Machinists.....Tapping a thread on a Mill or Lathe?...Don't Do This !!!
2024 ж. 16 Сәу.
51 235 Рет қаралды
Just because a 'T' handle drives a tap, it doesn't mean it's giving you the best thread or security possible. This short video clearly illustrates the 'T' style handle may not be your best choice for smaller diameter threads when used a certain way. You really should watch this if you're new to machining, or experienced and really curious. Thanks.
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I am an enthusiastic hobby machinist. I've never had the benefit of personal instruction in the machine shop. Everything I know about machining comes from KZhead, books, magazines and similar sources. Of course experience is the world's best (and sometimes harshest) teacher. I certainly didn't know what I didn't know on this one. Luckily, at least some of the KZhead creators are true experts, with you being a prime example. Thank you so much for this, and all your efforts to put a dent in my ignorance.
You say how I feel also, with such style. Thanks!! I agree with you!
Yup! I agree. I had NO IDEA a tap T handle was not made ‘true’. Great tip.
👍 ! Great tip , surprised that this never occurred to me before, and surprised that I haven’t broken a lot of taps over the years.
The wobble of the tap as shown was more a result of a bad chuck in the tap holder than the hole at the back of the handle.
That's what it looked like to me, too. It looked like a banana, more wiggle in the middle than back at the end. If the misalignment was caused by a lack of a positive centre at the rear of the tap handle, that's where there should have been the most movement? It also seems like something that could be more easily shown by chucking the tap handle into the lathe and reading off the runout of the OD vs ID...? Disclaimer: absolutely *not* a machinist, but I reckon I can troubleshoot and interpret stuff pretty logically. The logic he's describing doesn't seem to match the results he's displaying here. Disclaimer on the disclaimer: It seems like it'd be a pretty good idea to validate your tap follower and not just assume it has a precise centre, just on principle. That's absolutely a good point he's raising.
Been using a tap handle for 40 years! Yep been doing it wrong too! Thanks for the education!
I don't think I've ever had my mind forcibly changed so quickly. You succeeded at this in only 10 minutes and 39 seconds. Congratulations Joe.
Damn it Joe ! I been doing this for years > down to #4-40 > haven't seemed to have a problem. But ur demo valid > shocked to see the tap run out that bad . Ya got me thinking. BTW, you & Mr Pete > best vids here on machine work
Balderdash!
Absolutely right! However, it's not the center, it's the jaws. We (retired from GTD) machine the entire body, including the center. At this point everything is concentric. The second OP is to drill, then saw the front to create the jaws. This is where the concentricity breaks down. The next OP is to spring temper the jaws, which causes the jaws go out of whack. This is where the real issue occurs. In theory, the cap is supposed to bring everything back into alignment. However, between the burrs from the saw cuts, and the slop between the threads in the cap and body, it doesn't allow the cap to pull everything back into alignment. Some brands are better than others, but as you state, bad idea!
Yeah na. I'd go for lil ER 11 Collets and turn it in one go, head upside down, parting last. Almost. Dunno yet. It's late lol. But that's the inspiration I got from this.
I haf no idea my spring followers were reversable until this video. Thanks for sharing your knowledge and experience.
I've been using those T-handles for over 40 years and never thought about the handle being off that much. Thanks for the clearly demonstrated proof.
It just goes to show no matter how old you are we are always learning, that’s something I didn’t know thanks
I'm glad you used non-magnetic aluminum! It doesn't look like people picked up on that!
Still puzzeled about the use of the plastic flim on the demagentizer. Never used it on mine! Lol.
Well, well teach. I have never used the lathe as a tap driver. A tap held in the tailstock held by a drill chuck, yes. I have seen the physical dammage caused by power tapping has removed and dammaged man a hand so I just don't do it. The time saved isn't enough to worry about. Starting a tap, the right long taper to start and a gentle touch for me works just fine. I am a patient fellow by nature, I have always thought machinists were all like that are we not, LOL. Over the 45+ years of machining I can count on my hands how many taps I have broken and they we ALWAYS from alighnment issues. Keep em straight and be patient and enjoy the thing we love to do best. Thanks a bunch Texas. Great post and a bit of schooling today too. Thanks eh.
