Setting up and using V-blocks

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Active Member
Dec 5, 2017
I tried to search on this topic as I imagine it's a common question for beginners, but couldn't come up with a search phrase that led me to anything.

I managed to kludge together a set up to bore a hole in a piece of 5/16th inch round stock for a cotter pin but it was NOT pretty. It presented three major questions:

1. How do you clamp the v-block to the table on the mill? The slots on the sides are too small for a standard clamping kit. I can clamp on the top lip but that gets in the way of things pretty quickly. I milled a step on a piece of flat stock so it would fit in the side slot, but it wasn't very secure. For example, I wouldn't be comfortable milling a flat on a piece of round stock with that setup.

2. The stirrup clamp (if that's the right name) that holds the stock in the v-block gets in the way of the drill chuck pretty quickly. Somewhat better if I'm using a collet and a center drill but still not much clearance.

3. How do you ensure that the v-block is square on the table, or put another way, that the vee is parallel to the t-slots and aligned with the milling head?

P. Waller

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Mar 10, 2018
Put the V block in a vice on its side and use the vice to clamp the part, this is much more secure. If the part is below the top of the V place a piece of square or rectangular stock that is narrow enough to reach the part, parallels work well for this. If a repetitive part mill a soft jaw for this purpose.

Like so

vblock in vice.jpg

David S

Active User
H-M Supporter - Gold Member ($25)
Nov 18, 2012
Mount the V block in the vice as others have said. I find the clamps that come with them also get in the way of the chuck, so I have made some adjustable clamps for my v-blocks.

adjustable low profile clamp.jpg


Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Feb 1, 2018
Many drill press vise have V grooves cut in them for holding round shafts. Vertical for drilling the end and horizontal for drilling across holes for cotter pins, etc. :)


Oct 31, 2016
I have been wondering about this too. One thing that I thought of was to drill a hole down through the block and use a flat head machine screw screwed into a "T" block to clamp the block to the table. And to keep the block from twisting have the T block extend up through the table and fit into a slot on the bottom of the block Did a quick sketch to show what I am thinking. I did not include the screw or the countersink for the screw head in the V in the sketch.

V block 01.jpg

V block 02.jpg
You could also drill and tap holes in the flats on each side of the V to hold clamps to hold the work piece in place.


H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Feb 1, 2015
My short step clamps will seat in the grooves on my V blocks. I usually use them in the milling vise though. When I need more aggressive work hold down, I will use a step clamp rather than the clamp from the V block.
If I need to align the V with the x or y ways, I will sweep one of the outside faces of the block.

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Jul 2, 2014
When drilling round stock it also helps to mill a small flat with an end mill before drilling the hole to keep the drill from deflecting off center.
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