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aboard_epsilon
06-23-2005, 06:21 PM
Who can come up with the best design of these.
sketches,ideas welcome in this thread.
all the best.mark

mochinist
06-23-2005, 07:25 PM
Such a handy little tool, everyone should have atleast a couple in their toolbox. I don't have the plans for the set I made back in school anymore but I found a link to some pretty nice one's that most anybody on this board is probably capable of making. The only thing I might add to these is a V-groove in the top for jacking up roundstock. You could also scale these up or down per your need.
http://www.davehylands.com/Machinist/Projects/Machinist-Jack/index.html

http://members.shaw.ca/dave-hylands/Machinist/Projects/Machinist-Jack/Thumb/08-Oil-Finish-Closeup.jpg

aboard_epsilon
06-24-2005, 11:53 AM
Thanks Machinist..that's the design I've seen all over.
I was maybe thinking of a sort of t-nut design.....so it has that top half in the design you suplied and maybe t-nut in its lower half to fit into table of a milling machine .
does this idea sound ok..or do you think it has drawbacks
all the best..mark

Gary Rose
06-24-2005, 01:06 PM
OK, this is probably a pretty stupid question - but so be it. What would these be used for?

I have a pair (still in the original packaging) that I've never seen a need for. I've always been able to use a vise or clamp the work to the table. Any particular application that these are valuable for?

A friend of mine is a journeyman machinist and told me that they have pretty limited uses and I would probably never need mine. So far he's right.

Gary

tattoomike68
06-24-2005, 01:09 PM
here is one I made about 14 years ago in college. I dont have the print though. I still have 4 that I made. as you can see they get used.
on tall funky parts you use the jack to hold them up so you can clamp them down, you cant just clamp a part with air under it.

http://img.photobucket.com/albums/v488/miketattoo68/screwjack.jpg

[This message has been edited by tattoomike68 (edited 06-24-2005).]

Your Old Dog
06-24-2005, 01:26 PM
I need to make a set for milling slots in 5/16 inch stock. It's a lot easier on the table http://bbs.homeshopmachinist.net//biggrin.gif I like tattoomikes design as I think it would be easier to reach in with a small shaft as opposed to a wrench.

[This message has been edited by Your Old Dog (edited 06-24-2005).]

aboard_epsilon
06-24-2005, 01:27 PM
Gary they are used,if your say; surfacing an iregular shaped object,that will not lie flat on the table of a milling machine.
you would chock it up best as you could with parallels and then mount a clock on your machine so that you can clock the part, so that you get it near true all over the surface .
Then the jacks come in to there own... to finally tweak it till the clock reads almost zero as it passes over the surface.this is done as you wind the table to all areas where the workpeice will be as it's machined.
they also can be used for other jobs were you are cutting tapers on things ect.
you would have to use them in conjuction with a pertractor/bevel on some jobs.
think of them as four jaw chuck for milling
all the best....mark

dp
06-24-2005, 02:31 PM
Best I've seen are here:
http://homepage3.nifty.com/amigos/screw_jack/screw_jack-e.htm

Plenty of great stuff on this guy's site.

dp

coles-webb
06-24-2005, 03:11 PM
Excellent site!!!!!!!!!!!!!!!!!!!!

Mike

Your Old Dog
06-24-2005, 05:24 PM
dp, neat workmanship but I don't like the looks of the setup on the last photo. Seems to me the jack is taking too much of a load for the work that is supposed to get it. Am I right or just being overly critical?

Paul Alciatore
06-24-2005, 05:40 PM
I have one that is about 2" tall and extends for an inch or a little more. It was a advertising give-away from a shop that repaired, you guessed it, jacks. The bottom is a casting and I am not sure it is very strong. Nice toy. I have never had occasion to actually use it.

If I can find it, I will post a pix.

Paul A.

mochinist
06-24-2005, 06:44 PM
<font face="Verdana, Arial" size="2">Originally posted by Gary Rose:
OK, this is probably a pretty stupid question - but so be it. What would these be used for?

