UTArms80illetLowerCompletiononaDrillPre…….

1、UT Arms 80% Billet Lower Completion on a Drill PressThis tutorial will cover the process used to complete a UT Arms 80% lower using only a drill press and thefixtures from UT Arms. A drill press is desig ned to drill vertically, n ot mill horiz on tally. Due to this fact, extracare must be taken. Be

2、 sure your chuck is secure and check it often. It has the tendency to come off if you puttoo much side load on it. This can cause serious in juries. This tutorial is forTools Required:-Drill Press-Alle n Wren ches-1/8”Drill Bit-3/8”Drill Bit-7/16”Drill Bit-?”Drill Bit-Drill Stops-3/8”Endmill-Caliper

3、s- Fixture and Receiver From UT ArmsNew drill bits are recommended, but not required. Many of the drilling operations involved are tedious andthe drill bit will try to walk out of position. New, good quality drill bits will help mi ni mize, but not elimi nate thiswalk ing effect.st1 Operation: Mount

4、 Receiver in Fixture.The fixtures from UT Arms make this simple. Simply align the side plates on each side so that the pins align withthe front and read take down pin holes. Squeeze them together, and then place the supplied bolt through themagazine release hole. Thread the bolt into the other side

5、and tighten with an alle n wren ch.Mount the top plate with 36 small holes in it to the side plates using the 4 supplied hex cap screws. Make sure theplate is flush with both of the side plates and tighte n.2ndOperation: Spot Drill (36) 1/8 ” HolesUsing a 1/8” drill bpot drill each of the (36) holes

6、. Just drill down about 1/16” into the receiver.After all holes are spot drilled, remove the top plate and finish drilling the holes to a depth of 1.245By rem oving the top plate, you are sav ing wear on the holes in the fixture and your fixture will lastThe easiest way I have found to get this dept

7、h is using a drill stop. Place the stop at the correct depth on your drillbit so you will know whe n to stop drilli ng. Just check it occasi on ally to make sure it hasn t moved.Go slow when drilling these holes and remove the chips from the drill bit often to prevent walking and possiblybreaking th

8、e bit. Using a lubricant will make drilling these holes esasier. These holes are time consuming, but ifyou rush you could damage your receiver or break a drill bit off in one of the holes.3 Operation: Drill (14) 3/8”HolesThis is the most vital and most difficult step of the process. It can be diffic

9、ult to keep the 3/8from walking off course. Just take your time and be extra careful. You will be pretty good at it by the time you finish.Switch to a 3/8”drill bit and drill th14) holes indicated on the template to 1.245”. These holes cabe hard to drill because after the first one, the holes begi n

10、 to overlap. I have found itfirst row, and then drill every other row, and then come back to the ones you skipped. They are still tricky, but thisleaves the same amount of material on each side for the bit to cut. The drill bit will try to walk. Keep a really firmgrip on the fixture and go really sl

11、ow. This process will remove most of the material in the fire con trol pocket.Here you can see how I skip a row and the small porti on of material left betwee n. Whe n you go back to drill theskipped rows, go slow and try to keep the drill bit from walking, especially towards the outside of the rece

12、iver. If itwalks towards the center of the receiver you can clean it up with the endmill, but it walks toward the_outside, it willleave a groove.4thOperation: Drill (1) 7/16”Holedrill bit and drill the 1 hole indicated on the template to 1.245Now you should have a rough fire control pocket that look

13、s something like this. If you look close, you can see thebits of material left on the sides by the drill bits. The next step will clean most of this up. I took this picture before Idrilled the 7/16youcartnglel; thet idea.th5 Operation: Mill the Front Portion of the Fire Control PocketAttach the plat

14、e to the top of the fixture that has (6)1/8 ” holes in it. Be sure it is centered as before.Put a 3/8”endmill in the chuck and make sure it is as tight as you can get it. The drill preo idesigned for side loading, and the endmill will have a tendency to slowly work its way out. Check it ofte n.I use

15、 a 3/8”endmill with a cutter length of 3/8”from MSC Direct. Cutter length is the length thcutters come up the side of the endmill. Long cutters make it difficult to mill the pocket without damaging the fixture.Just make sure the endmill you choose is center cutting.For the first pass you will have t

16、o go really slow as you will be milling deeper to avoid damaging the fixture. Adjustthe drill press table so that the smooth sha nk of the en dmill isat least ?”below the topsurface of the milling plate. Failure to do this will damage the fixture.Lock dow n every adjustme nt your drill press has. Mi

17、ne has a lock ing screw on the table height adjustme nt andon the colu mn where the head swivels left and right. You want everyth ing to be still and stable. Its best to leavethe chuckthe way up and use the table to adjust your depth. Just be sure to lock it back down each time.Use plenty of cutting

18、 fluid during this entire process and keep the chips cleaned out using a shop vac or othermeans.Keep a tight hold on the fixture and mill in a clockwise directi on using the milli ng plate as a guide. The smoothshank of the endmill should ride against the milling plate. The first pass will vibrate a

19、good bit as you take a pretty deep cut. Slow and steady is the key. This pass is the most difficult and the most likelyfor somethi ng to go wrong. Stop a few times and make sure your chuck is secure and the en dmill is still tight. Alsomake sure you are deep eno ugh and the en dmill is not cutt ing

20、into your milli ng plate.Switch to a 7/16After the first pass, drop dow n about .025” (25 thousa ndths of an in ch) and make ano ther clockwisepass. This one should go much easier. Be sure to keep your chips clea n and the cutter lubricated.Continue to mill going down .025”with each pass and go in a

