
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holy cow, is that the completed gun in the pic?
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It is not absolutely complete but it works, many parts are to be made and so far only few pieces have been anodized. All the alu colored parts need polishing and anodizing. Stock and grips also need much thicker clearcoat so it can be properly polished.
Rear sight parts have to designed and machined etc. and front stock adjustments need thinking, recoil absorber is also WIP,
Hard time deciding what colors to use for all the alu parts, opinions anyone?
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Gorgeous. I'd go with blue for the aluminum parts.
JMJ
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same , 2nd vote for blue
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Wow...you have some serious talent, Sir!
From planning, to making chips, to final assembly...beautifully executed all around! 8)
Vote #3 for blue anodizing...would tie in nicely with your grips ;)
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Ok heres a few renderings of those color schemes, I got the grip color looking almost right. I think it would be a bit boring if all the alu parts are dyed blue. I had this idea of adding gold or magenta colored highlights. Let me know what you think or if you have an artist inside you, suggest something. I really want to get it right the first time, I'm absolutely sure that if I don't, I'll probably stick with the ugliness rather than machine a bunch of new parts. :D
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Red, grey, and maybe a little gold somewhere for an accent.
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Wow! Amazing work.
I vote for blue.
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Had some range time today. As usual I looked outside and weather was superb, but the minute I arrived at the range it started to rain and wind picked up.
Only shot two paper targets, after couple of minutes into shooting rain was getting too heavy for those so I switched to steel plates. I only had four 40 mm dia. steel plates to shoot, so lots of running back and forth in the rain. Plates went down with ease, and the two 5 shot groups I managed to shoot were 33mm (1.3in) and 27mm (1.064in). I used 8.2 grn. RWS meisterkugeln and range was 40 meters (43.7yds), sandbag rest and diopter sight. What I really need now is better weather and better long range pellets to really test if the gun needs to be modified somehow. I'm guessing H&N FTs or the usual JSB exacts will improve things.
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Lets continue the story, I've had good and bad luck. Sunday evening I started machining rear sight parts and everything was going well and just when I least expected the worst thing happened, and my trusty mini mill decided it was time to shred the plastic primary gear into million pieces.
I was furious, mainly because I had forgotten to take out the spindle locking bar before twisting the volume knob, and therefore had no one to blame.
Today I called the place where I bought the mill and sure enough the guy said that the gears are not stock item but available from manufacturer. Funny how I didn't ask what the exact price was. Anyway I was sure that it can't be very expensive and he ordered it for me. Later he called me again for shipping details and then it popped in my mind "ask the price", and when he told me it was going to be somewhere around 80 euros I almost choked.
I told him that it was a robbery at best and order was cancelled, the lucky part was that while surfing interwebz for o rings, I found a place where same size machined steel gear was 17 euros so thats what I'm waiting now to arrive.
I also did some pellet testing and had no luck with crosman products. Has anyone had good experiences with 7 grain crosman domed or crosman destroyer pellets in .177, like less than inch 5 shot groups from 45 yds?
I was surprised to see that RWS wadcutters did a better job than domed pellets at longer ranges, I guess it comes down to quality control.
Destroyers were apalling, even from 10 meters away there was no grouping, might be even worse without choke.
JSB Exacts arrived today but it's pouring rain so no testing.
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same mill arrangement I have , but the gears are readily available in the US for 5-20 dollars , depending which one and whether you need steel or plastic.. Bummer.Glad you eventually found one .. I haven't thrashed the gears on mine yet, but one day I'm sure I will.
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Surely that gear was doomed from the day it was made, pom gears are not good enough for machine tools, on the other hand it acted as a fuse and might have saved the main gearbox from destruction. I still doubt that the small motor would have enough torque to break steel gears even without fuse parts.
I'm going to convert it to belt drive soon, but first it needs to be in running condition so I can make the required parts (or set of gears). I hope that the other gears are in good enough condition to mill the parts for belt mod. I'm also making a new hydro test equipment, I'll need that before the ebay compressor arrives.
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MAKES sense .. its like when I'm making something for my lathe , forget I need the dam lathe to make it , and already have the lathe half apart lol
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Finally the gear has arrived, it's sturdy enough that I can slice it with a hacksaw and have two gears for the price of one. It doesn't have a keyway that was shown in the product picture, but thats easily done in a lathe.
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Got the mill working again and I must say that steel gears make some proper noise. Also had time to make a new tube endpiece with pressure gauge. Range testing revealed nothing new, best five shot groups were 23 mm from 50 meters with diopter sights, JSB exact 4.52 works well with this gun.
The velocity has to be in certain range between 195-200 m/s or the accuracy starts to suffer. What might be causing this? I have the regulator set close to 85 bar and indeed there is noticeable muzzle flip (recoil absorber mass removed), but it gets stronger below 85 bars. I think I need lighter hammer, it's 18,5 grams now.
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Ok now I'm officially impressed!
That is one sweet looking rifle.
I'm usually in too much hurry to make something pretty, and sometimes I can make something half pretty.
Dryfire system and all, like the big name competition guns, nice.
Marko
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Incredible, seriously incredible. Main color Blue with red and gold highlights.
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Thanks for everyone, this has not been the easiest project but hopefully I can finish this sooner or later.
I've been busy making other parts for compressor and today I bought my first scuba tank and need some parts for it as well. Tank will help a lot when testing shot strings and power settings, requires a lot of shooting.
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My fill station project is finished, it has only basic functions but so far it has worked very well. Blue knob is bleed valve and red knob adjusts the fill speed.
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very nicely done !
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You have mad skills. Amazing.
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I see by the posts several of you members live in Finland (Suomi). If you feel like it, please PM me your specific locations. Having lived there for 8 years, there might be some useful info to share. Thanks.
