How to Cut Multi-Start Threads - Quick Machining Tips #23
ฝัง
- เผยแพร่เมื่อ 28 มิ.ย. 2024
- Here's a quick how-to for cutting multi-start threads, including using the threading dial, the compound, and the spindle gear. I also discuss how multi start threads are used in the real world.
If you like my videos, please consider supporting my channel on Patreon. You'll get access to gag reels and I'll give you a shout out in my videos.
/ stuartdeharo
Follow me on Instagram at / stuartdeharo
great tutorial on multistart sthreads. i had never seen the tech of using the thread dial. i learned something today. my first multistart was done between centers using a lathe dog and a faceplate. yes i'm old.
I'm going to have to watch tis several more times. It will click eventually. Thank You
Nice one Stuart 8-) there's also the tap method for internal threads i.e. grinding a tap to get clearance and then using it as a multi edge tool
absolutely well earned like, alltough i did hit the like button before i looked complete video to the end. Very valuable information in this video.
Interesting topic, would love to see more on the subject. Thanks for the look.
Very well explained and it was nice to see different way of achieving the same result. very good.
Very thorough. Thanks
Reminds me of a four start thread I was asked to do on a cup i was awarded. The silver cup and the bakelite base were held together by a quick start thread for easy removal of the silver band with the names on the recipients and over the years it had worn out. I'm pretty sure they only awarded the cup to me so i could fix it, but a win is a win.😉
Thinking of multistarters, have you seen the work of a young Russian (?) TH-camr who makes multi start left and right hand on the one shaft and matching nuts that turns both ways as it falls down the upright shaft? Somewhat amazing work!
I have seen that. Pretty cool stuff.
@@StuartdeHaro I wonder how many attempts it took?
@@chrisstephens6673
I think we are going to find out soon🙂
@@rickpalechuk4411 If he was like me the failures never see the light of day again. What? Me fail, never!😉
Great demonstration video clear on all the methods. When I get into that difficulty of measuring low thread counts with large spaces between the wires with a standard mic I revert to a digital calliper for measuring over the wires. It works very well providing the calliper jaws can be placed in line with the shaft axis and measured at the maximum crown height.
This single wire method is also covered by Joe Pie and works very well.
Educative and a good reference. highlight on the depth of cut of the tool and preferable rule of thumb applicable.
Hi Emijo. In this case, I cut my single start thread first so I had a baseline. That let me dial in my measurements on something easier to measure. Then I just cut the multi start threads to the same depth, making sure to measure as I got close to check for tool wear.
This is a great opportunity for learning 👌
Well, while you're screwing around with threads you might as well do one of those fancy/smancy forward and reverse threads that all the cool kids rave about :)
Cheers
VERY informative! I have long way to go before I try even single point threading - let alone two or three
I did expect a mention of the lead with multi start threads. Although the pitch remains the same between the threads, the lead increases by multiplying the number of starts. For example, a 3 start thread with a 2mm pitch would have a lead of 6mm. This is the amount the nut moves per revolution and the pitch that the lathe needs to be set at. An explanation of the difference between lead and pitch would have been very useful.
Very useful Stuart. I understood the gear method and the dti method, but I did not understand the threading dial method. The threading dial had 4 numbers and 4 half marks right (?) so how does 13/24 come into it? I guess it will come to me when I've thought about it enough. I have a metric lathe so more research is required on that too. But to cut imperial multi start it will have to be the dial or gear method. Cheers
Excellent video 😀 your a great teacher 👍
Educative and a good reference. highlight on the depth of cut of the tool and preferable rule of thumb applicabl
Very clear explanation. Wonderfully done.
Thank you my good man!
Thank you. I really find these tips helpful. 👍👍😎👍👍
Very good explanation. Respect!
Thanks! I was always wondering how those threads were made.
Awesome thanks for sharing
Very well explained......
Thanks for the tips.
You're very welcome. Thanks for watching!
Great video, as always Stuart. Being lazy, I cut a 3start thread by just rotating the D1-3 chuck to the next hole position on the spindle. Yes, that only works for a 3start thread but I got a good fit on an internal/ external thread, and I leave it on my mantle for those with interest.
A big regret about this video is not mentioning driving the part with a lathe dog and indexing off the chuck jaws. I don't know why it slipped my mind. I like your idea too. Same basic principle.
