jid2 Posted April 28, 2012 Share Posted April 28, 2012 When drilling holes in a barrel to add porting is there any magic to deburring the inside? It seems like a difficult task given the rifling. Perhaps the key is using a nice new sharp drill bit and cutting fluid so you avoid the punch through burr all together? Link to comment Share on other sites More sharing options...
edgardo Posted April 28, 2012 Share Posted April 28, 2012 Electroerosion,es la forma de ralizarlo Link to comment Share on other sites More sharing options...
jid2 Posted April 28, 2012 Author Share Posted April 28, 2012 I dont think EDM machines are what the typical gunsmith is using. Link to comment Share on other sites More sharing options...
Toolguy Posted April 28, 2012 Share Posted April 28, 2012 I do mine on the mill and use a 2 flute ball nose end mill. It works best to drill a pilot hole about half the size of the finished hole. For example, a 1/16 drill, then a 1/8 ball end mill. With the ball end mill, any burrs are very small and thin and can be knocked off with a bore brush. Be sure to feed the end mill slowly instead of punching it through. Don't try that on a drill press or with a mill setup where the barrel isn't held solid. The spindle and barrel have to be pretty rigid. If not, the endmill will just make a ragged chewed up hole. Link to comment Share on other sites More sharing options...
kmca Posted April 28, 2012 Share Posted April 28, 2012 Might not be what the typical gunsmith uses, but the shops like ProPort, Briley, Magnaport all use EDM. Link to comment Share on other sites More sharing options...
jid2 Posted April 28, 2012 Author Share Posted April 28, 2012 Im looking for tips that will help me, in my garage with a mill add some holes. I understand EDM is the production method. Ball mill seems like a nice trick. Perhaps putting the barrel in the slide with it locked in place will help make the holes vertical, although it can be aligned out of the slide as well. Link to comment Share on other sites More sharing options...
open17 Posted April 28, 2012 Share Posted April 28, 2012 Fill the barrel with cerrosafe. Center drill/drill slightly undersized/finish with a endmill. "peck" the hole through, plenty of lube. I like Mystic Metal Mover, but WD-40 works OK. Warm it up, pour out the cerrosafe---no burr. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted April 28, 2012 Share Posted April 28, 2012 Hello: You can also use a lead bullet and push it into the barrel where you want to drill the holes. After you are done push the bullet out. Or you could just shoot it alot to remove the burrs Sharp cutters are your friend Thanks, Eric Link to comment Share on other sites More sharing options...
jid2 Posted April 28, 2012 Author Share Posted April 28, 2012 Good ideas, keep them coming. Link to comment Share on other sites More sharing options...
jid2 Posted January 3, 2013 Author Share Posted January 3, 2013 Update. I put two 3/16" holes in my barrel. The overall outcome was good, the in between got a touch dodgey. First I milled a slot in my slide. Since my slide used to have a front sight, and I already have a slot in it further back things are a little busy up there - but the new slot cam out nice. Then I setup the barrel in the vise indicated it to get it straight and centered and got started. I first center drilled. Then I came in with a HSS .172" drill bit spinning at 1100 RPM and plunging at 1.3 IPM with a peck drilling cycle and some cutting fluid. Things were going smooth.... until the tip broke through the ID of the barrel, then it started to grab, stopping the drill bit in the chuck and making horrible sounds. So I killed the machine, retracted, and tried again at a slower plunge rate. Same result but with a broken drill bit. 2nd hole went about the same, but I stopped trying before I broke a 2nd bit. I then came in with the 3/16" ball endmill to finish the holes, ran it at 3000 RPM and plunged at 4 IPM - that went smooth and left the inside looking good. I then took some passes with a copper cleaning brush and called it good. We'll see how it shoots this weekend. Any ideas for the break through issue. My thought is to use a more rigid carbide drill bit. I'm afraid to slow the plunge down too much and reduce the chip load to the point where I'm just work hardening the material. I assume that the work hardened surface of the inner barrel is what is causing the problems along with the fact that stainless is a beast at break-through in general. Here are some pics and a little mahining video of the slide. I consider all this practice on my existing gun before I start building my new one. Link to comment Share on other sites More sharing options...
