Machine Drill a Square Hole in Round Stock 705 tubalcain

hello once again this mr pete your internet shop teacher welcome back to the shop and in today's video i'm going to show you how to drill a square hole in a round stock well wait i just looked through my inventory and i am fresh out of square drill bits so i'm going to approach it a different way and i'm really getting ready for a project here in the future where i'm going to make a fixture and i want to be able to hold quarter inch square bits like this so i'm going to show you how to form or machine that hole and i'm going to do it simply in one inch stock without the flange here this will be in a later video let's step over to the bridgeport and see how that's to be done but of course in industry they would use a square brooch a quarter inch square brooch they would drill a hole bam broach it it would just take a few minutes but that broach is 130 from mcmaster carr plus shipping so you can count on about 150 for a broach that you might only use one time so this is how i will do it and of course you could do it this way for any size square hole that you desire let's go on over to the bridgeport be sure and wear your safety glasses and practice all of the other safety rules that i've talked about so many many times i'm going to start with a bar of 1144 stress proof steel and actually this is 30 millimeter the bar is a little longer than what i would have wanted and rather than chop it off first i'm going to chop it later so i've got it supported at the far end and i have about an inch and a half sticking out of the vise and there's a parallel underneath there and the first thing i want to do is take my edge finder which is half inch touch off and find the middle and once i do the touch off it'll be 842 thousandths over and i'll be on the middle for the remainder of the project all right i've touched off and now i'm going to move the work the table over 842 thousands that is the radius of the bar and the radius of the edge finder so i'm looking at the dro and moving 842 now i'm in the center of the work i will lock the table and it will remain there for most of the rest of the project i'm going to use this beautiful little niagara cutter quarter inch solid carbide so what i'm going to do here is touch off and then back off and i'm going to take multiple passes up to the white line until i get to a depth of 718 thousandths how did i find that dimension it is the radius again of the work plus half of the thickness of the key which is 1 8 of an inch so i've added 0.592 plus 0.125 for a total depth of seven one eight i will not show all of this it is so repetitive all right i've touched off and i'm going to mill about 50 or 75 thousandths at a time that is per pass i'm zeroing out the graduated collar on the knee and raising up now let's go 75 000 do not attempt to do this all in one pass or you will either break your end mill or it will wander off its true center okay here's the final pass already and now the acid test let's see if the quarter inch key stock fits looks good and let me get a view of it from this way to see if it appears to be on center and yes it appears to be on center doesn't it the next step is to take this piece of quarter inch thick steel and it's 1 1 8 long amount and i've got the key in the slot and i've already marked it here and i'm going to cut this off and the piece with the x is the piece that i want to keep and i'm going to pin it in place and then we'll machine the whole thing off okay the piece is cut and trimmed and ready to install but now i have to drill two holes two cross holes eighth inch holes and pin it so i have to rotate the work 90 degrees which is no easy job but let's put the rows index to work and i'll show you how i can rotate it accurately 90 degrees all right this is the rose index and they're available in two sizes this is the larger one has a capacity up to two inch notice that there's a bit of a v way and i can rotate it down 90 degrees or i make a hexagon that which is what how many degrees an octagon and you know whatever you want but i'm using the square part so i will put it over the work like this the table has to be perfectly clean and before i tighten up the brass tipped set screw i will take an accurate scare square and we're going to square it up and then tighten okay square it up and tighten next i will loosen the vise and the work can be rotated 90 degrees and this is quite accurate put the steric square on get it adjusted tighten the vise and i'm ready to lay out and drill as i prepare to mill the little pockets and then drill the eighth inch holes i'm going to put the key in place but first i'm going to put a piece of aluminum foil this is about 3 000 thick the reason for that will become apparent i think later on so i won't explain it now but now the key then this piece and then i'm going to clamp since i'm drilling eighth inch holes all the way through round stock it would be almost impossible to get the drill to start it would deflect on the round surface here so i'm going to mill just little pockets here one about where you see that line and one about this line and just enough to make a flat where the drill bit point can catch all right i've started both holes in the little pockets this is an eighth inch drill bit and i will drill all the way through all right that's done and i'll move down to do the other one but before i do that i will put a pin in here to hold the alignment and now the other one well i have both pins temporarily in place remember remember they'll be held in with loctite now if i would have to rotate the work back to the other position to make minor modifications in the slot it could easily be done because the rose index is still attached but i'm done here on the vice so i'm going to take it out and let's go over to the bench okay because of the fact that i use stress proof i'm assuming that the slot size cannot change that is get pinched shut or open up a little bit on me but there's the piece i'll clean it up real good i have to get these other things out there and i think you know why i use that shim so after everything is degreased thoroughly i'm going to go ahead off camera use this loctite on the pins and a little bit on each side of this now whether or not that does any good i really don't know but i'm going to go ahead and pin that in and tomorrow when i come back that will have the loctite will have hardened set cured not dried and then i will put this in the lathe turn it down round to no to a one inch rather and then cut it off turn it around and face it and then it'll be done see you tomorrow well it's the first thing in the morning and the loctite has presumably hardened set cured and the first thing i'll do will be to lop off the pins well i have the work installed in a four jaw chuck on the closing lathe and i'm within a thousandth or less and i'm ready to do a little turning well let's see how this worked there's going to be a little bit of thumping to start with and now i'm going to turn it down to one inch in diameter that's almost 200 000 that i have to take off that dimension isn't critical i just want it down in the ballpark but that will remove the the pins and and this bar that i put through there it'll just smooth it up make it look good i hope so and i'm down to just about an inch now i got 11 000's to go i'll do that off camera see if i can improve the finish just a little bit and now to face it off and it's done okay there it is let me knock off those internal burrs with a needle file and i'll be right back all right there it is and that's how to make a square hole without a brooch it takes a lot longer admittedly but notice that you can hardly see the joint or the pins so it turned out pretty nice now you could also make a rectangular hole by the same method and you could have the hole in the center or a little bit off-center or however you want it and it could be very long too you're not held to a rather short piece like you would with a brooch unless you have a specially made brooch the piece is going to have to be kind of short an inch inch and a half something like that this is key stock probably a little bit under size falls right through here is a quarter inch piece of high speed steel now you're going to see me do the same operation or i may omit it because i've already shown you in a future video where i make that grinding jig and the pieces will be something like this and they could be made in they really need to be made in four sizes three sixteenths quarter five sixteenths and three eighths but since quarter inch is probably the most common size of high speed steel i take it back this isn't high speed steel this is probably some kind of mild steel with a carbide brazed tip this is high speed steel all right hope you enjoyed the video perhaps you can use something like this in your machine shop of course it's going to take you twenty thousand dollars worth of equipment to do this rather than fifty 150 roach this is mr pete saying so long for now you

Channel: mrpete222

Views: 790,167

Rating: 4.8405509 out of 5

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Id: tnJMDtZelms

Length: 17min 44sec (1064 seconds)

Published: Sat Jan 16 2021