@@StuartdeHaro Good point on using the jaws on a 3jaw chuck to drive a feed dog. I guess by extension one could use a 4 jaw chuck to cut 2or4 start threads. I’ve seen some gallon milk jugs with a 12 start thread - don’t need to twist that cap much!
@@StuartdeHaro How would you make the female mating part.
@@billshiff2060 The same way except you would have to have an internal threading boring bar. I would make the male part first and then make the female to fit.
@@StuartdeHaro Cut a multi start female thread driven by a lathe dog? I'm not seeing it.
Between centers?
I worked for Southern Machine and Supply in my early 20's. I rebuild used machinery and so I threaded new lead screw nuts for the worn out nuts that were in all of them. Because all are made of brass the lead screw's were usually good and didn't need replacement. I would remove the lead screw's from the machines and custom cut the nuts for each lead screw so there was no more than 3 thousands of an inch play between the nut and screw. All of them were acme threads except for an antique lathe I rebuilt that was going to be used in a museum. It had square threads. I had to hand grind a threading tool for them that was slightly narrower than the thread width. I cut both threads to depth and then with the compound set at 90 degrees I removed 2 thousands of an inch alternating threads and checking the lead screw's for fit each time. It was time consuming but the rebuild budget for that machine allowed for it. When the Museum Director came to inspect the lathe he couldn't believe the back play was only one thousands of an inch on both the cross feed and compound dials. I got a nice bonus in addition to my regular pay for that job.
That sounds amazing! I would love to do something like that.
@@StuartdeHaro Not long after that I quit working for the Owner. He had not given me a pay raise in two years. I also wanted to go to college. I enlisted in the US Navy which has a college at sea program. I chose to major in Marine Engineering because the Navy would pay all the costs for that because that's where Engineering Officer's come from. I finished that but the Army recruited me for it's M1 Abrams tank program at the Anniston Army Depot. I was a Gas Turbine Systems tech in the Navy. The Army was having difficulty with people that had only worked on aircraft jet engines which is like apple's and oranges compared to the automotive gas Turbine engine in the Abrams tank. I spent the next 24 years as a Warrant Officer in the National Guard in the Abrams tank program retiring after 30 years service. Then I started working for myself lol. I had purchased a lathe and Mill from my Boss while I worked for him at his cost. I still have and use them for my motorcycle addiction creating custom parts and refurbishing antique motorcycle parts.
@@n4zou You may very well be the coolest person I've ever talked to.
VERY VERY NICE AIDEYA
I got excited when I saw your calculator: my first thought was RPN! Then I remembered my calculator was a 32s, the 22s was not rpn. That’s ok though .I will not hold it against you. ;)
You know, I have absolutely NO idea where I got that calculator. None. It seems like I've just always had it.
The other day I threaded a piece of brass right hand, left hand with double starts both ways. I also made a nut right and left double start both ways. I threaded the nut with right hand double start thread first and it screwed on my piece really nice, but when I threaded it left hand double start I couldn’t get it to thread on in either direction. I’m still thinking about that one.
Perhaps it's a tool wear issue?
use a gauge block to bridge the gap and then subtract it after
Great 👍
A person can do even more than just a comparison using the one wire method => M = (M1wire - 0.5D) x 2
Joe Pieczynski covered this in one of his videos and this is the method I've been using ever since for all my thread measuring.
Great video and thank you. My question is how do you get the total depth of the thread from machine book. Is it the major max diameter minus the minor diameter? I understand that by taking the micrometer and measuring the top of wires then subtract the cost from the wire sheet to get your final basic pitch diameter. Thanks and God bless.
This is great, I did like to try the compound method. Is there a formula using pitch and number of starts to calculate how much you need to mover over?
Your example, wanted 1 mm pitch, 3 starts = 3mm pitch for each starts. So 'offsett' would be start 1: 0, start 2: +1, start 3 + 2. Which means pitch per start = number of starts * wanted pitch. 'Offset' = pitch per start / number of starts.
I am just trying to understand this technique, Ive never cut a multi start thread before and I did like to try it.
You only need the pitch. The number of starts is irrelevant. Just cut one thread to completion, move over the amount of the pitch, cut to completion again. Lather, rinse, repeat for any additional starts.
@@StuartdeHaro Thanks
@@StuartdeHaro Thanks, it worked
Good informative video Stewart, I think the only time I've done a multi start would have been in tech an embarrassingly long time ago...