Toolguy Posted January 3, 2013 Share Posted January 3, 2013 First off, you are running too fast of RPM and work hardening the metal. Secondly, on the drill the twist is a problem because you are coming out into a curved surface where the drill breaks through one part before another. To fix this use a straight flute solid carbide drill running about 750 RPM with a z feed of 3 IPM. Then do the ball end mill at 3 IPM and 1000 RPM. Your tools will thank you. Link to comment Share on other sites More sharing options...
Flexmoney Posted January 3, 2013 Share Posted January 3, 2013 A lead slug (bullet) in the barrel as a backer? http://www.blindhogg.com/gunsmith/porting.html Link to comment Share on other sites More sharing options...
jid2 Posted January 3, 2013 Author Share Posted January 3, 2013 First off, you are running too fast of RPM and work hardening the metal. Secondly, on the drill the twist is a problem because you are coming out into a curved surface where the drill breaks through one part before another. To fix this use a straight flute solid carbide drill running about 750 RPM with a z feed of 3 IPM. Then do the ball end mill at 3 IPM and 1000 RPM. Your tools will thank you. Thanks for the input. Moving to a straight flute solid carbide drill was going to be my next step - so it's good to know I was on the right track. So even with a solid carbide drill (say 1/8") I should run the RPM at 750? My speeds and feeds calculator said I should run it at 5300 RPM and plunge at 10.5 IPM. But I don't take that as gospel, and will likely use your recommendations. I know I was pretty happy with how well that 1/8" 2 flute carbide endmill cut the slot in the slide. That was at 5700 RPM, with .15 DOC and 0.018" stepover at 10 IPM. Again thanks for the input. Link to comment Share on other sites More sharing options...
AlexOsensei Posted January 11, 2013 Share Posted January 11, 2013 what kind of hardware are u using? Link to comment Share on other sites More sharing options...
kneelingatlas Posted January 11, 2013 Share Posted January 11, 2013 That's fantastic work; you make me look like a caveman! Link to comment Share on other sites More sharing options...
jid2 Posted May 8, 2013 Author Share Posted May 8, 2013 Just an update to this thread for those searching through things. On my recent gun I used a 1/8th inch solid carbide, straight 2 flute drill and ran it at 3050 RPM (100 SFM) and 3.2 IPM plunge. It cut fantastic, then finished with a 3/16" ball end mill. It think I could have just went with a 3/16" straight flute carbide drill and called it a day. Link to comment Share on other sites More sharing options...
Toolguy Posted May 9, 2013 Share Posted May 9, 2013 Good job! Link to comment Share on other sites More sharing options...
Croomrider Posted May 9, 2013 Share Posted May 9, 2013 I'm glad you found a solution. However, the only reason you were having a problem in the beginning was a lack of rigidity on your equipment. A twist drill will not break when entering a barrel unless is is allowed to grab and pull it's self in when the point breaks through. With rigid equipment and ball lead screws, this will not happen unless the tool holder it's self is not holding the drill tight enough. Mike Link to comment Share on other sites More sharing options...
CAB33 Posted May 9, 2013 Share Posted May 9, 2013 EDM is not possible for this task. Cut a land, spot drill, drill .01 under, then 2 flute end mill will give you a straight hole, on location with no burrs and clean sides. Link to comment Share on other sites More sharing options...
38superfan Posted May 9, 2013 Share Posted May 9, 2013 I'm glad it worked out for you. Starting a collection of trashed slides and barrels to monkey with for this purpose. Thanks for sharing! Link to comment Share on other sites More sharing options...
Croomrider Posted May 9, 2013 Share Posted May 9, 2013 EDM is not possible for this task. Sure it is. Are you thinking only of WIRE EDM? Mike Link to comment Share on other sites More sharing options...
jid2 Posted May 9, 2013 Author Share Posted May 9, 2013 Yes sinker EDM would work, but not in my garage as stated in the earlier. My twist drill setup did have the problem of the drill slipping in the standard drill chuck, so this was likely a problem. My machine does have balllscrews with pre-loaded double nuts, and only about .0005" backlash. Using an ER20 collet for the carbide drill was a step in the right direction for sure. Link to comment Share on other sites More sharing options...
38superfan Posted May 10, 2013 Share Posted May 10, 2013 Any concern of that web in between cuts cracking. Link to comment Share on other sites More sharing options...
1ltrng3bn Posted June 7, 2013 Share Posted June 7, 2013 you should steer clear of using hss for anything! use at least cobalt.. better yet, drill with hi-roc-acts just like a reamer. Link to comment Share on other sites More sharing options...
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