R W Posted July 10, 2011 Share Posted July 10, 2011 Need a 3/4" square hole through the centre of a piece of round bar 2"dia x 3" long. Have bored a 3/4" hole through the centre. Any advice on heating, punching etc would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted July 10, 2011 Share Posted July 10, 2011 drift with a square shaft. Quote Link to comment Share on other sites More sharing options...
MattBower Posted July 10, 2011 Share Posted July 10, 2011 Is it crucial to maintain the current outer dimensions? If not, then what Steve said. If so, then you might consider squaring it out by filing. Quote Link to comment Share on other sites More sharing options...
781 Posted July 10, 2011 Share Posted July 10, 2011 At the ABANA 2010 conference at Memphis Mark Aspery used a cape chisel to cut out the corners to make a square hole. Not sure if he has a youtube video of doing this Cape chisel has one flat side and the other side is wierd but once you saw one you know what it is Quote Link to comment Share on other sites More sharing options...
pkrankow Posted July 10, 2011 Share Posted July 10, 2011 A diamond point is meant to open up corners. It may be called something else as well. Chiseling out with cold chisels is interesting work, I have done it in an ASO that needed a hardy. Phil Quote Link to comment Share on other sites More sharing options...
K. Bryan Morgan Posted July 10, 2011 Share Posted July 10, 2011 What I've seen done is, drift the opening with the appropriate sized drift then using an upper and lower square swage, swage so that the opening conforms to the size of the drift tightly. Quote Link to comment Share on other sites More sharing options...
R W Posted July 10, 2011 Author Share Posted July 10, 2011 Is it crucial to maintain the current outer dimensions? If not, then what Steve said. If so, then you might consider squaring it out by filing. Would like to keep the outer shape as near as possible. Quote Link to comment Share on other sites More sharing options...
MattBower Posted July 10, 2011 Share Posted July 10, 2011 Then I'd file or, as someone suggested, chisel it, then finish with a file. A square broach would also be a good solution, but if you had that capabililty you probably wouldn't be asking the question. And setting up for broaching a hole that size isn't something you'd do for a one-off. ($$$) Quote Link to comment Share on other sites More sharing options...
polygon Posted August 2, 2011 Share Posted August 2, 2011 ever considered rotary broaching for an application like that? It's a little too deep for a typical broaching tool, but may be worth investigating Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted August 3, 2011 Share Posted August 3, 2011 Drift with tapered sq punch then reheat, put the drift back in and hammer the sides back to "spec". (Of course then the tickness may be a bit off and you can then flatten and re-drift----repeat until satisfied or you just give up!) Quote Link to comment Share on other sites More sharing options...
dkunkler Posted August 3, 2011 Share Posted August 3, 2011 Drift square as others have said and true up the outside by turning the bulges off in a lathe. Rotary broaching looks cool but very expensive, also the broach depth would be a problem. Quote Link to comment Share on other sites More sharing options...
dkunkler Posted August 3, 2011 Share Posted August 3, 2011 If the application doesn't require the hole to be square all the way through, you could bore the middle portion to a larger inner diameter on a lathe. Squaring just the two ends would be much easier. Quote Link to comment Share on other sites More sharing options...
John B Posted August 3, 2011 Share Posted August 3, 2011 I think the "Forging" a square hole as already been well covered, so how is the project progressing? As Machining has started to creep into the options, how about using a slotting machine or a shaper? or electro machining (EDF?) all of these will not distort the outer diameter of the shaft and are very accurate. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted August 3, 2011 Share Posted August 3, 2011 Post a picture and your method of choice when done please. Phil Quote Link to comment Share on other sites More sharing options...
Larry H Posted August 3, 2011 Share Posted August 3, 2011 Hind sight is 20 / 20........ 1/2" hole would have been best..........for that method.........you probably won't get a 3/4 sq. hole from what you have now Quote Link to comment Share on other sites More sharing options...
anvil Posted August 7, 2011 Share Posted August 7, 2011 I would slit it, upset the slit, then drift it first round, then square. Francis's cookbook gives lengthways for the hot slit. This will give you about half the thickness on the sides and looks great. If you punch or drill the hole first, you lose a lot of material. Oops, just noticed the 3" length. In thus case, start with a longer piece, then do the above and cut to length you need. If you don't want to change the outside dimension, you could drill to 3/4",then make a shearing tool that has a 3/4" tennon on the end and is 3/4" square above and hardened. This will remove the corner material using an 8 lb hammer or so. When I have done this, my tool is handled, but can be hand held as well anvil Quote Link to comment Share on other sites More sharing options...
