# Force required to pull a roofing nail out of decking

1. Feb 12, 2019

### Akita

1. The problem statement, all variables and given/known data
Roofing coil nailer drives with 430 in lb into plywood,decking 1.5" nail
How much force do i need to pull the nail out ,i dont know what else holds nail in place other than friction
ELI5 ,im as uneducated as it comes. :D
2. Relevant equations
i dunno any

3. The attempt at a solution
googled few hours but lacking of actual knowledge makes it hard to find needed formulas,theorems what forces apply to this

2. Feb 12, 2019

### Staff: Mentor

Welcome to the PF.
That's a very challenging and practical problem. Are you told what tolerance your answer needs to be within?

I would start by looking at the coefficients of static and dynamic friction between the nail metal material and the wood material. Then I would look up the spring constant of the plywood (as it's deflected out of the nail hole). Can you find those numbers and say what you would do next?

3. Feb 12, 2019

### gleem

What is the nature of the data that you are provided? That is what is 430 in-lbs and what is the value of knowing the nail length.?

4. Feb 12, 2019

### Akita

i found some data Nail Withdrawal and it says 2 inch nail uses 59 lb in OSB 7/16,id guess double that in pine planks so 100 lb.
430 in lb is for coil roofing nailer force ,for 3/4 to 1 3/4 nails
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im designing wedge acting tear off tool for shingles and wanted to calculate how much force would i need to push out or pull out with fulcrum from above materials.
How to correlate 59 lb in given data to force in Nm ,thank yoyu guys for feedback,not knowing stuff is kinda painful :D

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5. Feb 13, 2019

### phinds

I doubt if that is as helpful as you might think it is. The problem is that this is an amount of force that DEFINITELY will seat the nail. That is, it is more force than is needed but you don't know by how much.

6. Feb 13, 2019

### Akita

i got it,all numbers kinda straight now. thank you guys.

Last edited by a moderator: Feb 14, 2019 at 11:11 AM