Surface plate question

I pretty much fooled away the whole afternoon messing with this. Thought it might be the vise so I removed the jaws and cleaned all the surfaces and reinstalled. It's a no name piece that came with the mill, no markings on it anywhere

I have all 4 sides milled now and they (to me anyway) look pretty good but I can only get it to hold one of the parallels tight. The one against the non fixed jaw or the other depending on which way I put the block in is always loose so I have been chasing my tail here.

I removed the vise and checked the tram again nothing changed there, I reinstalled the vise and did the same to it as well.
My son suggested we place the sawed end down to start and that's what we did and I suspect the issues I am having now all stem back to that.

If I keep whittling away on this sinker I won't even have enough left to make a decent paper weight the rate I'm going!!o_O
 
Guessing the accuracy of various things in the shop is a waste of time. Usually it is actually hoping, hoping it is not as bad as you fear it is. Accuracy cannot be guessed, it must be tested and proven. Depending on the accuracy needed, different tooling and setups can do the job, but no guessing! Hoping is a wonderful thing, but it is useless at proving accuracy in the machine shop. Many projects and repairs do not need high tolerance flatness, angles, diameters, and fits. Understand what you need to accomplish, learn what it will require to achieve it, and acquire the needed skills and equipment. Taking short cut guesses toward accuracy is just kidding yourself...
 
Something is off. Indicate the inside bottom surface of the vise to see if it is parallel to the base/table. Then, if your mill will, indicate the fixed jaw by cranking the knee up/down to see if the jaw is perp to the base/table.

And just to be sure about your technique
 
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Just watched that video and I think I'm going to sleep on this one a few nights!
I used the wire trick a couple times and told a friend about that. He said that was just dangerous and should not be done???
Thinking now it must be the vise or the Y tram?? I'm near dead on for the X axis.
Will be making a trip to town later today and will visit the machine shop and have a look through his drop bin and see what turns up.
Perhaps aluminum would be a better choice for this being easier to work with.
In the meantime, I'll recheck the vise.
Trying to get this as near correct as possible just for the heck of it and to prove to myself that an old retired trucker can do this.
Thanks for the input folks!
 
You can roughly check the flatness of your cast iron table with a straight edge and feeler gauges. In my experience you tend to get some dips between bracings in the castings, could be off by .005" or so.
 
As mentioned above, plate ("shop window" in those UK workshop books) glass can be used as a surface plate, meaning it can be used as a reference when making a surface plate. You can also use the ways of a lathe as a reference: put the plate on the carriage, an indicator in a surface gauge on the ways, and run the gage back and forth to get readings of the surface, incrementing position with the carriage between sweeps.

In regards to the squaring, there are a few things to check: burrs on the corner of the workpiece, the vise itself lifting when clamping force is applied, that sort of thing. Put an indicator on the work when tightening the clamp in the vise and see if it moves. If there is movement, you may need to pound the piece down with a hammer, or put a shim on the opposite end - or it could just be loose vise faces. Also, try putting some vaseline on the parallels to hold them in place while you tighten the vise - it could be that one of them is moving up and throwing off the other.
 
Old Cubs are worth the expense , buy a AA plate ! :big grin:
 
finsruskw said:
Just watched that video and I think I'm going to sleep on this one a few nights!
I used the wire trick a couple times and told a friend about that. He said that was just dangerous and should not be done???
Click to expand...

I've done it lots of times, usually with a piece of round stock or a dowel. It's not dangerous, you're taking light cuts just to square the faces.
 
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