I was messing around this weekend trying to fix the wheel set-up on my portable band saw. Long story short, I tried 3x time to get started a nice perfect set of threads on the 1/2" stock I was using for the axle. All three times, they were just a little off. Is there a tip/trick to getting a hand die to start correctly on a piece of stock? Curious for I'll be making a bunch more rods and little pieces in the future. Thanks.
Drill through a block on a good drill press or a mill if that well connected. Without moving block, chuck tap and turn it in by hand. Now you have a guide.
There are tap guide tools also, available from places like MSC Industrial supply. Some are in a human price range
i had to think about this for a few minutes...the problem made me realize how much i take for granted having unlimited access to macines tools. every solution i was coming up with required machining something! so far i came up one half-assed idea that requires no machining, using junk everybody has laying around the shop: make a threading fixture out of a piece of angle iron that will hold your round stock. drill a hole the diameter of your round stock in a piece of flat stock, say a 4" long piece of 1/4 x 2. set your round stock in the v of the angle iron, slip the hole in the flat stock onto your shaft, weld the flat plate to the angle iron, of course making sure it's good and perpendicular. to use, clamp your die handle/die to the flat stock, and use a vise grip or whatever to turn the roundstock into the fixture/die assembly, instead of trying to turn the die. make any sense?
bruce has ya covered here. (as usual) only thing to add would be sometimes using the chuck key helps when you need that little bit of extra leverage. do not power tap with your drill press
The chamfer is a good tip, also start with it a little long and grind off the first couple of threads. You may notice the die self-corrects misalignment by the third thread or so. Good Luck
I think you are tapping bar stock from end, not what I was thinking at first, so using a simple block is less than perfect...how about thicker block, drillit to tap size, then drillit halfway through to barstock size to drop onto end. THicker would be better, though I doubt the tapered seat left by drill would affect puttin it onto bar end.
maybe the problem is my reading comprehension, but banjorear seems to be talking about starting a DIE and bruce talking about TAPS.
Danged if you ain't right! Well, I'll rearrange his design to use my tool...free! Guess Carroll Smith knocked dies out of my mental agenda. So--there are die wrenches with a guide, but I believe those are integrated, not an add-on. Hmmm...take the block of metal I just ruined for a non-existent tap...drillitout to size of the bar, all the way through. Again, thicker is better. Hold it against die, eyeball accurately centered. Mark where two opposite or semi-opposite, depending on design, relief holes in die fall...use two small machine screws through holes into tapped holes in block. Tighten enough so die is flat against block but can squirm around to find center. Use. See, I'm determined to use that piece of metal I started with!
If you have access to a lathe, a trick I always used was to mount material in the headstock (chuck) and then remove the center from the tailstock. The tailstock spindle will give you a flat, square surface perpendicular to the stock (axle). After chamfering the stock slightly, place the die with the holder up against the stock and methodically (by hand) turn the chuck and advance the tailstock spindle keeping slight pressure on the back of the die. Works for me!
I use the lathe as described above, but thinking you may not have a lathe, How about a short piece of angle, with the end nice and square. You might be able to use it to keep the die square as it starts. Or at least give you an early warning if it startts going off centre. A generous taper, as mentioned above helps a lot too.
if you are using a die NUT you are in fact using the wrong tool. A Die nut is merely for cleaning up threads was never invented for cutting threads .for that you need Thread Dies . Die nut. the proper tool for holding them is called a "stock" . I never use Die nuts for anything,if a thread is damaged i can make another on the lathe or i use a a proper "Stock and Die " which is adjustable to make a new thread. Now days the only thing available are adjustable "ring" dies which to my mind are inferior to the seperate dies available until about 10 years ago. With the proper adjustable dies you start the thread on a taper (ALWAYS!!) at the wide open point,then cut the thread using a tallow based thread cutting lube.The old 1/4 in ,back 3/4 rule is most important if you want to cut a clean thread . After the first cut you measure with the calipers to ensure the root depth of the thread is correct,and as it's the first cut it will be too big. NEVER use a die nut to determine the thread size because all die nuts are in fact undersize and your thread will be too loose. The next cut is to cut to almost the correct depth,use a ordinary nut to make sure it's OK .then clean the dies and make your final cut slowly. If you are cutting threads con a axle which will no doubt be a high carbon steel,it is most important to use only HIGH quality tools. you'll fuck a good axle if you use cheap shit tools from china. This is a ring die ,not my favorite type of tool because it only gives .003 thou. difference in adjustability. you can see the adjustement screw on the other side.More info here; http://www.icscuttingtools.com/Dies.htm you should cut your starting chamfer to the same size as the chamfer in the die. To get the Stock set up before starting the thread I use a small set square,place the square against the job so the right angle of the square tight is under the stock ,get some one to hold it for you as you start the thread cutting.Check it a couple of times to ensure it's OK . Sounds like work? sure but what do want? a good job well done or a sleazy job done quickly which will come back and bite you?
Got a drill press that drills square? You probably do, but I've seen some that are off a touch. Pull the power cord if necessary or make darned sure you can't hit the 'on' switch while you're doing a manual operation. Back the drill press chuck jaws all the way off. Set the axle stock vertical in the drill press. You can do this with a large piece of angle thats close to or right on 90 degrees. Clamp or bolt your drill press vise to the angle piece. Or if you can, lay the vise on its side and clamp it down. Use the accuracy of the vise to get a straight up and down vertical thats right on the money. Shoot the angle with a good accurate square. Hold the die on the axle stock. Use the flat area of the drill press chuck - jaws fully retracted as above - to hold a little down pressure on the die. Start threading lowering the chuck as you go. A little oil works fine with moderate pressure. Once you've started about a half die thick worth of threads you can revert to threading as usual. Won't hurt to remove the axle w/die from the drill press and clamp it in your bench vise. I do this quite a bit with my lathe when I start big dies. And as above, once the die has a good start I take it out of the lathe and over to the vise. You can see how you're doing by observing the threads after some are exposed with the die down the axle. Or . . . if the threads are short, spin the die off and see if one side has more thread depth than the other. If that's happening you have crooked threads.
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