I like your friend' saying: "It's impossible to know what you don't know" - that keeps us learning all the time without challenging the ego.
I'm one of those guys who didn't now about reversing the pointer on the tapguide. Thanks again, I always learn something watching you stuff
I didn't either
Great to hear!
Every time I watch one of your videos I learn something new. Thank you for sharing your knowledge.
I've been a maintenance machinist/mechanic for 40 years, and I have never used a T handle tap wrench in a lathe or mill. It never even occurred to me. Just put a drill chuck in the tailstock / spindle, grab the tap hand tight, and send it in at low speed. I have tapped hundreds if not thousands of holes using this method and I've NEVER broken a tap. I can hear the hate coming already. "4 flute taps are hand taps!" Yes. You can use this method to get them started, then switch to a dead center to support the tap and use a tap wrench (NOT T handle) to finish. Or if the tap is large enough, I just use an adjustable wrench. As long as the center is in the guide hole at the back of the tap, you're good. "Gun taps will fill the bottom of the hole with chips!" Also true. But you can back it out and clean out the chips if the hole isn't deep enough. I've used this method down to #4-40. Never had a problem.
Only problem is taps are hard and it slowly destroys drill chuck jaws.Collets are much better for holding taps.Most of the time i just spin the spindle or lathe chuck by hand (tailstock must be free ,not locked down).Its good enough for start Not a cnc speed of taping but it gets job done.
I used to just use the drill chuck to hold the tap. Then turn the lathe chuck by hand just to get it started straight a few threads, then finish by hand or with small threads just leave the tailstock unlocked and turn the lathe chuck by hand.
Things you don't learn at school... Thanks Joe.
Interesting video and you made some very good points but the biggest point you made is that most tap handles are junk. Actually all tap handle to some degree are junk... just a bad design. With this being said, unless you are using a tap under a 6-32 tap the likelihood of breaking a tap is very slim and to a very large degree the tap will align itself. You can verify this by tapping with a wobbly handle, remove the wrench and turn the lathe on. The wobble will be very minimal. I have broke my fair share of taps but so far I have never broken one that is guided from the back of the handle unless the handle slip out of the guide. I made a tap wrench with a tube on the back that slips over a 3/8 countersink to eliminate this problem.
Thanks for the advice Joe. I'll no longer do that anymore. I normally start the tap in the drill chuck and feed in into the part to get it started, then finish off with a T handle wrench, sprung loaded. I'll be careful what I'm doing from now on. I, like some of the other comments on here have tought myself how to machine parts so I'm loving your channel and the advice you give out. It is appreciated.
Thanks Joe! I observed this phenomenon when tapping on my old drill press and blamed the drill press. After that I bought a hand tapping machine and never went back to using a tap guide in the drill press-even when I bought a new one. On my lathe I just used the drill chuck in the tail stock to start it then switched to a tap handle to finish.
You're right about the centers being off, but it's sometimes on cheap wrenches, the jaw faces are not square. I made my own, and used them with centers in lathes, vertical mills, radial arm drills, for more than 60 years, and produced nice, square holes, every time. A long time ago, I started hating tapping, without a lail support.
Outstanding video. One should never assume the precision of tooling, without testing. Been there done that. Charlie
I definitely noticed that runout, even on a Starrett tap handle. Great video, thanks
Absolutely agree! I ruined a small valve body for a high-pressure Ingersoll Rand compressor that took me 6 hours to machine " Im just a beginner " because i used a T handle that was a mile off. The center screw threads were off angle, and I couldn't figure out what I was doing wrong. My old machinists friend set me straight. And greatings from McMurdo Station Antarctica. Home Houston Texas 😊
... and for the really small taps, use one of Joe's small knurled disk tap drivers between thumb and forefinger. Life savers!
