Through the bore flush system

D

diamond

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Thought I'd share my bore flush project and a little experience about building it. It's coming along pretty nicely.

Made with mostly cheap parts I sourced on amazon, eBay or Craigslist: Used hydraulic pump off an old car lift. Tank found on Amazon. Rotary coupler off eBay with a fitting I made out of a barrel scrap threaded for muzzle brake threads, copper washers seal nicely with no leaks. Pressure relief valve from the hardware store. Very powerful rare earth magnet in aluminum catch tray keeps most chips from getting down the return line. 25u hydraulic filter. Pressure bypass and shut off valve to control flow & prevent air back pressure when clearing. Air valve for clearing chamber to measure before final cut.

I have a couple slow drip connections in the manifold under pressure where I mistakenly used teflon tape. Apparently the tape isn't a good idea with cutting oil. Where I used pipe dope compound no leaks. So I need to take that apart & redo it with the dope.

The rare earth magnet is the most powerful thing I've ever seen. It sucks the chips in from across the pan and does a great job of keeping them out of the return. It'll also bust your knuckles against the chuck if you're not careful! lol It's a little bit of a pain to clean off but not bad. I wear latex gloves to keep from soaking my hands in cutting oil when I do that.

At first I used straight dark cutting oil. That was a bit too viscus to have flow around the reamer bushing. I progressively thinned it with mineral spirits until I liked the flow. It's probably 2:1 now. You can see plenty of flow in the video for flushing the chips.

The bypass valve "sings" a bit with oscillations sometimes. Not sure exactly how to prevent that but a slight tweak in pressure setting or the pressure control valve seems to stop it.
 
The relief valve problem I likely from a bit too light of a spring
 
Great post and very timely. I am setting up a similar device for my lathe as well. I have a couple areas that I would like to ask you about. The first is the rotary union. What is yours rated for as far as RPM? What is the price range for it? I'd guess you are turning somewhere around 50 rpm on the lathe, is that close? Can you describe your pressure relief system? I plan on running mine around 60 psi so not quite as high as yours. I want to cover a few different bbl sizes so I think I will be doing a different muzzle connector than yours. For a spider, I am using a length of plastic turned to fit the interior of my spindle bore and the end where the muzzle goes into is bored in a cone shape thus allowing different sized bbl ODs and at the same time it allows for the transfer of the lube. All of this is untested so I am planning for a tweaking session to get it right. Thanks!
 
Hi Husker. I found the rotary coupler on ebay. This specific one is a "Deublin 55-000-003 Union, 5/8-18 UNF RH Rotor Rotary Valve" You can find these or something like it for around $50 new if you search a bit. That's what I paid.

I'm running around 90 RPM in that video. I use mostly HSS reamers. The coupler is rated to 3500 RPM. Way more than I'd spin it even if I ran carbide. :)

My relief is a cheap pressure valve I got on Amazon: Relief Valve It's rated 25-175 PSI. That's one area my system could probably be improved. I'm not a hydraulics guy and not sure this is the right valve for the job. But it works.

I had the pressure about as high as I go in that video, normally I'm more in the 65-70 psi range. It somewhat depends on the barrel & caliber. I adjust the pressure to get the flow I like. Bigger bores, 5r rifling, etc. I get more flow and use a little less pressure. That was a .22 cal 4-groove and needed a bit more oomph to get the flow I liked.

I do my muzzle threading first, then turn the barrel around and cut the chamber. All the rifles I work on are PRS/NRL style competition rigs so braked and almost all are threaded 5/8x24. All it would take is another coupler threaded for 1/2 or 3/4 if I needed it. This way I don't have to worry about muzzle diameter, If I wasn't working on a braked rifle, I'd have to do a turn the barrel around again for 3rd op to part off the threading and cut a new crown. But even the hunting rifles I work on are threaded.

For me I like the positive seal I get with the threaded muzzle and copper washer and it works for the type of work I do. I'm paranoid about a blow out. I've heard smith buddies tell stories of their shop taking a bath and I get enough all over me as is.