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im am truly impressed with your talent. that is a fantastic rifle!
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Anodizing has begun, shroud is in the acid tank, I'm nervous and anxious to see how it turns out. I have only one long and narrow container so it has to be used for cleaning and dyeing and washed carefully between each step. It's now 20 minutes to disaster or success, and it is time to heat the dye and make a mess of my kitchen.
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I have a solution for you, very cheap. Parvekelaatikot! And for you english people, long balcony flower box in plastic. ;)
Marko
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Those could be useful although I don't think you could boil parts in them. This time I wanted really electric blue so I used salvaged HP printer ink and I only have half a liter of it so the boiling pot had to be the exact size. Maybe I'll do as many parts as possible tonight, it is going to be a long night for sure. I try to post some pictures of progress when parts are in electrolysis.
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I use them as electrolysis tank and for dye, the dye only needs 45-55c and those boxes can take that easy.
Gaterosplating dyes work nice and are not too expensive.
Marko
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Yes I have bought stuff from gateros and they work well especially that deep black dye, if anyone here wants to try anodizing something I recommend searching for Sanodal aluminium dye. I prefer the HP printer ink in some situations, it easily produces very even and bright color and does not leave any residue, of course it is pia to dig it out of the cartridges but it will last a long time.
Couple of pics, last two photos show what kind of current densities I usually have, theres five small parts 13.4 volts 2.50 amps. Sulfuric acid is close to 10% and temperature is around 20c. DIY power supply has thermal cutoff that kicks in at 30 minutes so I keep the back door open to cool it. I have a strange obsession with led displays, I would have them on my gun if it was necessary.
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What kind of mix do you use with the inkjet dye? Or straight ink and thats it?
I have done some anodizing also but mainly use gateros dyes.
Marko
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I'm not absolutely sure about the mixture, I went to a local computer store and asked for used printer cartridges and after some explaining got something like 30 of those, at first they were suspicious that I would start refilling business.
I whacked the lids off with hammer and separated the ink sponges into three buckets. Then I added a liter of water to each bucket and squeezed the ink out of the sponges. At the end I had cyan, magenta and yellow maybe 0.7 to 1 liter of each. Inks look opaque in 0.5 liter plastic bottles, except for the yellow which appears dark orange. Two minutes in warm ink gives parts very dark color.
BTW just had the craziest idea to try if dark coffee works as a dye.
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Ok, thanks. Btw, coffee wont work, i has grease in it.
Dont ask how I know ;D
Marko
Nice looking parts by the way.
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everything looks great!
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S**t, I may have ruined a batch of parts. Acid tank is outdoors under a plywood box and I forgot to put the lid on it and just after few minutes the most powerful rainstorm started and water was flowing everywhere, power supply and acid tank included. I didn't stop the process as current was still flowing, hopefully it turns out good.
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Luckily those parts are fine, few more batches to go. I've been up all night polishing parts with worn out patches of sandpaper, my fingers start falling off any time now.
Batch two: cheekrest horizontal adjusting piece and pistol grip balljoint parts.
Batch three:bolt, valve spring retainer/chamber, hammer spring adjuster, frame rear mount and front furniture t-nuts.
Batch four: UIT front rail, pistol grip rail, cheekrest knobs and stock rear plate.
Time for breakfast an coffee.
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This thing has too many parts, I bet your gun doesn't have RC helicopter ball bearings, this one does.
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that's one seriously complex breech assembly, the trigger pack looks awesome
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That is some nice engineering indeed. Rc helicopter bearings, cool. Did you strip a helo for this or had spares?
Marko
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Finn you're doing a beautiful job on that gun for sure.
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Took couple of photos outdoors, blue color is so bright it almost looks like CGI. I should have cleaned the gun first, it has a lot of fingerprints and dust.
Marko, I had box full of align Trex spare parts, helo still flies.
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Holly cow that is pretty, (ihan helvetin hieno!)
Another copter flying and airgun making Fin, I have also couple of birds, 250-500 and 600 trex. Later one is turbocharged.. But I think you knew that.
Marko
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Looks really cool Finn. That is a piece of art.
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Thats looking very nice! very good job.
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One of the nicest things about diy guns is that you have all the factory test equipment. Here I'm setting the regulator pressure, very easy when it is externally adjustable and you can shoot the gun while adjusting.
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Added front grip risers and translucent eye cover and scored a couple more points in 10 meter air rifle match.
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Beautiful. Some serious machining skills displayed
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I almost never ever post here due to some previous issues but I still drop in occasionally and this absolutely required a comment. Well done all the way around. Fantastic job of machining.
Pat
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Beautiful and extremely functional, a credit to your skills sir.
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Thanks for the encouraging comments. I have made some improvements and modifications to the rifle.
-New front sight tunnel with glass inserts
-Ground a set of front sight magnifier lenses
-Designed and built a custom rear diopter sight
-Longer barrel extension with integral silencer
-Paintwork in progress
-Recoil absorber system is now complete
-Balance weights added
-Fore stock height adjusters
-Increased plenum volume and stiffer valve return spring
Pictures show the operation principle of the air operated recoil absorbing mechanism and associated parts, system has two adjusting screws and can be matched to any common pellet weight.
Rear sight and shroud + couple of misc parts are currently unfinished aluminium but all those bare parts will be anodized in the near future.
Rear sight tube has threads to accept filters, polarizers and whatnot, one click turned out to be 0.1 MOA.
I have shot over 5000 pellets through the gun and so far the only real problems have been one blown regulator o-ring and the trigger had to be cleaned from carbon fiber dust because the gun would not fire. I recently washed the inside of the stock to clean off any dust.
I think black is the color for those new parts.