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Telescoping Jack Screw - FINAL PROJECT

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jlsmithseven

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#1
So, our semester is reaching its completion on May 10th. I have ONE final project I need to do and I'm going to need some help with it. It introduces some advanced Lathe techniques. We have to cut it all with HSS tools and 1018 CRS material.

I haven't started it yet, but please keep it in mind because I will probably be back to this thread if I run into problems. Have a glance and see what issues you think might arise. Thank you guys!!! I want to finish this semester out strong.
 
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mikey

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#2
Looks like a cool project, Justin. Basic lathe work - turning, grooving, knurling, internal and external threading. The only thing that might be interesting is the ball on the end of the small jack screw. It has to match the inside of the top piece? Do you have a radius tool available? From the dimensions, it looks like the top just perches on top of the top screw; it doesn't snap on, or does it?
 

terrywerm

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#3
According to the print, the cap fits onto the top of the small jack screw and is then crimped or swaged so that the cap is retained on the ball at the top of the screw. Look closely at the print for the cap and you will see that its recess is simply a drilled hole and is not rounded to fit the screw at all.

But, like Mike said, it should be a rather straight forward project. Think through the steps for each part, even writing them down so that you have a good plan to follow and you will do just fine.
 

mikey

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According to the print, the cap fits onto the top of the small jack screw and is then crimped or swaged so that the cap is retained on the ball at the top of the screw. Look closely at the print for the cap and you will see that its recess is simply a drilled hole and is not rounded to fit the screw at all.

But, like Mike said, it should be a rather straight forward project. Think through the steps for each part, even writing them down so that you have a good plan to follow and you will do just fine.
Teach me, Terry. Where does it say the cap is crimped or swaged?
 

terrywerm

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Teach me, Terry. Where does it say the cap is crimped or swaged?
It's on the top left print which shows the entire assembly, titled "TELESCOPE JACK". In the right center of the print, it says: "NOTE: Crimp Edge of Cap When Assembled."

It could probably be swaged with a punch and a hammer, or maybe a swaging tool for use in a press could be made just special for this project. Personally, I would just go the hammer and punch route as it should go pretty easy since only about 2/3 of the diameter will actually be available for swaging or crimping.
 

terrywerm

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#7
No problem, Mike, we've all been there - and more than once!
 

ddickey

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#8
Order of ops will be important. Using one part to hold the other. Looks very similar to the one I made copying from a crazy canuck. A Jack screw should be a fine thread imo which doesn't count for much. LOL
 

4gsr

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#9
I agree with ddickey, It needs to be fine threads instead of coarse threads. 1.000-14 UNF and .625-18 UNF. Some people may think 1.000-12 is correct, in my neck of the woods, it's 1.000-14 UNF. I would make the base a little larger diameter, too.
 

tomh

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#10
That lazy machinist did a 7 part? series on a jack like yours. He is a retired shop instructor, so watch his video as he shows the proper sequence of operations and assembly. This is a project he had his students build.:encourage:
 

jlsmithseven

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#11
Looks like a cool project, Justin. Basic lathe work - turning, grooving, knurling, internal and external threading. The only thing that might be interesting is the ball on the end of the small jack screw. It has to match the inside of the top piece? Do you have a radius tool available? From the dimensions, it looks like the top just perches on top of the top screw; it doesn't snap on, or does it?
I believe it snaps on, but I could be wrong. We haven't done internal threading yet, or radius cutting. We formed a radius with our file, but never cut it yet. This project introduces like 3-4 new concepts that we haven't learned yet and it's due in a month. I'll keep you updated. I'll be starting it next week most likely.
 

Uglydog

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#12
Am following closely as jacks are one of the projects on my to-do list.
The "Generals" I've got don't work as well as I'd like.

Daryl
MN
 

jlsmithseven

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#13
I'm starting the "SM Jack Screw" today. I got everything turned down to the right diameters and I am going to thread the ends next. BTW we have to make two of these, not sure if I mentioned that. So once I do one thing on one end, I just flip it and do it on the other. Got a lot more done than I thought I would today. Was taking .100 cuts at a 329 RPM and .003 feed rate. I think I will bump it up to a .006 feed rate for my roughing passes because my chips kept tangling up. Anyways, enjoy!