21、diloctwisentil you reach adepth of 1.25”. Depending on the length of your endmill, you may have to remove the millingaateyou get near to full depth Just make sure that at least ?”of the smooth shank on the endmill is belothe top of the receiver. Use the area on the receiver that you have already mil

22、led as a guide just as you used themilli ng plate as a guide before.Be sure to lock dow n all adjustme nt poi nts on your drill press each time.The last little bit of depth is a little deeper than the holes you drilled. This will get rid of the dimples left in the bottomby the drill bits. This is wh

23、ere a center cutting end mill is important.Be sure to check your chuck and en dmill ofte n to make sure no thi ng is coming loose. Using the drill stop isoptional here, but I would recommend using it because the endmill will want to work its way out of the chuck. Thiscan cause you to go deeper tha n

24、 you wan ted without knowing. If you don it, stop ofte n and check your depth.Check you depthfter every pass whe n you get close to 1.25Don t worry too much if the sides of your fire con trol pocket are not perfect. You can sand them smooth with a fileor dremel after you are fini shed.After the mill

25、ing, I had some grooves left in the side of the fire control pocket where the drill bit walked off a little.This can be smoothed out with a dremel when everything else is done.th6 Operation: Drill (6) 1/8”HolesWhile you still have the milling plate attached, put a 1/8”drill bit in the chand spot dri

26、ll the (6)1/8”holes as indicated the template. Remove the milling plate and finish drilling the holes to a depth of .625 usingthe same process as before.7thOperation: Drill (2) ?”HolesPut a ?”drill bit in the chuck and dthe (2) ?”holes as indicateOn the templateto a depth of .625*1*18Operation: Mill

27、 the ShelfReattach the plate with (36)1/8”holes and mill the reahelf to a depth of .630”using the sameprocess as before. Some of the shorter en dmills are not long eno ugh for the drill chuck to clear to buffer tower.Due to size differences in different chucks there isn t a theivsmsmillength.you hav

28、e is too short, just do as much as you can and finish the rest with a dremel. I was lucky and had a Ion geren dmill so I just used it.th9Operation: Drill Fire Control HolesUsing a 5/32”drill bit, drill the holes for the hammer and trigger pins through each side of the fixture.Drill each side of the

29、receiver separately. Trying to drill all the way through both sides of the receiver at one timewill cause the drill bit to walk, and your holes may not be in the correct locati on.10Operation: Drill Safety Selector HoleUsing a 3/8”drill bit, drill the safety selector hole using thneesarocess describ

30、ed in operation 9.11thOperation: Trigger SlotTurn the fixture over and locate the 1/8”hole that you drilled all the way through in operation 2.Option 1: Drill a second 1/8”hole .365”toward the front of the recEivsTtfrouf this hole.Then use a 5/16”drill bit to enlarge both holes. You can then use a f

31、ile or a dremel to remove thematerial left betwee n the holes.Option 2: Drill a second 1/8”hole .365”toward the front of thmriheBivairtfroof this hole.Use a 3/8”drill bit to enlarge both holes. Then use the 3/8”endmill to connect the holes.clamp some guides such as a 2x4 to your drill press table to

32、 help you keep a straight line.Measure forward .365”from the center of thdno/e and scribe a line.Then find the center line of your receiver by measuring the width and dividing that in half. My half measureme ntwas .455”. Yours should be very simSaribe a line there in tersect ing the other scribed li

33、ne.Drill the second 1/8 ” holethis intersection, and then enlarge both holes to the size depending on your optionchosen. I ll be using option 2, so I enlarged mine to 3/8”.Heres a picture of my make shift guideYou can also see how the (2) 3/8”teotely juSirtectand leave material between them. I clamp

34、ed a wooden slat to the drill press table as guide. Lower the 3/8”endmillinto one of the holes, then slowly move it to the second hole.童th12 Operation: De-burr the Trigger, Hammer, and Safety Selector HolesThis is an optional step, but I have found it the easiest way to create nice looking holes.Rem

35、ove the receiver from the fixture.The holes you just drilled probably created some burrs on the outside of the receiver. You can sand these off, butthis creates variations in the finish of your receiver, especially if you are going to anodize it. Take a large drill bitand just barely tap the holes.

36、This will quickly remove the burrs and provide a slight coun ter sink. Just tap the drillbit on the hole lightly once or twice un til you are happy with the result.Attach one side of the fixture plates at a time to the side opposite you are drilling. This will give you a flat surface forthe receiver

37、 to sit on.The size of the drill bit is not important as long as it several sizes larger than the hole. Just use whatever you have.You will have to use a differe nt size for the safety selector hole because a bit big eno ugh to deburr that hole willhit n ear by features of the hammer pin hole.th13 O

38、peration: Smooth Fire Control PocketNow you will probably need to smooth out imperfections in the fire control pocket. You will get better at themilling process the more receivers you do and eventually can skip this step. The quickest thing to use is adremel with assorted sanding drums. Keep the dru

39、m moving all the time and don too much material. You want tosmooth it out, but once your gun is assembled, you won this. So don t sand so much that you have tlsiiowaurreceiver because you tried to smooth out someth ing that you will hardly ever see. The width of the pocket shouldbe .690a fewthousa n

40、dths over this, but too much will cause slop in your trigger and hammer. In extreme cases, this could bedan gerous.Here is the fini shed fire con trol pocket. This is probably best look ing pocket IYou lear n by your mistakes and each time you will pick up somethi ng that you could do differe nt to make thingsa little easi