Screws or no Screws ... That is the question!!

[Southern1]

A big sheetmetal project we are working on has hundreds of fan coil units. They are 400 CFM units and the static pressure is fractional. There is 10 x 8 26ga. duct coming off these units.

The superintendent has been in sheet metal for about 2 years and wants to put 3 screws in each snaplock seam and one screw in each drive fold over at the joint. That makes 16 screws in a 10' section of duct.

They are knocking together all the duct in the shop and pre-fab the 10' sections. I agree that ONE screw may be needed to keep the snaplock from slipping and that's all.

I'm the estimator and I feel like the extra time and cost will affect the budget.

I'd like some feedback on this to determine who is right.

Thanks,

[device]

i dont think it is necesary at all..but if he insists mayby @ each end ..
its only 400 cfm ..10 x 8 duct it is so not needed.hmm 10 foot sections..

[Southern1]

Its two 5' sections S-lock and drives.

[ccrayjr]

One screw in the center of each 5' section

[Apprentice]

One screw in the center of each 5' section

Agreed, exept I would put a screw on either side to make it look uniform and to hold it from moving in the future and becoming twisted. 2 screws are not going to hurt anything.

[Southern1]

Yeah... I feel one screw in each snaplock seam is enough.

[sheetmental]

see what smacna says. i bet none are required at all. 26 ga, 10" wide with a snaplock on one end isn't likely to have alot of flex. it's not like it's going to "oil can" or anything.
on a job like that, the money is in the man hours saved. it's all about speed. if someone insists on screws, one in the center of each joint is more than enough.

[thehammer]

A big sheetmetal project we are working on has hundreds of fan coil units. They are 400 CFM units and the static pressure is fractional. There is 10 x 8 26ga. duct coming off these units.

The superintendent has been in sheet metal for about 2 years and wants to put 3 screws in each snaplock seam and one screw in each drive fold over at the joint. That makes 16 screws in a 10' section of duct.

They are knocking together all the duct in the shop and pre-fab the 10' sections. I agree that ONE screw may be needed to keep the snaplock from slipping and that's all.

I'm the estimator and I feel like the extra time and cost will affect the budget.

I'd like some feedback on this to determine who is right.

Thanks,
UGLY!!! YUK!!!BLAH!!!
Please no! Have you no pride in your work??or just no experience?
If your snap lock does not hold together_ adjust your machine. You do know there is an adjustment when you go to light gauge.
Furthermore properly hammered over drives do not need screws. I would be embarrassed to hang duct full of screws, it would hurt my eyes. Sounds like too many butchers trying to do sheet metal these days. That's only my opinion after 30yrs in the trade. Sad to see true workmanship is disappearing at an alarming rate:evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil:

[CadMan]

UGLY!!! YUK!!!BLAH!!!
Please no! Have you no pride in your work??or just no experience?
If your snap lock does not hold together_ adjust your machine. You do know there is an adjustment when you go to light gauge.
Furthermore properly hammered over drives do not need screws. I would be embarrassed to hang duct full of screws, it would hurt my eyes. Sounds like too many butchers trying to do sheet metal these days. That's only my opinion after 30yrs in the trade. Sad to see true workmanship is disappearing at an alarming rate:evil: :evil: :evil: :evil: :evil: :evil: :evil: :evil:


I'm with you! I've been in the trade 15 years and hate to see it come to that. Actually I'm a Project Manager now and would question any of the men on my job for screwing this together. Seeing it from both Management and the Field/Shop side I would adjust your machines if you need. Beat on the S/D's and seal accordingly. That is all SMACNA requires anyway.

[danfry1022]

How do you become a superintendent in 2 years? I would assume that he has no knowledge of mechanical sheetmetal. If you seal your duct with sealer the snap lock is not going anywhere. I could not work for this guy. I have been doing sheetmetal for 22 years and it all boils down to "time is money". I hate it but I think this trade is going to hell in a hand basket.

[Southern1]

I agree it makes me sick to see them putting so many screws in the duct.

[Southern1]

There is nothing wrong with the snaplock machine. I went in the back and snatched on the metal and it didn't even try to budge.