Square Holes!

round holes machinists the world over love them can't get enough did you know in the English language alone there are over three ways to say hole that's not even counting the ventriloquism way although I've been excited to discuss rounds holes with you sitting here in front of the camera I worried it might be a bit of an advanced topic instead of getting ahead of ourselves let's start off with something simpler not round round holes in particular square round holes this video may end up a bit dark I tripped over one of the only two lights that I own and smashed it to pieces we've broached the subject of not round holes before quite recently actually this tool as shown does a pretty good job of making hexagonal holes or hexagonal for you worldly types but I need a square hole of a very particular size however I don't have a square broach perhaps you're starting to see the pickle I'm in before we start weeding neck-deep in the finer points of rotary broaching let's recap the big picture there are a lot of ways to make not round holes and by a lot I mean two or three this is the vise handle I made many moons ago I started off with a round hole and filed it square not my first time doing that probably won't be my last but always stinks to do this motley mix of shapes also started out as round holes and we're also opened up with a file but we're done on a filing machine [Music] this is my thousand pound filing machine not to be confused with this thousand pound filing machine and this is my two pound rotary broach fun fact these two things cost me about the same price mostly because everyone wants one of these and no one wants one of these these two pieces of equipment aren't always interchangeable meaning the filer can't always do what a rotary broach does and a rotary broach can't always do what a filer does which is why I have both still doesn't cover 100% of my bases not by a longshot but better than nothing fortunately for my immediate and pressing square hole making needs the rotary broach should do nicely meet me back at the bench so yes rotary brooches are expensive but if you're patient you can get lucky and come across them used or you could build your own they're really not that hard to make if you have a lathe and some patience search for a DIY rotary broach or broach plans and see for yourself mine came with some hex brooches if I came with I mean I had to pay for those too you just put in the size you need and go to town now try as I might I could not manage to get any of these hex brooches to make a square hole so I'm going to have to make a square broach this my friends is where our journey begins this particular broach uses 1/2 inch shank tools that is half-inch diameter I have plenty of half-inch broken or burnt up end mills and some half-inch high speed steel blanks these brooches are all exactly the same length that consistent overall length is very important to the operation of this thing and for now I think it would just be easier to start with a high speed steel blank then try to carve that chunk out of the center of an end mill I think my first step will be to cut a square on the end of this of the size that I need maybe a little more square than that technically what I'd like is a half inch square broach I can't fit that in a half inch round for now I'm gonna try something smaller 7 millimeters and see how that goes then maybe we'll tackle the bigger one challenge number one if you've spent any time around high speed steel you might know this stuff is tough to get along with it's extremely hard for you numbers people this is probably a Rockwell high 50 low 60 that would be off the charts if the scale stopped at 40 but it doesn't nice dog yes behold my digital friends what you see before you is a classic this old Tony no compromise mediocre set up and that's putting it mildly this isn't necessarily the wrong way to do it but there are better ways I could have come up with a lot worse let's put it like that the high speed steel is mounted in a square collet block because I want to make a square if I wanted to grind a butterfly shape I'd be using my butterfly shaped block that's what we call science as if wanting a square isn't enough I also need to add some taper some back relief I need the business end of the square to be the biggest part and the rest sort of taper away ideally I think I'd need about a one and a half degree clearance angle but I'm using my angle blocks and I don't have a one and a half degree block I've got a one and A two and A three but no one and a half degree so I'm using the two one would be too little and three would be Colin Furze that's a slippery slope so the blank in the collet block sits on the angle block so it's tipped the right way to give me the relief that I want and they're both clamped in my grinding vice vice is held firm to the magnetic Chuck the truck is currently on it's not going anywhere the magnetic chuck is bolted to the table the table is attached to the grinder which is bolted to the ground the ground is attached to the earth which is an insignificant