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When I asked Mikini about tramming, they said that it didn't need it and that there are no ways to do it outside of their facility and that the end user should never attempt it. I never felt it needed it but I never really carefully checked.
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Hello folks, As I have mentioned in another post, I recently finished my first set of parts on the mill. Although I was happy in getting them done, I just didn't think the finish was up to snuff. By that I mean, the parts had a somewhat dished look (concave) about them. I checked this using a precision straight edge and a flash light. Sure enough you can see light come through in spots.
Anyway, I never really checked the tram on the mill, so I decide now was the time. Before I jumped into anything, I researched all I can about tramming. I found Hoss's videos very informative...Here's part #1
http://www.youtube.com/watch?v=40Q61UAnOTA]G0704 Tramming Part 1.wmv - YouTube
I started by checking the spindle to the column, using the RDM method used in the above video. My drill rod measured 8". I started at the top...centered my "0" and moved down to about a half inch from the end of the rod
The spindle was out by .002 fore and aft. I needed to shim the front of the spindle.
The Mikini really doesn't have any place to place a shim, other than under the spindle. As the head is bolted directly to the linear bearings. So I loosened the 6 Allen bolts that hold the spindle in place and gave the spindle a light tap downwards. This gave me enough room to place a .001" shim between the spindle collar and casting. Also, the shim is only .250" wide x
.750" long....only about .250" is inserted into place..the rest is used as a handle
I rechecked the runout and all was good, as I had even readings on my dial test .
Now it was time to check the left and right runout. Here I was out close to .0045" out of trueThe shims were installed on the left side of the spindle. The best I could get was about .00003" runout at the bottom of the rod. Which isn't to bad for what I do.
Now it was time to tram the head to the table. Btw, I'm using the same setup as Hoss has in his videos.
I started out checking the front to rear. Here I was out by .004" , the odd part here is that it was leaning backward. Normally, you would think the mill would nod forward. Anyway, I loosened the six large Allen head bolts at the base of the mill ( I used a ratchet with an Allen wrench socket )....just enough to be able to rock the mill and place shims on both sides of the rear....about .0025" in this case.
After getting even readings front to back....I checked my left to right position...again I was out by .0045". I needed shims placed on the left side of the column. After all was said and done, the only spot with no shims was the front right corner ....
Being that I'm a rank beginner at this milling stuff, the above took me about 6 hrs to accomplishBut, it was worth it..... I made the Mikini a bit better and exercised this old man's brain cells a bit
When I asked Mikini about tramming, they said that it didn't need it and that there are no ways to do it outside of their facility and that the end user should never attempt it. I never felt it needed it but I never really carefully checked.
Here are some pictures of where i installed the shims.
Here is the spindle .....
and at the base of the column....
I've also put together another computer...you can see it in the first pic. It's a Shuttle computer case, that I modified to accept an Intel mini itx mother board...similar to what Allen has in his retrofit. I also mounted the second breakout board inside the computer case...as well as my smoothstepper
I had issues with the smoothstepper and my spindle control initially, but, I believe by installing it inside the computer case and using the computers ground and such... sorted out my electrical noise problems with the smoothstepper.
I'm really impressed on how smooth the steppers run, very noticeable
I have a story from yesterday that is relevant to this thread. I began the day trying to square up some stock for fixture plates and cutting into smaller blocks for parts etc. I tried facing the bars but something wasn't quite right. The face mill was leaving trailing marks on the surface, which it never has before. Then I notice the after facing two adjacent sides the bar would wobble when placing it against vice jaw so something wasn't right there either. I first suspected a stray chip preventing it from sitting flat but even after thoroughly cleaning all the surfaces as well as the bar and filing off the bead off the edge it was off square about .01 over 3 inches.
So I figured that since I repositioned the vice the night before I must have got a stray chip under it making it slightly off square. So I removed the vice and since I needed to do a very short job with the vice on it's side I though this would be a good time to do it since I'm taking the vice up anyway. So I did that job but it had a terrible surface finish which was quite odd. I noticed that when starting the spindle it kind of looked like the .25 endmill was wobbling in the ER collet chuck, but I assumed it was because the endmill had some Al marks on it so it was an optical illusion. Then when I removed the tool I noticed the drawbar wasn't tight even though I know I tightened it as I always do.
Anyway I went ahead and re-positioned the vice normally after carefully cleaning all the surfaces, and resumed facing the stock bar but the problems persisted. Not square with trailing marks and a worse finish. So I thought maybe the vice itself isn't square as in the fixed jaw to the bed, but I confirmed it was square with a 1-2-3 block. Totally perplexed I got out the 3D taster and began precisely measuring the square on all surfaces of the vice as it relates to the spindle. It was perfectly square on all axes to at least within .0001, in other words there was no perceptible movement of the needle on the dial.
So I determined that the only possible variable is the facemill itself is somehow not cutting square so I took the tool out and inspected it but I didn't see anything obviously wrong with it. Then I inspected the taper spindle bore and lo and behold there was a dent in the face of it that caused a slight bulge in the front edge of the taper. So I carefully filed it down and smoothed it out with some fine sandpaper and steel wool and reloaded the tool and cut a pass. Finally no trailing marks and a perfectly glass smooth finish. That also explains the poor surface finish with the endmill and the strange wobbling. I ran out of time to face an adjacent side to check square but it should be good now, I'll check next time.
Thinking back to the day before I recall changing a tool and what might have caused the dent. After unscrewing the drawbar the tool normally sticks but this time it just fell out on it's own weight (heavy tool). I was holding it but wasn't prepared for it to freefall so it came all the way out before I jerked it back up to prevent it from hitting the table and I must have hit the spindle face hard enough to cause the dent. I spent all day trying to figure that out. Lesson learned.
Last edited by SWATH; 03-05-2012 at 11:48 AM.
Last night I tried to square two side but I had the same problem of being out of square. To make a long story short I determined it is an issue with the fixed vice jaw. When I clamp something in the vice near the top (as I mostly do) it somehow tilts the vice jaw open so when I put in a 1-2-3 block and have it square to the bed there is a slight gap near the top between the block and the vice jaw. Then when I clamp something near the bottom of the vice jaw and then take it out and check for square, it is square. So this means the fixed vice jaw is shifting a little depending on where you apply clamping force. The bolt are tight. Has anyone heard of this before?
What sort of vise?Originally Posted by SWATH
The Kurt Anglock vises have an adjustment that cheaper clones may lack.
It's a Glacern vice but I think I figured it out. Today I took the fixed vice jaw off to check behind it. There was a little build of of crud in between it and the vice body, so I cleaned it good then remounted the jaw. It's is perfectly square now. I think the bolts holding it must of slightly loosened and allowed crap to get crammed in there. But it is cleaned out now and the bolts re-tightened.
You might want to check here:
http://www.kurtworkholding.com/docum...nline_D688.pdf
for tips on adjusting the "spherical segment" feature of Kurt vises. From pictures on Glacern's home page it looks like they use the same thing.
Mike
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