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Telescoping Jack Screw - FINAL PROJECT

jlsmithseven

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#62
OK

And for the cap, I turn down a bar to .69, then how do the .19 radius?
 
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mikey

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#63
First, have you spoken to your instructor to try and clear up these questions? If not, then it might be a good time to do so because I am not aware of a ball nosed cutter sized to cut a 0.19 degree radius. Maybe he intends the hole to be bored or drilled to a depth of 0.34"?

To machine the hex, you have to turn your OD down to 1.0046", then cut the flats so the span from flat to flat is 0.87". See this calculator: http://janproducts.com/Distance_across_corners.html

Then you need to turn the end of the work above the hex to a length of 0.530". Then you need to ask the instructor how deep to cut the 0.150" wide relief cut (under the ball) because it isn't called out and we can't infer it with the info in the drawing.

Then you need to file the radius on the end of the ball.

Then you need to make the cap. I'm not sure how he wants it done. I would leave the work long, lock it in a collet block, angle the block to 45 degrees and support the block with a jack or some other support to prevent movement. Then I would cut the V with an end mill. Once the V is cut, part it to length and drill or bore the hole for the ball.

I think there is enough uncertainty here to warrant a discussion with your instructor to clarify the above points.
 
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MikeWi

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#64
+1 to the above. Your teacher should be able to tell you everything you need to know in order to finish this project, or he's not doing his job. I'm not saying you shouldn't ask for help here, but it concerns me that you have to.
 

francist

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#68
Typically for adding support to parts as they're being machined. I have one though that I find really useful as a jaw spreader when cutting short lengths on the bandsaw (stops the vise jaws from going cock-eyed). The telescoping ones give larger range in a small package. The setup below isn't mine but it gets the idea across I think.

-frank

image.jpeg
 

David S

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#69
Holy crap that is one helluva set up there. Just about every aid one could think of.

David
 

francist

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#70
Yes, and perhaps the photographer was standing on a milk crate when he took the picture too....

(Like I said, not my setup! :)

-frank
 

jlsmithseven

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#71
Yep, basically just like that. We are making two because if you have a really long bar and want to cut both sides maybe, you will have support on both sides. The nice thing about mine is that the 45 degree slot at the top of the caps allows me to clamp round bar in the vise as well.
 

terrywerm

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#72
Justin, the work you have done is looking pretty good, despite some of the problems you have run into. Don't forget that making mistakes is part of learning, and it's best to make them sooner than later.

Did you remove the drawings for this project? I noticed that they are gone from the initial post in this thread.
 

mikey

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#74
Outstanding! So, Justin, spill it - did you pretty much get full credit for this?

If you approach your internship with the excitement and open mind that you've displayed here, you'll do great. Good luck!
 

Rustrp

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#76
Well it hasn't been graded yet, but I think it's an A-. Thanks for the tips, I definitely will approach my internship with a positive attitude.
I know there were a few changes but I was looking forward to the crimping operation for the cap. Was this a change also?
 

jlsmithseven

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#77
Not sure. The .19 radius was changed to a .250 radius so just used a .250 endmill to make little cuts on the end. Still has to grade the top so I can't crimp it in yet.
 

Silverbullet

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#78
If you were advanced a bit you could cut a groove in the cap and use a o ring to keep the cap on instead of peening it on. After awhile you will be able to look at things and in your mind figure alternative ways of doing things. Or problem solving I call it. Think and do.
 
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T Bredehoft

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#79
After awhile you will be able to look at things and in your mind figure alternative ways of doing things. Or problem solving I call it. Think and do.
I find that I can sometimes "solve the problem" while trying to go to sleep at night. The mind is free to wander and often I'll stumble over an easier way to do something. Then, the next day, try to remember the solution, and what problem it went to.