[RE-wrenches] IMO - SS Tek Crews

[Nick Soleil]

I agree with that Jim:
    I wouldn't do it without the 32 threads per inch, but have decided to bolt the lugs to the modules (with a star washer, of course.)  It is only for this one job.

 Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell:   707-321-2937
Office: 707-789-9537
Fax:    707-769-9037




________________________________
From: North Texas Renewable Energy Inc <ntrei at earthlink.net>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Sun, October 25, 2009 9:27:28 AM
Subject: [RE-wrenches] IMO - SS Tek Crews

Self drilling screws are OK for conduit clamps, wire clips and other 
miscellaneous uses but I would never recommend them for anything structural. 
Drill points on screws are not going to be accurate nor the drilled holes 
clean. And threads that cut into those holes won't be strong. Holding 
strength comes from correct thread mating, it's friction from thread contact 
that keeps it in place.
Look at this spec sheet for 1/4" stainless self-drill screws and you see 
that it's only 14 threads per inch, not 20. 
http://www.fastenersuperstore.com/productSheets/SelfDrillingScrew.pdf
Self tapping screws, the ones with the 3 sided thread forming ends and hex 
head are nearly as good as a properly tapped hole in aluminum. A #7 (.201") 
split-point stub (aircraft) drill will drill thru a 1/4 of aluminum in 1 to 
2 seconds without walking. A 1/4-20 screw will cut threads the entire length 
of the hole and  the screw will not come out.
In my previous life as a machinist for almost 20 years, a few things have 
stuck with me like the importance of proper cut threads. Besides, driving 
home a self-drilling screw will run down drill batteries a lot quicker than 
a sharp drill bit.
my 2cts....
Jim Duncan
North Texas Renewable Energy Inc
817.917.0527
ntrei at earthlink.net
www.ntrei.com


----- Original Message ----- 
From: "jay peltz" <jay at asis.com>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Friday, October 23, 2009 10:18 AM
Subject: Re: [RE-wrenches] SS Tek Crews


> HI Guys,
>
> Check out dynamic fastener,
>
> they have a lot of great stuff.
>
> Including self drilling 1/4x 20 SS screws and larger.
>
> jay
>
> peltz power
> On Oct 23, 2009, at 3:12 AM, Carl Adams wrote:
>
>> Hello Wrenches,
>>
>> Pulling up this thread from earlier in the year.  I have a couple of
>> upcoming jobs where I am attaching PV mounting structure  as follows
>> Job 1) LFoot to metal roof into Z purlin, and Job 2) FastJack to metal
>> roof into bar joist.
>>
>> In both of the applications I'm considering the Tek screw type
>> attachment to the building steel.  Both the L foot and FastJack are
>> sized for a 5/16 - 3/8 lag or bolt.  Most of the self tappers I see
>> are 1/4" max diameter.  Should I be concerned about the undersized fit
>> of the fastener in the mounting attachment or are there large Tek type
>> screws out there I'm not finding?
>>
>> Does anyone have pullout strengths for this type of attachment?
>>
>> With Regards
>> Carl Adams
>> NABCEP Certified PV Installer
>> SunRock Solar, LLC
>>
>> On Thu, Feb 5, 2009 at 6:51 PM, Peter Parrish
>> <peter.parrish at calsolareng.com> wrote:
>>> Does anyone have a source for stainless steel, self tapping Tek  screws? 
>>> I
>>> could use some #10/3-4 and #10/1-1/2. If they have the little cap and
>>> neoprene washer that would be even better!
>>>
>>> - Peter
>>>
>>> Peter T. Parrish, President
>>> California Solar Engineering, Inc.
>>> 820 Cynthia Ave., Los Angeles, CA 90065
>>> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
>>> CA Lic. 854779, NABCEP Cert. 031806-26
>>> peter.parrish at calsolareng.com
>>>
>>>
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