speck hurtling through cold empty space and there's what it looks like not too bad I don't think it's square dimensionally it's right on and I gave it about 5,000 I do regret not giving it a little bit more but that's what we do these little test runs for I guess anyway next up is to add some clearances to the face to the business end I've got to sort of dish out the front a bit if you take nothing else away from watching this channel remember to be a hobby machinist you got to know how to dish it out and this might not be it but we'll try the blank I just squared is now loaded in the spin deck sir the vise is gone and it's clamped to the magnetic table not going anywhere that's a resin bonded diamond wheel not the best option but it's the smallest diameter that I have and it's not in great shape so I'm not worried about ruining it feels like I'm doing nothing oh no I think something's happening it's not a very deep dish unfortunately dishing it out sometimes entails raising your voice this is a tool post mounted die grinder with a cutoff wheel this is a smaller diameter than I would have liked but it's the biggest I've got for this tool you may be wondering this old Tony isn't that going to get abrasive material everywhere on the lathe ways in the Chuck in your hair well yes yes it will [Music] [Music] [Music] one of these two is a store-bought hex brooch the other one is a homemade square can you guess which is wig round in a small flat for the set screw on the rotary broach and just broke the sharp corners spun on a little bit of a chamfer and then just hone the business-end on a bench stone nothing left to do but I don't know if the same rules apply for square brooches as they do for hex brooches but for a hex the pilot hole is drilled I think 3 percent over the flat 2 flat dimension [Applause] this is roughly three percent bigger than seven millimeters closest drill I have is a nine thirty second scratch that I just looked it up four square brooches it's 10% since I'll have a seven point seven millimeter drill the closest match is a letter N well it's squarer than it was before that one in pretty easy makes me wonder if I could have gone a bit tighter on the pre-drill stuck with my 3% instead of moving to 10% fast forward three minutes and I cut a small taper along the length there's the square socket that was just broached and the rest of it is turned very similar to the Andals we did on the tap wrench now I'm just gonna try to put a small tight bend in the end of this turning it into one of those old-timey wrenches you always see at flea markets and never knew what they were for I'm gonna heat this with the torch and to keep that socket from buckling I'm gonna use my two in one old-timey wrench bending jig the jig is already set for about 45 degrees and there it is I should have probably found a different colour scotch-brite to film against I just wire brushed it and gave it the old cold blue treatment let's go see if it fits why yes I do leave my die father running all the time this filer uses the seven millimeter square head grub screws to hold the files in this collet sort of thing and then the file holder in the machine since all my files have different tapers back at the tang I have to constantly adjust them to get them to run true which isn't a big deal of course until now I've been using these cute little seven millimeter craftsmen these might be ignition wrenches but this is the second one I'm on I had two sets I lost the seven millimeter who knows where that ended up somewhere in the die filer clockwork probably but I thought it'd be fun to make a custom wrench for the machine could I've just changed out all these adjustment screws to hex head but you know what's really cool this wrench is now slightly magnetic so I can stick it anywhere on the machine and never lose it again boys guys dog [Music] [Music]

Channel: This Old Tony

Views: 1,816,959

Rating: 4.9283071 out of 5

Keywords: square holes, rotary broach, broach making, surface grinder, HSS, die filer

Id: DgB1psCFC7o

Length: 12min 34sec (754 seconds)

Published: Sun Feb 23 2020

Reddit Comments

[u/comando345]

This Old Tony is so underrated, his videos are fantastic. Plus he is so classy that I could show this to my Grandmother without worrying.

[u/dkramer0313]

man this is how you make educational videos. if you asked me if i EVER wanted to watch a video about making a square hole, id have told you to get bent. this guy makes it fun, i like that.

[u/Turtletree]

Ahem, (woodworker, turning in particular) here. I understand from watching AVE's video how broaching works, but what is the advantage/how does rotary broaching work?

Pardon my small brain.

[u/avgas3]

Words cannot describe my love for This Old Tony videos

[u/The_cogwheel]

Who says you cant drill a square hole? I mean it's not drilling, its broaching, and it's not square - the side walls are scalloped because his drilled hole was a touch oversized....

But who says you cant broach a somewhat square hole?

[u/NorCalDC13]

I am not a home machinist but I thoroughly enjoyed that entire video!