Rockgineer Posted November 25, 2009 Share Posted November 25, 2009 I am working on a metal handle that needs to have a 3/8"-16 threaded hole that goes 3/4" into the bottom of the shaft. The steel shaft is approximately 5/8" in diameter. I dont have access to a drill press or a lathe. I'm using a cordless drill and it is way too time consuming. Is there an easier way to make this hole in the shaft while the metal is hot? I was thinking about putting the hot piece into a vice and driving a punch into the shaft. then following up with a 5/16" piece of steel to make the hole the proper size for tapping. The steel will contract after cooling making the hole too small but i should be able to run the 5/16" drill bit with my cordless drill to ream out the hole a bit. Thread strength is not much of an issue I just need it to thread on to a 3/8"-16 threaded rod. Does any one have any better ideas or pointers? Thanks, Brad Quote Link to comment Share on other sites More sharing options...
jeremy k Posted November 25, 2009 Share Posted November 25, 2009 Brad a cordless drill will work just fine - use a small pilot hole first like maybe 1/8" then step up to the size needed for the 3/8" thread ( If I recall without a chart in front of me it's a 5/16" drill for a 3/8" tap) - JK Quote Link to comment Share on other sites More sharing options...
blazerbud Posted November 25, 2009 Share Posted November 25, 2009 I think the easy way is with the drill press as you said, but you made me think of something. It probably won't help your situation, but I wonder if it is possible to have a hole that is enlarged to fit over a bolt thread, then fit your piece while it is hot over a cold bolt thread and close it down on the bolt thread gently, while twisting the bolt. Then when it is cool enough thread it on out. I don't know. Just me personally, If I didn't have the right tools available, I would go to friend who did and do it the easy way. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted November 25, 2009 Share Posted November 25, 2009 Is this mild steel or something harder? For holes this size you need to set the motor to a slow speed so it can bite in properly. Cool with water, not oil. For that short of a hole in mild just use a water bottle and make a small puddle. If the water is gone stop and add more. If the water is thrown out of the hole before you can cut you are spinning the bit too fast. If you are using a good drill bit then it should cut nicely. If it starts spinning then you work harden the surface and burn up the bit, even in mild. Adding baking soda or chalk to the hole can break the work hardening and get you going again but you may need to resharpen or replace your bit. If it is something harder use a ground carbide masonry bit with lots of water. No I'm not crazy. I have made holes in hardened materials recently (chilled cast iron), as well as mild steel, using a corded hand drill. In mild steel with a freshly charged battery and a solid work holder this hole should cut in about a minute producing a chip broken when you add more water. Oil immediately after working to prevent rust. With a hand drill you will have some concentric run-out so having an extra set of eyes line you up is a good idea if possible. Phil Quote Link to comment Share on other sites More sharing options...
Rockgineer Posted November 25, 2009 Author Share Posted November 25, 2009 well i have two factors in this that are causing the drilling to take too long. the steel was free and was a high carbon steel that is extremely hard. The second is my drill bits are not the best but they did work. I'm really just looking for a 'primitive' way of doing this. I like the idea of using a bolt to create the thread. i think the bolt would be near impossible to remove after cooling but definitely worth a try. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted November 25, 2009 Share Posted November 25, 2009 Modern bit in an old style brace? Made a lot of holes that way growing up, so many that my dad hid the brace! When he finds it he says he will give it to me. Phil Quote Link to comment Share on other sites More sharing options...
John B Posted November 25, 2009 Share Posted November 25, 2009 If the steel is hard anneal it after forging before trying to drill it Previous advice offered works. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted November 25, 2009 Share Posted November 25, 2009 Forging down around a bolt? I'd pay a dollar to see that! Only if you never want to get it out. Actually the part he's having trouble with is getting a hole in it in the first place. Now you want him to make a bigger hole? Hello!:rolleyes: Quote Link to comment Share on other sites More sharing options...
jeremy k Posted November 25, 2009 Share Posted November 25, 2009 I gotta go with Grant - save me a seat. - sorry drilling is best, on something that is that small doing it by hand with a cordless is very easily done provided it's not super hard stuff. - JK Quote Link to comment Share on other sites More sharing options...
ArtWerkz Posted November 26, 2009 Share Posted November 26, 2009 Mark the center of the piece and hit it with a center punch and start with a center drill if you have one and work your way up to the drill tap size required. If you are familiar with offhand grinding and have a bench grinder you can easily sharpen your drill bits. You can even make yourself a drill point gage out of a scrap piece of steel. You can google it to get a pic. They have an angle of 59 degrees as I have made my own. Hope this helps. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted November 26, 2009 Share Posted November 26, 2009 Get a good drill bit (not made in China), spin it slow (chips shouldn't turn color), keep enough pressure on it to keep a chip flowing, and that should do it. There has been a lot of discussion about water/oil/cutting fluids. Water and baking soda will work. but I use various cutting fluids myself. Been machining for 20+ years now, and different fluids can make a world of difference in how a piece cuts / tool life. What ever you use make sure you use enough to keep the bit cool. Learn how to sharpen a bit on a bench grinder, and you save time/money in the long run. It only takes a couple of seconds to touch up a bit, and have it cut 100% better. If all else fails, hot punch a larger hole, and weld a nut onto the end :rolleyes: Quote Link to comment Share on other sites More sharing options...
arftist Posted November 26, 2009 Share Posted November 26, 2009 The key is the anealing. Heat the end of the shaft in your forge or with a torch. Let it cool slowly, overnight is best, in a bucket of wood ashes, or dry sand. Tomorow, it will be as soft as it can get and a sharp bit will drill it readily. Caveat:, If it is truly a super hard shaft, it will likely still be pretty hard after anealing. Consider drilling a larger hole than the standard 5/16 (75% thread). Even slightly larger will reduce the chance of breaking the tap greatly. 50% thread is strong enough for most purposes. Quote Link to comment Share on other sites More sharing options...
Dave Leppo Posted November 30, 2009 Share Posted November 30, 2009 Weld on a nut? Quote Link to comment Share on other sites More sharing options...
merl Posted December 7, 2009 Share Posted December 7, 2009 My question would be " If you can't drill the hole how do you expect to make the threads in it too?" Can you just weld a nut on the end and then grind the flats off to hide it? I have been a skilled machinist for nearly 30 years and if I needed a threaded hole in the end as you do but, didn't have the tools to do the job, I would find someone that could do it the right way or modify the design to eliminate the threaded hole if I could. Could it be cross pined? Quote Link to comment Share on other sites More sharing options...
peacock Posted December 8, 2009 Share Posted December 8, 2009 Forge a 3/8 tenon on the end thread it with a die. The tenon is much easier to forge than a hole. good luck Phil Quote Link to comment Share on other sites More sharing options...
schweinfurth Posted December 9, 2009 Share Posted December 9, 2009 Before considering drilling and tapping on the lathe, I would thread the rod with a die, get a 3/8-16 coupling nut and screw it on. Alternately, you could weld a coupling nut on the rod. Quote Link to comment Share on other sites More sharing options...
Jocko 58 Posted December 9, 2009 Share Posted December 9, 2009 G'day I would go down to a machine shop get them to do ti ,half an hour all done and cheaper time wise Quote Link to comment Share on other sites More sharing options...
Ken Ra Posted December 10, 2009 Share Posted December 10, 2009 There is another alternative somewhat radical that I have heard of get a piece of graphite machined to the size and threads you need, then wirefeed weld around it in place. Next unscrew the graphite leaving the threads behind. Quote Link to comment Share on other sites More sharing options...
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