Note: The last few pictures are for Mikey to show him how well I can clean a machine when I'm done with it:). Thanks buddy.




 

Rustrp

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#14
I noticed in the second photo there was a padlock. That's how they keep you there. :D

Because machine tools and the processes interest me, I keep links to a few things that I probably will never have time to get back to or have time for. Your task of cutting the radius/ball challenged me to look for a link.

http://www.micro-machine-shop.com/ball_turner.htm

I'll be wating for the ball and swaging process. Nice work.
 

darkzero

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#16
Wow, just as clean as Darkzero's machines! Good job, Justin!!!
Oh crap, here we go again. I'm going to delete all those old pics of my clean new machines. Well no I'm not, I like looking at them!

Justin, those Leblond Regals look very similar to the Regals I used at my local CC. But the ones they had were servo shifts. I really liked using them. I miss the collet closers & I wish I had a huge pull out chip pan like them.

We were required to clean up the machines we used after each day. Most kids were lazy except my lil brother. I was just happy to be able to be there to use the machines. I don't miss cleaning up the big Cincinnati horizontal mill when using flood coolant. What a mess!

I thought about going back just for the heck of it but I stopped going when I completed the course & my instructor retired. I never knew our local CC had the machining course. My lil brother needed a technical credit so he took it for 1 semester. I was his ride to get to & from there so I figured I might as well take the class with him. Glad I did, it was a lot of fun. My brother only took 1 semester, I went for 3 or 4 I think, I forget.
 

jlsmithseven

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#17
Haha thanks. It feels good to arrive at a clean machine, I can't argue that....Lesson learned.
Yeah the leblond is easily my favorite lathe in the shop. It feels solid and cuts very nicely. I wish I had my own, it's a lot of fun.
 

darkzero

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#18
Just glad to see conventional machining courses still available. None of my high schools had machine shops. Most colleges are offering only CNC now.
 

Sleddog

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#19
Arrive at work fresh & ready to start your shift & the machines are a mess is akin to walking into the bathroom & un-flushed toilet!

Our high schools offered vocational machine shop for junior & senior students. Three area Vo-tech schools offered classes too. None of them offer any type of machining training now. :apologize:
 

jlsmithseven

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#20
Some footage of me taking .100 cuts at a .003 feed rate. My friend said he ran a .012 feed rate while taking .100 cuts, but I thought that was too quick for that much material...?

 

Silverbullet

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#21
I remember those days in vokie, there nothing like getting out in the real world. You don't just watch your machine run , do your deburring. Clean up . At least when I started , still remember the worse job I had in any shop. Cleaning the sump on a big turret LATHE using your hands to scrap the foulest smelling crap out. That had to be done about twice a year on every lathe with water soluble oil. Sure don't miss that. But back to your project , I agree with the fine threads , but if your being graded I'd stick with the print , unless you get a revision on it . The Jack looks like it will be usefull , do yourself a favor make two. You will find many times over your need for more then just one. I think it may be good to add for yourself some knurled nuts to lock one section. Just my observation.
I'd make them for both myself. The 1" and the 5/8" threaded as each section.
 

Silverbullet

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#23
so what you're saying is my first job will be cleaning machines?
No I didn't say that, I said you usually are asked to do more then just watch a lathe run . May be different now but when I started I had to do more things besides run a lathe or mill. While it did it's job I had to deburr ones that were done , or keep ahead of the chips by cleaning them out . Read the post don't jump to conclusions no one's attacking you. Just things I've been through. Has far as the cleaning of the sumps it was part of working on the machines . They didn't clean themselves . And they didn't hire cleaning people . Just part of the job
 

Rustrp

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#24
Arrive at work fresh & ready to start your shift & the machines are a mess is akin to walking into the bathroom & un-flushed toilet!

