Newmar interior screws?

[FatChance]

We have a 2004 MADP. Newmar used square drive/Philips head self tapping screws to hold nearly everything together in the interior. Is there a technical description of those screws that would make it easy to find replacements? I use a #2 square drive bit on them but is there a better bit? Are the screws pretty much the same as Kreg screws?

[dms]

Newmar uses mostly "square Drive" pan head screws. They can be found at a Fastenal store, or Lowes, Ace, Home Depot, etc.

Pan head = rounded head
Flat = flat head.

[Bob_C]

Square drive is called Robertson.....and use a #2 bit

[Unplanned Tourist]

"Square drive" is that Robertson you are talking about? If so, they are a Canadian thing. Invented by a guy named P.L.Robertson, or should I say he developed a system to make them.
For some reason they never really caught on other places, but they are used lots in Canada.
I have a 1928 Model A Ford Tudor that was made in Canada. It has all Robertson screws. The US made ones had flat head (slotted) screws.
Just some trivia for you.
Happy Glamping.

[FatChance]

They are not Robertson nor usual square head or Philips. They are a combination Philips and square drive. You can use either a #2 square drive bit or a Philips head bit. The head is domed similar to a pan head and has a flat base. Maybe DPD2-2? Maxi-Lok? Kreg?

Hopefully this picture will help, but you may need to magnify it a little.

[Bob_C]

They're used because they are almost impossible to round out....most RV's are put together with screw guns.....

[FatChance]

Here is another picture, this one is from a cabinet screw. I want to find out what they are called so I can order some more.

[TJ]

They are called "combination" or "combo" head screws...for obvious reasons. They are simply a Phillips and a square/Robertson drive superimposed on the same screw head. The "combo" head uses a #2 square drive bit...or, a #2 Phillips; either will work.

I suspect this screw head style is produced to facilitate sales in both the US and Canada where different styles prevail in each country.

TJ

[WoodyS]

Most RV's appear to be using mostly #2 Robertson Square Drive screw heads now. Our 2003 Chinook uses them, our 2005 Cardinal/Americana 5th Wheel trailer uses them, and our 2008 Kountry Star uses them. But they aren't all the same -- not even in the same coach. Some are flat-head, some are round-top head, some are washer-head, some are combination #2 Robertson and #2 Philips -- in round top, washer-head, flat-head, etc.

And the threads aren't the same either. Some are fine thread, some are coarse. Coarse or fine threads "should" relate to the material they're being screwed into. Soft woods (pine, fir, poplar etc.) "should" have wide deep coarse threads, while hard woods (oak, maple, etc.) "should" have narrower thinner fine threads.

But in reality -- I think the installers just grab a handfull of whatever is handy or available at the time.

Also realize that a lot of the stuff inside your coach wasn't made by Newmar, but by various sub-contractors. So taking our "Pacific Cherrywood" desk/table for example. The screws holding the table/desk together are mostly flat-head #2 Robertson screws. But the screws fastening the desk/table to the floor are different because they were installed by Newmar.

I'm pretty sure I've run into a couple of #1 Robertson Drive screw heads also. And most of the screws in the metal parts of our basement storage compartments (door hinges, struts, etc.) are self-drilling "TEK" screws with #2 Philips pan heads.

If you're trying to minimize the number of tools you carry, good luck! I've also found that I had to buy a full set of Chapman Mfg.'s tiny narrow clearance right-angle tools and bits because no "regular" screwdrivers (including "Stubby") would allow me access to many screws -- Robertson and Philips). For example, working on the window valences can require the really short right-angle Chapman tools and bits.

[dennis45]

Originally Posted by Unplanned

"Square drive" is that Robertson you are talking about? If so, they are a Canadian thing. Invented by a guy named P.L.Robertson, or should I say he developed a system to make them.
For some reason they never really caught on other places, but they are used lots in Canada.
I have a 1928 Model A Ford Tudor that was made in Canada. It has all Robertson screws. The US made ones had flat head (slotted) screws.
Just some trivia for you.
Happy Glamping.

To Remain Politicaly Correct,

The Phillips/square screw drive, also known as the Quadrex, Pozisquare screw drive, is a combination of the Phillips and Robertson screw drives. While a standard Phillips or Robertson tool can be used, there is also a dedicated tool for it that increases the surface area between the tool and the fastener so it can handle more torque.

Recex
The Recex drive system claims it offers the combined non-slip convenience of a Robertson drive during production assembly and Phillips for after market serviceability. The Phillips Screw Company offers both Phillips and Pozidriv combo heads with Robertson.

[hohenwald48]

There are about a zillion different varieties available on Amazon.

[TJ]

Originally Posted by dennis45

To Remain Politicaly Correct,

The Phillips/square screw drive, also known as the Quadrex, Pozisquare screw drive, is a combination of the Phillips and Robertson screw drives. While a standard Phillips or Robertson tool can be used, there is also a dedicated tool for it that increases the surface area between the tool and the fastener so it can handle more torque.

Recex
The Recex drive system claims it offers the combined non-slip convenience of a Robertson drive during production assembly and Phillips for after market serviceability. The Phillips Screw Company offers both Phillips and Pozidriv combo heads with Robertson.

Interesting! A little research indicates that the "dedicated tool [bit]" you mentioned is frequently referred to as a "PSD2-2" or a "Unidrive" bit. Apparently, even some of the big-box stores carry them.

Learned something new today!

TJ

[twojayhawks]

I would not replace a self tapping screw with another self tapper- the hole is already drilled right? Too many of my self tapping screws put in by the Newmar craftsmen could be removed with your bare hands. I've had to replace a few and chose to slightly upsize the fastener.

[FLSteve]

Originally Posted by Tranquil Jim

Interesting! A little research indicates that the "dedicated tool [bit]" you mentioned is frequently referred to as a "PSD2-2" or a "Unidrive" bit. Apparently, even some of the big-box stores carry them.

Learned something new today!

TJ

Me too and I just ordered a couple of those bits just to have.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

FLSteve