Fastener testing or pull testing

If you’ve ever performed a fastener withdrawal test, I would like to know your thoughts on the equipment you used. What type of tester did you use? What did and didn’t you like about it? How do you think it could have been improved? Thanks in advance for your replies.

This PDF shows how superior annular or ring nails are to screw and smooth nails: www.apawood.org/pdfs/unmanaged/ WCTENailWithdrawal.pdf

They go into detail of test methods which you are interested in too. There must be some specific purpose for screw nails but the tests make clear they are of little value over standard smooth.

Not really what I was looking for, but you peaked my interest. I tried the link, and it seems to be broken. We (Force-Test) would really appreciate some input to help us make better pull testers.

My suppliers do it for me for free if I buy the screws from them.

Do hundreds of them every year. Anyone that does single ply should have one in their truck. I’ve found lots of decks that seem ok when you walk on them but were only being held together by the existing roofing membrane. Expecially plywood decks. Getting pulls of 110 - 150 lbf.

To address pull testers… too expensive. I prefer digital but the expense of them makes me move to analog. The problem with analog is the difficulty reading the results with any degree of accuracy.

I find the tester has to be calibrated about every couple of years, but can’t find anyone that will do that without charging almost as much as the whole tester costs. In other words, need a guage that is easily and cheaply replaced.

It would be cool if a tester could be built to work with a screw drill…put in the fastener and use the same tool to do the pulls.

Plywood and OSB: Nail withdrawal or holding ability.
As shown in APA report T2001-3A, plywood generally has higher nail withdrawal values using plain-shank, ring-shank, and screw-shank nails, even though OSB has a higher density than plywood. The numbers below reflect dry test conditions. The numbers vary some when tested under dry to wet-redry conditions.

Withdrawal strength (lbs/in. penetration)
Plain
5/8" Plywood Mean: 79.7
23/32" OSB Mean: 67.6
Nail withdrawal strength measures the force to pull the embedded nail from the nailed parts.

To satisfy the need for informational purposes due to the broken link above.

Ed

I don’t know what’s up with that link but this works: bing.com/search?q=nail%20pul … orm=OSDSRC

Just choose the top result which is an APAwood.org test and the pull test PDF will auto load for you.