On Monday, March 27, 2017 at 9:45:01 AM UTC-5, Ivan Vegvary wrote:
Need to cut stringer with 16 risers, each at 7.33 inches. (total 117-5/16").
Have a decent square and pair of gauges (clamps) that I acquired way back in the 60's.
Question: If I am off only 1/16" per tread, and it's accumulative, I will be off an entire scary one inch.
How do I conveniently measure total rise while the stringer is still on the saw horses, laid out but uncut?
Don't care if any riser is off by 1/16", simply don't want it to accumulate.

Thank you for all replies. No, too inconvenient to put riser in place. Job is 26 miles away.

Ivan Vegvary

I sounds like you are more worried about the layout and cutting than the math. Yes?

We used an old steel square with masking tape on it to layout stair when I was a framer. Personally, I liked it better than the knobs you set to repeat your layout that they started selling. We also used a Swanson framing square from time to time. With careful cutting, careful layout with a thin lead pencil, and careful measurements to begin with, everything worked out fine. I would cut the stringers on one house and have one of my helpers come get it to take to another house for installation. If your math is solid, you will be fine cutting them somewhere else.

As MIKE pointed out though, you need one more measurement. You need 1) the width of a tread or 2) the opening of the overall dimension in which the stringer sits. You can backwards engineer to come up with your final numbers that way.

So back to the "cumulative effect". Don't worry about it! If you are off, you will know when you lay it out. The tread will tell the tale. If you make a determination that (for example) that your tread will be 8 1/2", then do a test layout on your stringer with your rise/run layout. (Remember to crown your stringers!)

If you cannot fit a whole tread at the last cut step then your run measurement is off. If you have some left over, same problem, other direction.

You cannot do exceptionally long runs on stairs anymore, but at one time you could have really long runs. I am saying this because I don't know what you have, but when I had to cut those, I simply cut the run in half, figured that would be half the stringer and checked my layout at that point. If it was off an 1/8" or 3/16", it didn't matter as I could take it out over a couple of stairs or simply leave it alone and start over on the second half of the stringer layout. Neither of those measurement will be apparent to anyone, and when I was off 1/4" overall and I cut and installed it unless it had hardwood treads. For carpet treatment, you can be off 1/2" at the top and no one will ever see it. I have worked in houses that had all different sized treads all the way up, but since they were covered with carpet no one (including me) knew it until we took things apart.

Here's a good trick. Once you work your numbers out to your satisfaction, put the stringer with all your calculations and layouts aside and used the numbers you developed on a fresh stringer. Carefully lay it out, cut it, then use it as a pattern for the other stringers. I hate creaks, so even on houses that called for two stringers, since I had a pattern, I cut three with little more effort.

Hope that helps.

Robert