Aligning V blocks

[mickri]

I am thinking about a couple of projects where I would need to have V blocks at each end of the table on my mill/drill. The slotted portion of the table is 22 3/4" long. The X travel is only 16 1/2." A dial indicator will never be able to reach both ends of the slot without being moved. I don't have a DRO and have no plans to get one. How do I go about aligning V blocks at each end of the table?

 

[Moderatemixed]

I’d put the longest (most accurate) straight edge I have between them and indicate along that straight edge. The longer the edge you can indicate, the more accurate your setup will be. Some of the more experienced guys will likely have a better method but at least you have the “kindergarten” answer covered.


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[tq60]

An adjustable square is perfect for this.

Place one then adjust square from edge of table to block and use to set other.

Next place dial indicator in drill Chuck and round stock on blocks and depending on dial indicator sweep top center or side and tap only one end until the DI indicates true.

Do place DI someplace in the center of your stock and spin stock yo insure it is straight first.

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[RJSakowski]

You really need a straight bar to do it right. Not only do you need to align the central axis of the vee block to the table but the central axis of one block to the other. The straight bar will do both for you.

Clamp the bar on the blocks and lightly clamp the blocks in place. mount a test indicator in the spindle and zero it as near as possible to the vee block. Move the spindle up and down to make sure that you are contacting the bar at the point of vertical tangency. Move the table as near as possible to the second block and repeat the measurement. You should be reading zero again, signifying the blocks are parallel to the ways. If not, reposition the blocks and repeat the measurement.

To check if there is a bend in the est bar, rotate the bar 180º and remeasure. The closer you are to the block, the smaller any runout error will be. If you do experience runout error due to a bend in the bar, you cancorrect by averagng your two sets of readings.The average reading at either end should be the same.