Our high schools offered vocational machine shop for junior & senior students. Three area Vo-tech schools offered classes too. None of them offer any type of machining training now. :apologize:
Unfortunately, vocational programs are at the mercy of academia. Has anyone ever heard of anyone teaching a STEM class justifying the funding for their classs based on the number of students placed in a job/occupation based on their study? How many high school football programs have been shut down due to budgets? I know this isn't true across America, but when a school district reinstates a vocational program it's promoted as if someone had an epiphany, vocational training is a path to jobs and an improved economy, WOW!

Okay, soapbox put away. :D
 

Rustrp

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#25
so what you're saying is my first job will be cleaning machines?
There are few cars on the road in good condition, where the owner didn't take of it. If your first job was cleaning machines would it be bad. If you had to clean machines that were supposed to be cleaned by the operator and they didn't, I'm sure you wouldn't be a happy camper. Otherwise the amount of cleaning you experience will be part of the job as long as you choose to machine, and it should be.

If the cleaning is delegated to someone other than yourself how do you or will you know the condition of the machine you're running? Let's say you have a run of 500 parts to get done today and the cleaning of the machine is delegated to the apprentice and he's not happy cleaning nor understands why he must. So the fact that the chip auger had been getting sloppier for the last two weeks isn't a big deal to him, but it is to you and at 235 parts into your shift things fall apart. Maybe you would have seen the failure coming and a little preventive maintenance would have prevented the shutdown. The maintenance crew could have repaired the auger on the night shift...........?
 

TakeDeadAim

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Some footage of me taking .100 cuts at a .003 feed rate. My friend said he ran a .012 feed rate while taking .100 cuts, but I thought that was too quick for that much material...?

Your chips are not blue and the finish looks reasonable so you could up the feed. RPM looks slow for Coll Rolled. 100x4 divided by the diameter should get you in the speed. Grab the closest you can get on the LeBlond; those lathes are pretty rigid.
 

jlsmithseven

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#27
Sorry SilverBullet if I came across that way, just trying to get first-hand info of what its gonna be like at an actual shop because I've never worked in one before!
 

jlsmithseven

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#28
Hmm, I was told to take 280 / workpiece diameter. That gave me 280 and I put 329 on the Le Blond. I usually run it at 436, but slowed it down some based on the calculation. The finish was actually pretty awesome, so I could have easily gone double the speed, at least for roughing I think. You said .100 x 4 / diameter and that gave me .001. Did you mean 100 x 4 / diameter, that gave me 400, which is similar to what I usually ran at...
 

astjp2

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Well the place I work at hired 2 people to clean machines and change coolant, made the operators lazy! I usually get the "well its been hammering for a week or so" or "its not working" when I find the 1" end-mill chunk that broke off laying in the auger and they have that deer in the headlights look and say it was the other shift. My favorite was finding a 321 block in our chip puck maker, made it through 3 different augers before stopping up the feed auger just before it was about to get munched by the 60 ton ram...but no one knew who was missing a 321 block?
 

TakeDeadAim

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Hmm, I was told to take 280 / workpiece diameter. That gave me 280 and I put 329 on the Le Blond. I usually run it at 436, but slowed it down some based on the calculation. The finish was actually pretty awesome, so I could have easily gone double the speed, at least for roughing I think. You said .100 x 4 / diameter and that gave me .001. Did you mean 100 x 4 / diameter, that gave me 400, which is similar to what I usually ran at...
I think you saw the period at the end of my sentence and read it at ".100. The universal formula for calculating speed, be it turning, boring, drilling or milling is Cutting Speed x 4 / diameter

So for 1018 or mild steel the cutting speed is generally listed at 90-100; so 100 x 4 = 400/diameter

Cutting speeds for common materials are listed in books like the Machinery's Handbook, South Bend How to Run a Lathe and in many places on the internet.
This site just happens to be one I have printed the chart from because it fits on one page.
https://www.wisc-online.com/LearningContent/mtl8202/MLT8202.htm
 
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