Junksmith Posted February 28, 2015 Share Posted February 28, 2015 (edited) I'm in the middle of a garden trellis that requires pieces of 1/2" round bar to intersect perpendicularly at a few spots. The plan all along has been to slit the horizontal pieces of 1/2" round so the solid pieces can pass through vertically. Essentially a section of grate.What's killing me is slitting and drifting the round bar. I can make a single hole that's not too off center, but I need three in a row and can't get them lined up. I drilled pilot holes which was probably a mistake.the essential question is, can I take a length of 1/2" round bar and put 3 roughly aligned 1/2" holes in it? Wish I could use square.thanks Edited February 28, 2015 by Junksmith Quote Link to comment Share on other sites More sharing options...
Michael Cochran Posted February 28, 2015 Share Posted February 28, 2015 I've never been there but just a quick suggestion you can use or ignore. I'd take a small try square and run it down the length of the bar with a scribe of some kind right in the corner. It might not be ideal or perfect but it might help. Quote Link to comment Share on other sites More sharing options...
Crazy Ivan Posted February 28, 2015 Share Posted February 28, 2015 You can always tweak the hole alignment in the bar after all your holes are drifted. Round bar won't show twisting as drastically as square would. As long as you're close, it should be fine for what I am picturing. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted February 28, 2015 Share Posted February 28, 2015 (edited) As long as the holes you punch are in the center of the bar and the right distance apart - don't worry about them being at the wrong angle as you can heat the bar and twist it to orient the holes and with round bar you won't be able to see the twist for correction. Otherwise if the distances are off.... All you need to do is either upset between the holes if they are to far apart or a few hammer taps between the holes as you turn the bar to stretch the bar if the holes are to close to each other. It's not as big of problem as you think, more critical to punch the holes on center and even if that is off one can adjust that if needed. It's all fun in blacksmithing. Edited February 28, 2015 by jeremy k Quote Link to comment Share on other sites More sharing options...
Junksmith Posted February 28, 2015 Author Share Posted February 28, 2015 Thank you everyone. The pilot holes weren't the greatest idea, but at least they'll be on the inside. Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted February 28, 2015 Share Posted February 28, 2015 Greetings Junk,You might try forging a small flat on the round bar before marking both sides with a center punch . And yes the distance veries and you must allow for change between holes . Test pieces., After punching and drifted I use 2 ball pien hammers , One mounted in the vice and one as a top tool to shape the pass through bulge . Works great. Keep up the practice on test pieces and perfection will follow.. Forge on and make beautiful thingsJim Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted February 28, 2015 Share Posted February 28, 2015 (edited) As the others have said the almost invisible twisting on the round bar will get you out of the post-punching alignment problem quite painlessly.There are also things you can try to prevent the misalignment from happening...I often mark along a round bar by laying it on the bench and fixing it so it cannot roll. Then taking a long piece of chalk or sometimes a brass bar and holding that horizontally scrape a mark down the top of the bar.If you feel you cannot hold the marker steadily horizontal you can use another chump of 1/2" and rest one end the chalk on that.Alternatively a chump of 1/4" flat or square bar and run it along the bench holding it against your 1/2" round bar as a scriber height gauge/guide. Lots of other permutations of course.The other thing you may find useful is to clamp or weld a tee piece on the end of the rail temporarily and that will prevent the bar from rolling out of line while you are punching. Maybe poke a bit of round through the first hole as a tell tale so that you can see it is maintaining alignment as you punch the subsequent holes.You will know about quenching out the thin side of an off-centre punched hole so that the thicker side does most of the stretching whilst drifting it out, that seems to magically bring the hole back into the centre.Alan Edited February 28, 2015 by Alan Evans added 'of' Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted February 28, 2015 Share Posted February 28, 2015 Slitting in a Vee block also helps keep everything oriented prior to drifting the hole to size. One of Otto Schmirler's books has a drawing for a jig to punch round - IIRC, it had a spring loaded plate that slid out of the way as the punch went through the piece. This offered more support while allowing the punch to advance. Quote Link to comment Share on other sites More sharing options...