I'm not real sure about your description of your spider set up and how you'll get a seal & not leak profusely under pressure. There are some designs that compression fit with one or more rubber o-rings on the end of the barrel. If I worked on non-threaded barrels a lot I'd make something like that but the variation in muzzle diameters would be a huge pain.

Also not to get critical but it sounds like you're indexing on the outer diameter surface of the muzzle if I understood you correctly. Can you adjust the barrel at both ends to dial in your chamber cut perfectly concentric and parallel to the bore at the point of the bullet meeting the lands? There's lots of discussion elsewhere about dialing in a barrel so I probably shouldn't hijack my own thread there. lol

One more tip I'll share if you do put in a air hose connector so you can blow out the barrel (and I recommend you do) just be careful how much you pressurize the line. That's another good way to take a bath in cutting oil. Ask me how I know. :rolleyes: Also too much air makes oil vapor. I don't like breathing that stuff. I just crack the valve very slowly and wait for the oil to start flowing out into the catch tray. Once it's cleared out I can measure my final cut.

Hope that helps!
 
It indeed helps, thank you Diamond! Your system sounds very close to what I want to do and I am also dealing with other calibers. Eventually I want to emphasize on 50 bmg and ELR calibers. I would have less variation for sure. Yes I am indeed making the sin of indexing on the outside. I have read and studied and watched till I can't watch no more and am convinced that today's bbls, as long as they are reputable, have bores concentric with the OD. (Confirmed by the bbl I have currently) That statement I understand can very much create controversy but I have watched a master machinist/gunsmith produce world championship bbls doing it that way. I have learned enough in my very short time to understand that there literally is a thousand ways to chamber a bbl and whosoever does it a certain way, then that is the only way he knows. I am concerned with my oil system the way I have it as well. I don't think I can get a good seal with my current setup especially with the smaller calibers. That is a thought about threading the muzzle. I could either leave it that way or chop it off when I am done and crown. I will ponder that one. Initially I thought about using a "plug" to go inside the bbl but I can't see how that would allow enough oil to flow through with the smaller calibers. I like your idea of being able to increase pressure on the smaller calibers since that would definitely be a flow issue so I will look into a valve similar to yours. I am the type to work with what I have so there will be many variances I am sure. Thank you so much for the info!
 
A power steering or small hydraulic pump would work great too, with a small motor. Maybe a treadmill motor so you can dial in the flow/psi without having a "majority bypass" through the pressure relief. Just thinking out loud....
 
I used a carbonator pump with Marathon motor from Ebay. Bought some springs from local hardware store that fit internal relief and cutting them down until internal relief on pump was by-passing at 60 psig. I used 2 gals Ridgid stainless cutting oil mixed with 4 quarts of type F automatic transmission fluid. I used a Greg Tannel BTS adaptor which is a swivel connection with a spring loaded rubber tipped nozzle. You don't need a threaded muzzle to use. It secures to barrel with nylon screws and works pretty well at least up to 300 RPM. When you order reamers, you can specify your using a thru barrel coolant system and they'll modify the end for coolant flow. You can file notches in your bushing screw retainer too, not as good as reamer manufacturer but it helps.

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nice write up, thanx. Some days I get tired of the cut a little clean a little and repeat and build a flushing system. I like the power steering pump idea. I use the remote reservoir pumps from KRC for the engines we build. They have an adjustable prv built into the pump. I like the universal muzzle adapter idea but dang that product seems a bit spendy. Is there something exotic in the internals? As to the fella that indicates on the od, I have never, ever, heard of any reputable smith use that technique. A little study of the process of gun drilling followed by some practice finding the direction of the crown of the bore oughta turn anyone away from that technique pretty quick.
 
It was cheaper when I bought it. Patents are expensive. You extend the life of a $300 reamer another 15 barrels and it's pretty cheap. The barrel flush makes it where you can chamber in 15 minutes or less. I'm turning reamer at 200 rpm.
 
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