# Retrofitting a 100mm mill vise



## petcnc (Jan 16, 2015)

I always wanted a bigger vise for my little X2 mill. When I bought a 10 cm Kurt style vise  it proved to be  an overkill for my little mill as it had nearly the same size to the mill table.
You can read the full sad story here:





On the other hand the 8 cm Chinese vise I bought with the mill (next to the Kurt style at the above photo), after some retrofit work proved to be precise enough for my workholding needs but has just 6 cm jaw opening, too small to hold something a little larger than a match box.
I saw the offer at arc eurotrade (UK) for a 10 cm vise and I thought the price was right for that amount of metal.




Big-brother-vise has 82mm jaw opening, I think is enough for my needs.

Of course I am aware that all these tools (although certified for accuracy), need some work to bring them up to the standards. In my case the accuracy tests look impressive. 




Watching this accuracy wish list, I suspect though that  test results could not be pre-printed, I expected a testers stamp indicating the test results.
Anyway, the package arrived and I dismantled the vise for inspection cleaning and deburring.




The vise was as expected to be: average design and poor craftsmanship.
I examined all parts and noticed that every single part needed some work to bring it to acceptable level.

*A. Vise Body
*
Starting  with the body it needed minor modifications. Just a good Clean and filing all sharp edges. It also needed filing a dent (a pre-package drop result) on the body (the shiny corner on the photo).




*B. Moving Jaw
*
When I assembled the vise to test for accuracy, I noticed two main issues:

*Issue 1.* Moving jaw had an unacceptable play as there was a gap between vise body and the holding bars (the white area in the next drawing)




*Issue 2.* When the moving jaw opened more than 5 cm it suddenly dropped low at the back ruing any accuracy!!!




Seeking the cause of this drop I noticed that it is a matter of bad design.
Instead of providing a flat surface throughout the full length under the moving jaw, to make it slide smoothly on the body the designer decided (for reasons incomprehensible to me) to provide flat surfaces to the front and the back of the jaw only. 




This way when moving jaw retreats more than 4.5 cm there is no back slide surface to support it and it drops its tail down.
This reduces the usable opening of the new vise to just 5 cm!!!

*C.  Holding Bars
*
Holding bars are plain steel (?) bars cut to moving jaw length with 2 holes on them and no other machining. The surface of the bars was so rough and abrasive that they will be perfect to grind the underside of the body acting more or less as a medium grit sand paper.




*
FIXES
*
*Moving jaw - **Fixing the tail drop
*
I decided to fill the gaps left by designer, with 2 cast iron bars bolted to the side of the jaw.  




Cleaning of the rough side and bottom of the gap was a necessity.




 then cutting to size, threading, bolting and milling cast iron bars to same height was an interesting challenge.




A number of issues had to find practical solutions to achieve that. For example holding the 10cm moving jaw on the existing 8 cm vise!!!




It took 10 times more time to work out holding and leveling the jaw within 0.1 mm than machining it. But the results were very satisfactory.




Moving jaw had now sliding area to all its’ length to move all the way from fully closed to fully opened staying at the same height!!!




*Fixing the holding bars gap
*
After deburring and polishing the steel holding bars it was time to skim the underside of the moving jaw by 0.15 to eliminate play. As you can see the machining at bottom of moving jaw, at the holding bars area, done by the factory was far from smooth and accurate.




After careful milling I skimmed 0.15mm of material, put everything in place and tested the vise. It moves smoothly and has 80mm opening without any play of the moving jaw.




I tested how it fits on the mill table side by side with its’ smaller sibling.




After adjusting hard jaws and bolting it on the mill I can say it: JOB DONE..




*Conclusion*

The money and time spent on the vise was well spent. I have a tool that looks and works as it should and I didn’t break the bank! I’m happy with it.

*The moral of the story:*

If you buy a cheap Chinese tool don’t expect it to be a tool that will work as it should right out of the box! You rather treat it as a kit to work on it in order to make it a proper tool to suit your needs.
 If you do so you will a) be happier b) have a custom made tool and c)save some money to buy other tools to work on them and save money etc. etc.

Thank you for reading

Petros


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## thomas s (Jan 16, 2015)

Well done when you spend the time on something like this and the end result works it is a good feeling. thomas s


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## brav65 (Jan 16, 2015)

Great job!  As a new "machinist" I have learned a great deal work on these Chinise kits. It is always satisfying to accomplish your goal and end up with a precision tool.


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## petcnc (Jan 17, 2015)

brav65 said:


> Great job!  As a new "machinist" I have learned a great deal work on these Chinise kits. It is always satisfying to accomplish your goal and end up with a precision tool.



Thank you, I'm a new machinist myself also and try to make the best out of all these "kits"

Petros


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