Very fundamental guage question

[Phil Mueller]

I've seen "instructables" two ways. When setting a mortise guage, do you set the point of the pins to the outside edge of the chisel, or set the chisel inside the base of the pins?
Or in the grand scheme of things does it really matter?

[Daniel Rode]

You want the outside edge of the lines to match the chisel width. To do that, the pins should be at the edge of the chisel but not beyond. The shape of you pins may make a (tiny) difference as well. The pins by default are conical, so the line widens a bit as it gets deeper but it's such a small amount.

[Warren Mickley]

The object is that you lay out both the mortise and the tenon with the gauge, make the mortise with the mortise chisel, saw to the tenon line. And then the tenon fits right off the saw. I think the best way to accomplish this is to have the points of the gauge correspond to the width of the mortise chisel.

If you find that you are consistently sawing the tenon too fat or too thin and want to make a small adjustment to how you set up the gauge, that is reasonable. Some people file a small flat on the inside of each pin so they can set the gauge by closing up the pins with the chisel between.

[lowell holmes]

Ever since I saw Derek Cohen's post where he made a mark with a chisel on the wood and then setting the mortise gage by that mark, I've used that technique.
Maybe Derek can tell you where to find that post.

[Derek Cohen]

Ever since I saw Derek Cohen's post where he made a mark with a chisel on the wood and then setting the mortise gage by that mark, I've used that technique.
Maybe Derek can tell you where to find that post.

Thanks Lowell.

The thread you are referring to is here: http://www.inthewoodshop.com/Furniture/MorticingByChisel.html

Another article of interest, one that reinforces the point Warren made earlier about marking mortice and tenon lines off the same gauge, can be referenced here: http://www.inthewoodshop.com/ShopMadeTools/Mortice-CuttingGauges.html

This is about the gauges typically used ...

http://www.inthewoodshop.com/ShopMadeTools/Mortice-CuttingGauges_html_mc556f5.jpg

... and the ones I made for myself:

http://www.inthewoodshop.com/ShopMadeTools/Mortice-CuttingGauges_html_1ff5cd98.jpg

Regards from Perth

Derek

[Phil Mueller]

Thanks guys! Very helpful.
Phil