My Colchester T2000 has a thread chaser with a number of cogs with different teeth counts.
Ido have the manual and could look up the info but...
If you have a tutorial..
Metric as well.
Hi Carl. I'm not familiar with that particular Colchester (seems like there were 1,000 different models of them). My lathe at home isn't really metric conducive without changing a bunch of gears and fixing my inability to run in reverse. I can't film long videos at work either, but I'll try to come up with something.
How we can identify the multistart thread without seeing it's ends and without even touching it physically?
On my Lathe when I split a thread I just Rotate my chuck If you have a Cam Lock Chuck you can much easier
That's a pretty good idea. You can also do it by turning between centers and driving the lathe dog off the chuck jaws.
Can you cut triple start threads using just the dial indicator instead of the compound slide?
I don't think so, unless you find a gear setting that would let you cross thread in 3 spots. You can easily cut three starts by turning between centers and using your 3 jaw chuck to drive the lathe dog. Number your jaws 1, 2, and 3, then cut a thread with the lathe dog against each one of the jaws. You'll still need to have the gearing set to something divisible by 3.
What does the indicator table mean by the 13/24 that is next to some TPI values?
I had to rewatch the video to see what you were asking, but I've got it. That is stating that you can cut the threads by engaging at either the 1 and 3, or the 2 and 4, but once you choose either odd or even you have to stick to that choice. That's why you can cut 4 starts using the gearing for 6TPI. One each at the even and odd numbers on t the thread dial, and one each at their corresponding half marks. Let me know if that still needs clarification. Thanks for watching!
@@StuartdeHaro ah yes it’s so simple now that you’ve explained it. My lathe has the same table and I could never work out what that meant. Thank you very much. P.s. you should do a video on knurling (I don’t think you have)
Great video. I don’t understand it. Keep up the good work.
Is there anything I can clarify for you? I'm already planning a follow-up video, so I can try to show it differently if it will help.
No I dont think so. This is just a Little over my head. Thanks for asking and keep up the good work.
My lathe have up to 4 TPI setting, and i want 4 tpi double start, how to do it? Any idea.?
You need to have the lathe cutting 2 TPI for a double start 4 TPI screw. If 4 is the coarsest thread option for you, then you'll need to change the gearing on the lathe, which may be easier said than done. On the end of the headstock, you should be able to open a cover revealing the gearing between the spindle and the gearbox. That is what times everything together. You need to be able to double the speed of the gearbox in order to get 2 TPI. Of course, you may not have any spare gears for the machine, commercially available gears probably don't fit the shafts which are often splined, or you may not have room for the necessary gears, but if you can find a way to do it then that will solve your problem. Thanks for the great question!
@@StuartdeHaro ok, thanks for hear to me,, i tried by changing the rider to pinion, and pinion to rider, i go nearby, but not accurate,, i will try with different gears from market..
Thank again for knowledge..
38mm dia 6tpi
2 start thread I need
How to devait starting thread please explain
Like I said in the video, to cut a double start 6TPI, you'll need the lathe geared to 3TPI. Then just cut the thread to the 6TPI specification. Your 38mm diameter is incredibly close to 1.5 inches, so I'm guessing the specs for a 1-1/2 - 6 thread is what you want to look for. The range for major diameter is 1.4976" to 1.4794". Pitch diameter should be between 1.3893" and 1.3812. Lastly, your minor diameter is 1.2931, meaning all chamfers and thread reliefs are smaller than that. These are all specifications for the external thread. I hope this helps.
What the pitch as sir if triple
It doesn't need to be one particular pitch. Your gearing would just need to be set to 3x your desired pitch. For instance, if you want 1mm pitch for your threads, your gearbox would need to be set to cut 3mm pitch threads instead, 1mm for each start. In imperial, you would need to choose a TPI that is divisible by 3, for instance 12 TPI. Then the gearbox can be set for for 1/3 of that or 4 TPI.
13:15 show the math?
There's no math to it. You're comparing the measurement you get from your known good thread to the thread you're cutting. You have to make sure to remove any burrs first and make sure your major diameter is the same.
@@StuartdeHaro What if you don't have reference bolt? I need a 7/8"-20 bolt for a weld positioner that I'm building.
@@publicprofile1 You can just make your own based on the specs. That’s what I did with the single start thread. For 7/8-20 your major diameter range is .8737-.8656, pitch diameter is .8412-.8368, minor diameter is .8142.