Totally agree, but lots of my taps don't have a conical point or a conical centre. I suppose I could grind a male centre on the end though. I've always blamed the split jaws on the tee tap handles. They are rarely the same dimension as the square on the end of the tap, so they pinch just on one end or the other. Regards, Preso
Agree 100% Mark 👍 Robert
I made a lot of small stuff in my day, and used a lot of small taps. Broke quite a few and at some point noticed this same problem. It's much worse on tap handles labeled "General" than on ones from Starrett or other quality brands. I noticed another thing too. Take that tap handle apart. Look inside the part that is like a collet. Notice that it has more than four flats. Four at the tip and then four more further inside. Place the tap far enough inside that the inner four flats drive it and the outer four flats bear on the cylindrical part of the shank. Note how much more concentric it runs. This is only for taps that fit up inside like that but it definitely helps. Also, you can remake the main body of a cheap tap wrench much better if you chuck it in a four jaw and redo the "center" that it has for the tap guide to run in. Thanks Joe!
Thanks so much for this !! those pointed tap ends WERE the bane of my existence - I had no idea that was reversible
Joe, great video as always. I do a lot of threading with small sized taps for astronomical telescopes, mounts, and cameras so breaking one is always a risk and can be disastrous. One thing many don't realize is taps come in different types. The standard most common type has a taper to the thread cutters so it can be aligned somewhat as you start the operation. There are also bottom threading types that are designed to thread far down into a blind hole (one that doesn't go completely through the material) They have very minimal starting taper.You NEVER should start with that one. The other type has a much longer taper to help perfectly align the tap and those are the one you should start with to ensure your tap is perfectly aligned with the hole especially on small tap sizes. I buy my taps in the sets that include all three types for each thread size. I am now 77 years old but learned this from my teacher in a gunsmithing class 60 years ago. I had spent hours machining a bench rest rifle barrel and action that was blued and only thing left was to drill and tap for the scope mount. I was terrified all that work would be destroyed with a broken small tap. My instructor showed me his tricks and it was completed perfectly. The most critical thing is the start of the tapping operation... make sure the hole and tap are absolutely aligned. Also take the time to back the tap out several times to clean out all the bits of metal cuttings. It is tempting to get lazy and try to power the tap through when it gets a bit tight due to chip jamming. That is when things go south
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The Starrett chuck type (T handle) tap holders are beautifully made and have a separate, spring-loaded jaw assembly. (Similar to the chuck in an old woodworking brace.) This gives them a large size range and a good grip in my experience. However it is the source of their run-out. The chuck type tap holders that used to be made by Eclipse (James Neill) and Moore and Wright in the UK have a cheaper construction where the body of the holder itself is split to form a collet. This limits the size range of each holder and I don't feel they grip the square on the tap quite as firmly as the Starrett type, but it does eliminate the run-out you illustrated so well. Another point is that some taps don't have a centre hole or a cone at the square end. (I guess you could modify these by hard turning or grinding your own cone on them.) Thanks for the advanced insights and tips that no-one else has seemed to come up with.
I was going to say (before Joe kind of pointed it out) that the concentricity error is not (necessarily) in the centre at the end of the T-handle but where the chuck holds the tap. I've got some beautifully made (looks wise) chucking T-handle chucks and literally nothing is concentric with anything....so at least Starrett get more points than those!
Every day is a school day. I never knew the spring centre was reversible.
I'm glad others are learning this. I have tried to explain this to others, and without real time to explain in the shop atmosphere do to production it was difficult. It's amazing how some tools aren't applied correctly. Thanks to Joe Pie it's now out in the world. I learned this the hard way messing up on a part. Also a tapping block is a good thing to make to get the tap started.
I am not a machinist - but I am a hobbyist who's been making parts for many years. I've never seen this addressed before. Thank you!
And my learning continues. Never even thought about it before. Thx Joe!
