Towards accuracy on your milling machine
One factor sometimes not appreciated by those new to model engineering is the necessity of squaring up and levelling the vice on the milling table. Unless this procedure is carried out with great care care there is little hope that work produced on the mill will be to the required accuracy.
For this important task you will need a DTI (dial test indicator). I prefer the more versatile lever style than the plunger type. Take a look the offerings of Arc Euro Trade.
Click on any of the images for a larger view
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- You will need one of these - a dial test indicator, DTI. Choose one with a lever probe rather than a plunger.
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- Mount the DTI in the mill chuck and position so that the probe is central on the top of the rear vice jaw. Zero the dial.
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- Movement of the dial away from your zero setting indicates all is not true and some adjustment is required.
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- The chances are that you will discover that your vice is not truely level and observation of the dial will indicate to you which side of the vice needs raising.
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- By inserting shims under the appropriate side the vice can be raised. Mine for example needs 10 thous on the left. Cut up a cheap feeler gauge to obtain shim material.
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- Once you have your vice levelled use a similar technique on the face of the rear jaw to align your vice parallel to the table. This is where the lever type of DTI is useful.
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- Moving the vice along the 'x' plane will indicate any misalignment which can be corrected by gentle nudging with a soft faced hammer.
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- A similar 'squaring up' procedure should be carried out each time you mount your rotary table on your mill.