SmoothBore Posted August 8, 2011 Share Posted August 8, 2011 Sounds like a job for a Die Filer. Quote Link to comment Share on other sites More sharing options...
dickb Posted October 25, 2011 Share Posted October 25, 2011 How do I punch and/or drift a square hole? I can forge a square punch or a square drift, but it's not a perfect square. The four faces of the square are slightly differant and looking at the working end, the two diagonals are not identical. I usually strike a few blows from one side (side 1) and then turn the work over and strike a few blows from the opposite side (side 2). The problem is, when I turn the work over to drift from side 2, the drift will not exactly fit the work because the drift was not exactly symetrical. I end up with a more or less square hole but the corners are a little rough. Having the hole not exactly square is okay, but I have to use a file to clean up the corners with a file. I'd like not to have to use a file to clean up the corners. Does any one have a suggestion, aside from forging an absolutely square drift? Thanks Quote Link to comment Share on other sites More sharing options...
JNewman Posted October 25, 2011 Share Posted October 25, 2011 Forging the drift square is a matter of practice. Make sure when you are starting to flatten the second side that you get it square at that point, it is much easier to keep it square than to correct it once it goes diamond shape. Working all four sides rather than just two can help as well. When you are drifting, drive it in, knock it out, then turn it 90 degrees and drive it in again. This will help to correct for any imperfections in the drift. If I want a square hole I prefer punching square rather than round, because it can be hard to get rid of a round mark on the flat sides of the hole. Quote Link to comment Share on other sites More sharing options...
John B Posted October 25, 2011 Share Posted October 25, 2011 If your punch is slightly out of square you are not going to punch from both sides and expect them to punch through square. You don't say how thick your material is, or what size square you are trying to punch, and how far in you are when you try to punch it from both sides Try punching as far through as possible, until it becomes very firm when struck, leaving mabe 1/16" thickness in the base, then flip it over and punch through using the dark or shiny spot as your location. If you haven't got a square drift, you need more forging practice, or file/grind it square and to size The punch should be smaller than the drift, Alternatively obtain a piece of stock the finished size of the square you require, taper at both ends and use that as a drift Quote Link to comment Share on other sites More sharing options...
MattBower Posted October 25, 2011 Share Posted October 25, 2011 John's suggestion is a good one. Or just dress your not-quite-square punch with a file or grinder until it is square. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted October 25, 2011 Share Posted October 25, 2011 Yes, it is easier to square the tools than to correct an inaccurate hole. If you must file the hole you could have filed the tool instead. I usually get mine quite close but finish by grinding to even better accuracy. Corners can often have a slight radius... depending on what fits into the hole. It is, again, easier to soften the corners of tenons than to keep a sharp cornered hole. Quote Link to comment Share on other sites More sharing options...
brianbrazealblacksmith Posted October 26, 2011 Share Posted October 26, 2011 How do I punch and/or drift a square hole? I can forge a square punch or a square drift, but it's not a perfect square. The four faces of the square are slightly differant and looking at the working end, the two diagonals are not identical. I usually strike a few blows from one side (side 1) and then turn the work over and strike a few blows from the opposite side (side 2). The problem is, when I turn the work over to drift from side 2, the drift will not exactly fit the work because the drift was not exactly symetrical. I end up with a more or less square hole but the corners are a little rough. Having the hole not exactly square is okay, but I have to use a file to clean up the corners with a file. I'd like not to have to use a file to clean up the corners. Does any one have a suggestion, aside from forging an absolutely square drift? Thanks Quote Link to comment Share on other sites More sharing options...
brianbrazealblacksmith Posted October 26, 2011 Share Posted October 26, 2011 I guess I pressed the wrong button. You could try punching a slot and then drifting with a square drift for opening up a slot. There are pictures of the tools in "Slitter Geometry" on the first page. Quote Link to comment Share on other sites More sharing options...
Dave Huntress Posted October 27, 2011 Share Posted October 27, 2011 so today I took a quick break from my regular fab work and decided to try out one of my punches I have. This friend of mine gave me a bucket of tools he had lying around his shop. Now he had worked for Vulcan Tool in Weymouth, MA. for about 25 years or so, they are a modern day blacksmith shop and make tools. So I have this 1/2" square punch I decide to try out. Pretty neat I'm thinking, I pre-drilled a 5/16" hole in the drill press thru a piece of 1" x 1/4" flatbar. I stick it in the forge for a heat and when it's ready I try punching it thru...came out really good... ya I know, no big deal but it was my first, I mean I used to run cnc punch presses at the sheetmetal shop and hadn't run a single station punch in a while so this was like way back in time so to speak I was traveling..... anyway, just sayin..... the tooling I have from my buddy are all heat treated so it's really a blessing I happened onto this stuff... I have an idea for making motorcycle shifter pedals for a future project..... cheers and thanks for reading..... Quote Link to comment Share on other sites More sharing options...
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