Junksmith Posted February 28, 2015 Author Share Posted February 28, 2015 All wonderful ideas. Alan, yours in particular are going to be a game changer. Mr. Woolridge, I do have a v shaped jig made of angle iron welded to a flat. I just need to weld on a bit of a stabilizer so it doesn't walk on me. Quote Link to comment Share on other sites More sharing options...
Crazy Ivan Posted February 28, 2015 Share Posted February 28, 2015 If you have an anvil with a hardie hole, just weld a piece of bar that fits the hole. Close enough is good enough for what you are using it for. Quote Link to comment Share on other sites More sharing options...
SJS Posted March 1, 2015 Share Posted March 1, 2015 You could tack weld a bar parallel with the axis of the wholes so that you can accurately see while you are punching. The same effect could be achieved by clamping a big pair of vicegrips on the end of the bar and it would always hang in the same way, so all you have to do is punch straight. You might want a stock rest out past the vicegrips, plus that will give you both hands free for punching. You could leave the stock long and cut to finished size after punching and drifting. I would use a round swage the same size, or a little larger, not a V block... Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted March 1, 2015 Share Posted March 1, 2015 Vee block gives a little space between stock and chisel tip so you don't damage the swage. The stock is also less likely to turn because it's only touching along two planes - just like holding round stock in square jawed tongs. Smaller surface area for a given force and all that jazz... Quote Link to comment Share on other sites More sharing options...
arkie Posted March 1, 2015 Share Posted March 1, 2015 If you search the Blueprints, particularly those by Hofi, I believe he shows how he punches and drifts round rod. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted March 1, 2015 Share Posted March 1, 2015 I forgot to say that one time I bent the bar into a softish curved right angle in the middle, so one leg ran along the anvil and the other was supported on a trestle which also stopped it from rolling around, I suppose just leaving an extra few inches on the end and bending that at right angles would also work, just cut to length after punching.So many ways to kill a cat…you need at least ten to be effective… Alan Quote Link to comment Share on other sites More sharing options...
arftist Posted March 1, 2015 Share Posted March 1, 2015 You probably will not be happy if you don't upset the area before you drift it. Quote Link to comment Share on other sites More sharing options...
arkie Posted March 2, 2015 Share Posted March 2, 2015 .......You will know about quenching out the thin side of an off-centre punched hole so that the thicker side does most of the stretching whilst drifting it out, that seems to magically bring the hole back into the centre.Alan That's a neat tip Alan. Most of my problems with punching have been keeping them dead center. Thanks for posting it. Quote Link to comment Share on other sites More sharing options...
SJS Posted March 2, 2015 Share Posted March 2, 2015 I wouldn't worry too much about round punching into a swage. But I do remember punching into a V-block and it distorted the bar more than I liked... YMMV. I punch flat on the anvil and then move to the pritchel hole, I would expect to be able to do the same in a swage. If I was slitting and drifting to try and maintain the most mass around the hole, then I might worry about damaging the swage. Otto Schmirler, Werk und Werkzeug des Kunstschmieds, has TONS of cool took pics, and is one of George Dixon's favorite books, it also has pics of swage bolsters for punching round, and round on the diamond... Lots of tools that you can make to make this easier:-) If you had a handy dandy induction heater upsetting the middle of the bar in a very defined series of spots would be a piece of cake, I don't have one yet... (either;-) Instead I would play with it and slit it, and then open it, then upset it back open more, then drift to finial size, and see if that doesn't get you where you want to go with minimal thinning of the sides and distortion... Francis Whitaker used three tools to do his drifting. A slitting chisel that was 40% over sized for the hole, so for a 1/2" hole the diameter (pie r squared) is about 3/4", but Francis would jump that up to about 1" I guess. Then you need an opener, this is an undersized slitter that starts to round the hole a bit, just to begin to open it up. Then you take a heat and upset the hole so that it opens up nice. Then you can drift the hole to finished size. With minimal distortion, and thinning of the sides. It would likely look better if you upset the bar slightly before slitting, but you can probably get away without doing it using that technique... Check it and see if you like it... Like Alan said tons of ways to skin a cat... just depends on what you have, what you are willing to make, and how long you are willing to put into it. Quote Link to comment Share on other sites More sharing options...
