# Interesting discovery on my Excel EC30-B mill/drill



## mickri (Sep 22, 2020)

I have a made in Taiwan Excel EC30-B mill/drill.  I don't trust the dials on my mill/drill to be really accurate.  I have not actually measured how far things move in relation to the dials until today  On the X and Y axis's one rotation of the dial is 0.125.  Checked this with a DI and measured 0.125. 





 I had always thought that one rotation of the dial on the Z axis was 0.100.  Today in cutting the slot for one of the tool holders I am making I decided to try to be really accurate instead of my usual sneak up on it until it fits.  I know that I am a hack at this machining stuff.  Trying to up my game here.

Today I used my wiggler for the first time to find the edge of the tool holder.  Did the math and moved the table in so that the edge of end mill should be where I wanted it.  The edge of the end mill just kissed the layout line I had drawn.  So far so good.  None of my dials have the zero feature.  I can sort of set the Z axis to zero by having the dial on zero but don't engage the fine feed.  I then bring the end mill down to touch the work and engage the fine feed.  When I did this today it looked like the dial was on 9 instead of 0.  Move the dial over and know I am on 1.  What's going on here.  I go through this several times before I take a really close look.  Lo and  behold there is no 9.  The dial goes from 8 to 0.  Checked the travel for one rotation with a DI and got readings from 0.85 to 0.89.  Most were 0.880 and 0.890.  I'll take some more tomorrow.




I can't believe that I have been using my mill/drill for several years and never noticed that one full rotation on the Z axis was 0.900.  Feeling pretty dumb right now.


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## DavidR8 (Sep 22, 2020)

mickri said:


> I have a made in Taiwan Excel EC30-B mill/drill. I don't trust the dials on my mill/drill to be really accurate. I have not actually measured how far things move in relation to the dials until today On the X and Y axis's one rotation of the dial is 0.125. Checked this with a DI and measured 0.125.
> 
> View attachment 338012
> 
> ...



You know, I think mine is like that also. 
Best go check. 
And. 
There’s no dumb here 


Sent from my iPhone using Tapatalk


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## C-Bag (Sep 23, 2020)

This exactly why I went to DRO. Doesnt matter how much backlash or how the dials are calibrated, it shows exactly what is going on. I went the lo buck route and went with igaging setup and it was only $150 for 3axis and when tested were all within .001 in 6” and returned exactly to 0 over many repeats. Major game changer. I just upgraded with the TouchDRO and that’s a whole ‘nuther order of upgrade. Same scales, so just add the Bluetooth box and a Android phone or tablet and voila! Same accuracy but features the expensive DRO’s have. Like the 1/2 feature to find center. I’m just getting used to it, but that feature alone has made life easier. The ap is free too.


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## pontiac428 (Sep 23, 2020)

Me too.  I drilled a hole pattern in a long, thick, expensive piece of aluminum using my handwheel dials and wondered why the part wouldn't line up with the mating part.  Cheap iGauging DRO fixed it, never been a problem since.  I thought it was a metric lead screw and rounding errors, but I really haven't had to think about it since adding the DRO.


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## RJSakowski (Sep 23, 2020)

My 40 y.o. private label RF mill/drill has the same issues.  Reading the traveled distance for every ten turns of the fine feed, I get .8512, .8398, .8518, .8526, and .8506. for an average of .8498".  The dial calibration is .850"/turn.  The variation in readings is due to wear on the worm/spur gear and/or the rack and pinion.  

I installed a DRO on the machine 16 years ago.


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## Mitch Alsup (Sep 23, 2020)

The y-axis on my mill goes 0.999,2 per 8 turns. While accurate enough to most stuff, it is a pain when it is not.


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