Nothing beats a good visual demo - point well made Joe!! :)
THANK YOU! After getting away with this for many years, you have shown me the light and the error of my ways. I had no idea that there was a second end on the spring loaded tap guide.
Thank you Joe. Sometimes a demonstration proves a point. I will stop the practice that you just condemned! I am a new believer.
Maybe my 40 year old T handle is one of the good ones. I have been doing this for 40 years and never had a problem.
A picture is worth a thousand words. Beautifully presented. Thank you!
Excellent demonstration Joe.
Make all of your own tools, if you want precision. Remember that you can only be as precise, as the least precision piece, you are working with, and tolerances, stack up.
Brilliant demo. 👍
Joe Pie, never disappoints, or fails to educate!! Kudos Joe!!
Great tips as ever, Joe you are a master of showing us those things that we just about did know, but not quite.
You are so full of it Joe. "It" being valuable information learned over a lifetime of experience. Thank you very much for taking the time and putting in the effort to share such knowledge with the rest of us. I truly appreciate it!
Joe this was a great example of how you don't realize how you can build tolerance into a part and think your doing a good job, seeing is believing.
As always thank goodness you are there to guide us
You got me. I have been using a tap handle like that and did not realize it was doing that. Thanks for showing me this.
Thanks for this video. I could see myself going crazy if I'd scrapped my work from it.
It removes a great deal of the risk.
Joe ~ I've been tapping a lot of small holes in expensive stainless parts. I can't count how many taps I've been breaking off in blind holes, ruining the parts. I've been using taps a couple sizes larger than the 75% thread recommendation to get around the problem, but it's still pretty scary. The info you shared I'm betting is 100% of my problem! I'll check it out today in the shop but this was a terrific bit of information! Thanks.
Excellent. Good luck. Another gem is not to over power the tap with a giant drive handle. The smaller the tap, the smaller the handle. You'll get much better feel.
Lol, idk why...but Jackie Gleeson kept coming to mind in Smokey and the Bandit. "You can think about it...but don't do it...." 😂
Thanks Joe. So clear and informative. Love your channel, so much insight and knowledge you are happy to share.
Hi Joe, thanks for that. Its pure workshop gold! Keep 'em coming.
Well explained and visualized. Thanks Joe
Thank you for a very informative video Joe.
Good stuff, Joe! Found this out the hard way years ago. Basically used the same methods you demonstrated to discover the runout of the different drivers. Thanks for your time and sharing! 👍😎✌️
Bravo Joe PIe, always spot on information, cheers from Florida, Paul
Excellent tip, I never knew that a T-handle would have so much runout. I also never knew that those tap followers had a concave end on them, I'll have to tear mine apart and see. Thanks, Joe.
Amazing! Thanks Joe, I never would have thought that.
tour expertise is excellent. My practise is now changed thanks to Joe P
I discovered that an ordinary but high-quality drill chuck holding the tap hand-tightened. Drill the hole, then switch out the drill for the tap in the chuck, then tighten the tap by hand. Spin it up, and when the tap binds in the hole, it's dead center. Loosen the chuck, and it can be finished by hand with a t-handle. It works 100%.
I always learn something useful from your videos...thanks.
That is cool. Your set up bypasses all the tolerance stack up compared to the "normal" set up. It's funny how in machining you can have process issues that you just kind of put up with for years, then someone shows you a fix and it's so simple! I think we get stuck in our ways. That is going in my bag of tricks, thanks!
Brilliant. Something new every time.
Thank you again for your simple and extremely useful tips!!
Good advice as always Joe...... Tap wrenches vary quite a bit..... I have a little "Eclipse" one that I have owned for over 50 years and it runs true to less than .002", but the others I have are not that accurate. I must make a tap follower..... I often use a tailstock centre to start a tap, turning by hand and keeping the pressure on with the hand wheel at the same time. It works, but needs care, so a decent tap follower is on my 'to do' list... 🙂
No wonder my threads are loose. I have always gone it this way. I did notice that it was not concentric but didn't think it mattered. I'm not a professional, just do what I personally need to do. And that's why I watch this pro. I learn something every time. Thanks Joe, I will change my ways.