I have a pair (still in the original packaging) that I've never seen a need for. I've always been able to use a vise or clamp the work to the table. Any particular application that these are valuable for?Gary</font>

Another use that wasn't mentioned is support for long work that is hanging out past your vise. I machine keyways in shafts ends all the time, alot of these shafts are 3' long or more, the screw jack set at the right height makes it nice and easy, and the weight of the shaft doesn't try and pull it out of the vise.


<font face="Verdana, Arial" size="2">Originally posted by Gary Rose:
[BA friend of mine is a journeyman machinist and told me that they have pretty limited uses and I would probably never need mine. So far he's right.

Gary[/B]</font>

I work as a machinist in a job shop and I bet I use mine atleast once a week, sometimes more sometimes less. I guess it is a matter of opinion and how you were taught to do different operations. I have heard machinist say the same thing about 1-2-3 blocks, I use those daily for different set-ups(2-4-6 Blocks are handy too) but some in the trade never use them.

Once you find a use for the jacks you will see how handy they are and start finding other uses that you hadn't thought of before.

Last Old Dog
06-24-2005, 08:30 PM
Your Old Dog, Me thinks the positioning may have been a quicky for the photo shoot. I agree the three elements of the clamping componants dipicted in this photo do not represent real life setup proximity and spacing.

Gary Rose
06-24-2005, 08:49 PM
Well, it's interesting what you learn when you ask, huh?

It makes sense for using with irregular parts. Since I generally don't work with parts that aren't rectangular-ish it also makes sense that I wouldn't have known that.

I like the idea of using them for making keyways on shafts and supporting long work. Would never have thunk it myself.

You're absolutely right about the 1-2-3 blocks. I had a pair for a long time just sitting until a friend showed me how to use them right. I find myself in situations now where I'm using them all the time. Funny how that is.

Maybe I'll dust off the jacks now...

Gary

ibewgypsie
06-25-2005, 11:46 AM
I have thought of building similar toys to mount the chevy heads on my mill with. A pin where the headbolt goes on top thou.

Cnc'ing heads, polish, throat reduction. I don't have the capabilities of cutting them and rewelding them. But I could work from the pockets down. I did some template porting on some SBC 462 heads that made the car leave the ground at the line.

David

Daminer
06-25-2005, 12:04 PM
Seems that the most common use I have for the jacks is keeping band saw vise jaws parallel while holding small work.....

Jim

dp
06-25-2005, 12:53 PM
<font face="Verdana, Arial" size="2">Originally posted by Your Old Dog:
dp, neat workmanship but I don't like the looks of the setup on the last photo. Seems to me the jack is taking too much of a load for the work that is supposed to get it. Am I right or just being overly critical?</font>


I think that particular photo was intended as an example - in his other projects the jacks show up several times in real situations. I do think a jack should be able to handle 100% of the load and his large diameter (relative) square threads are as strong as it gets. What is missing is a way to lock the jack height but that may not be critical given the thread type and pitch, and the naturally restraining forces of the clamp or vise. A knurled ring nut would be trivial to add. I like the way this design lends itself to extending the reach.

I'm building a set of jacks today based on the hex stock images above just because I have some of that in the iron bin. As much as I hate being on 24/7 on-call for our data center, I do get a lot of work done in the shop :-)

dp

PolskiFran
06-25-2005, 02:04 PM
Quick and Dirty Machinist Jack:

Jacking Screw: 1/2-13x1 hex head bolt (or whatever length you need), face head smooth on lathe to remove grade marks.
Jacking Screw Jam: 1/2-13 jam nut
Body: 1/2-13 coupling nut
Base: 1/2-13 flat head (countersink) screw. Tighten firmly or locktite into base.

Frank

skeeter
06-25-2005, 10:17 PM
One use that I have for the screw jack is to correct a bent shaft. I put shaft in lathe chuck and indicate right at the chuck and then move out to the end. Using the jack and the indicator I can get the shaft straight.

http://bbs.homeshopmachinist.net//smile.gif

skeeter
06-25-2005, 10:17 PM
One use that I have for the screw jack is to correct a bent shaft. I put shaft in lathe chuck and indicate right at the chuck and then move out to the end. Using the jack and the indicator I can get the shaft straight.

http://bbs.homeshopmachinist.net//smile.gif