Dodge Posted March 2, 2015 Share Posted March 2, 2015 (edited) If you want to get dead on, get one of these:This is a high dollar one but they make less expensive ones but either one will make a center punch mark on the same line along the length of any round stock provided you keep the stock stationary throughout the marking sequence. Edited March 2, 2015 by Dodge Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted March 2, 2015 Share Posted March 2, 2015 That's a neat tip Alan. Most of my problems with punching have been keeping them dead center. Thanks for posting it.Thin side quenching has got me out of a hole on many occasions it works best when the punch takes out a rounded end slug of course. If you use a sharp edged chisel to make the initial cut the vee at either end will remain off centre but the hole itself will be better centred. Alan Quote Link to comment Share on other sites More sharing options...
carlson Posted March 30, 2015 Share Posted March 30, 2015 What if you got 6-12 inches of metal tubing just big enough for you stock to slide through and cut out a pencil/marker size slot down the length of it. That would let you get a straight line. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 30, 2015 Share Posted March 30, 2015 The easiest surest way I know to mark straight lines down a round section without special tools is to lay in in or on a piece of angle iron and use the angle as the guide. Making opposing marks is trickier but not so hard. Wrap a piece of string around the piece and mark it with a pen so the ink marks two positions on the string. Now unwrap it and fold it so the ink marks are touching. The crease between the marks is the center, mark it there. This gives you two story marks that will be diametrically opposed when wrapped around the original stock. The larger the diameter the easier but this trick works pretty easily down to 1/2" dia.Oh, NO do NOT use a sharpy or such, and old school Bic ball point is perfect you don't want the ink soaking outward into a smudge.Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted March 31, 2015 Share Posted March 31, 2015 What if you got 6-12 inches of metal tubing just big enough for you stock to slide through and cut out a pencil/marker size slot down the length of it. That would let you get a straight line. I posted an unnecessarily snarky comment questioning this which hasn't appeared for some reason I am pleased to see. I am not quite sure how you envision your sleeve in use? If one has a few feet of bar to mark in order to keep the holes in line how does your slotted short tube work? Is it not liable for incremental error /rotating around the workpiece? How do you mark the slot out to start with, another slotted tube?The advantage of both Frosty's angle iron and my bench / flat bar solutions mean you can mark the full length of your workpiece in one go. Like Alan said tons of ways to skin a cat... No I didn't! I said you have to have at least ten ways to kill a cat. It is why Vets charge so much to put one to sleep….cats have nine lives… sorry, mixed metaphor and a poor reference to an awful joke!Alan Quote Link to comment Share on other sites More sharing options...
ianinsa Posted April 1, 2015 Share Posted April 1, 2015 Alan, if you read the book ' 101 uses for a dead cat' you might be able to use said dead cat to help 'scribe the line?However if one puts some of the above ideas into a joint solution you might have a winner! ie. mount tube no table screw in a self tapping screw so it just touches the bar, clamp 2 'vice grips' horizontally on the bar and 'draw the bar through the tube and the screw will 'scribe a line ' along the center of the bar Quote Link to comment Share on other sites More sharing options...
Frosty Posted April 1, 2015 Share Posted April 1, 2015 That works Ian. A tap wrench works well in place of the vise grips if it's large enough to grip the round.Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted April 1, 2015 Share Posted April 1, 2015 (edited) That would really set my teeth on edge, I can just hear the shriek of the meow sound as you pull the bar past the self tap...So rather than mounting the slotted / self-tapped tube to the bench, why not just drill a hole the right size through a rectangular block which would easier to mount / not liable to rotate at all?….or…if the bench is flat enough to keep the bar unrotated when held by tap wrench or vice grips you may just as well leave the bar stationary and run a half-height block and scriber along beside it…..or make or go out and buy a a nice Brown and Sharpe or Starret or even Eclipse adjustable scribing block. I use mine off the bench most of the time…very rarely off its proper surface plate.An excuse to buy another toy…win win!Alan Edited April 1, 2015 by Alan Evans Quote Link to comment Share on other sites More sharing options...
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