Just put the tap in the tail stock chuck, close the jaws so that they are not tight enough to stop the tap rotating, and use your handle. I've been doing it that way for over 50 years. I don't break taps.
Once the tap is in the tailstock chuck, the square end is inaccessible. How do you drive it?
@@joepie221 You grip the shank or the end of the thread ( at the square end ) with the same screw on handle. I use a small 2 piece tap wrench that does the same job. On taps over 6mm/1/4" I grind a flat on the shank, because the handle/wrench tends to slip on that smooth shank, because of the torque required. So you only have as much shank as necessary for accuracy in the chuck jaws. Make my own miniature tap wrenches, and they tighten with 2 Allen screws. They grip REALLY tightly.
I really appreciate all you do and share, thank you so much Joe, Paul in Orlando
I can’t tell you how many times I pulled out a tap to use with that spring loaded tap guide only to find that it was pointy on the back end with no center hole and I had to tap freehand. I had no idea the end of the guide was reversible 🤦🏻♂️! I feel like such a doofus! 😂
No one who has learned something new is a doofus. A doofus is the person who watches this and keeps using the T-handle because they don't believe the facts in front of their eyes.
Love your stuff, joe. I've learned a lot from you over the years. I recommended your videos to the younger people in the shop. Thank You and please keep posting.
Awesome, thank you!
Wow. What a great. It's always a good idea to stick around to the very end.
Well, I won't be doing that again. Thanks, Joe..
It has always made me smile watching certain KZhead apprentices run a tap in this way while the tap spins off centre. For small taps I made and use something like your sensitive drilling setup. It's how a manual tapping fixture works anyway.
G’day Joe, how’re you doing? It’s always a delight to watch your content. Always learning something new.
We’ll shit! Every time I come back to this channel I leave what I know at the door. Thanks so much for pointing this out. I’ll be sharing this with a few friends.
Learned something new again. Thank you sir.
Made your point very nicely Joe, Thanks for the demo! J
As always another great shop gem.
As always, a great, informative video. Thanks.
Good information, when I worked in a tool room for an injection molding facility not one of the tool makers brought up that point. I figured it out on my own by striving to get better through techniques.
Great video, tip, & how-to, thanks Joe!
Good video Joe , I like these type of video from yourself a lot. Everything you said has been absorbed and understood Thanks for sharing
Glad you enjoyed it
Thanks for reminder, Still need to make the spring loaded tap guide. That small handle has been on my TO-DO list a long time.
Thanks for the tips ... just ordered a Fisher tap guide ...
Thanks for the great information Joe! Never even occurred to me!
I made a couple of these tapholders inspired from Your old video - they work great! For very small taps I use a shopmade contraption with a small chuck on a 150mm handle with a precise center. Dia is 15mm with knurling, works nicely for small stuff since it is possible to feel the small torque before messing up...
Thanks for the heads-up - I did not know this.
Great lesson Joe!
Good to know Joe I would not thought of that.
Thanks Joe, that was interesting to see.
If I keep on watching, you I might turn into a sort of machinist given enough time. Thanks for the video keep on keeping on.
Hi Harold. I always appreciate when you take the time to visit my channel. Thank you sir. Stay well.
Great tip Joe, thank you!
that a good tip joe, thanks ! cheers ben.
Thanks Joe! I had no idea.
Excelent tip, ur right, hours spent making a little piece and suddenly a tap snaps..... Greetings from Mexico
Thanks Joe! I have been enlightened! 👍
Good little pointer , thanks for sharing some of your well known experiences!
My pleasure!
okay, you have convinced me to make a tap follower and a similar style of tap holder since I regularly make M3 and M4 threads. I'll just copy what I saw here. thanks!
I learned something today! thanks Joe.