aptruncata Posted January 25, 2013 Share Posted January 25, 2013 A question that's been lingering in the back of my mind for a bit. I've noticed that all the screws (interior and exterior) are square drive screws. Is there a reason for this? tamper resistance? Some of them have rusted quite a bit and they're not as common as the standar phillips. thanks Quote Link to comment Share on other sites More sharing options...
Dolphinite no longer here Posted January 25, 2013 Share Posted January 25, 2013 Beats me. Are other Sunraders put together with square drive screws? I've only been in one Sunrader and I didn't notice the screws. Maybe the factory got a hot deal on square drive screws the day yours was put together. It could happen... John Quote Link to comment Share on other sites More sharing options...
WME Posted January 25, 2013 Share Posted January 25, 2013 Speed in screwing things together Quote Link to comment Share on other sites More sharing options...
sdboltdude Posted January 25, 2013 Share Posted January 25, 2013 my mini cruiser has torx screws (square) Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 26, 2013 Share Posted January 26, 2013 Those are Robertson screws invented in Canada in the early 1900 They were made to be driven with power tools. You'll find them on most motor homes and wood working stuff (pocket screws) even electrical boxes. They don't slip our jump out of the drivers like a Philips head (invented a few years later in the US). Torx heads are a recent design often called star drive. There must be 2 dozen different designed screws used over the years. Quote Link to comment Share on other sites More sharing options...
aptruncata Posted January 26, 2013 Author Share Posted January 26, 2013 okay, good to know it's not just mine. Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 A question that's been lingering in the back of my mind for a bit. I've noticed that all the screws (interior and exterior) are square drive screws. Is there a reason for this? tamper resistance? Some of them have rusted quite a bit and they're not as common as the standar phillips. thanks If you buy yourself a "trailer scewdriver" with a square drive - keep in mind there are several sizes. RVs typically have a mix of two sizes. My 1918 Ford Model T has a lot of square drive hardware in it. As does the new deck I just built. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 26, 2013 Share Posted January 26, 2013 Yep, a Canajun thing. Since they're so scarce in the US they're almost as good as a tamper resistant screw. I think I read that Henry Ford was trying to strong arm Mr Robertson into some sort of an exclusive deal which he declined. Most common size is the #2. Quote Link to comment Share on other sites More sharing options...
Maineah Posted January 26, 2013 Share Posted January 26, 2013 Most big box stores have Robertson tips to fit 1/4" hex tools. Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 My 1980 Sunrader has square drive screws. Glad it does as it makes removing the old ones easier. I love square drives, always opt for them when I can get them. Have invested a mini fortune in new stainless steel screws to replace all the old fasteners that were starting to rust. Some of the old stainless square drive screws on my rig were very corroded. I bought a few boxes of the most common sizes of those screws to have on hand so I could replace them as I was working on my rig. If your old screws were "heavily corroded" I doubt they were stainless steel unless the RV was parked around salt-water. Even then a good grade of stainless wuld still resist the corrosion. Was Sunrader known for using any Stainless? I ask because I've have never found stainless-steel screws or bolts installed OEM in any RV unless made for a marine environment. Stainless steel is weaker then the much cheaper galvanized steel screws (common choice of RV makers). I've had type 316 stainless steel screws in boats that have been in an out of salt water for 40 years with no corrosion. I use the cheaper type 18-8 stainless in autos and RVs and have never had one corrode yet. Standard stainless steel hardware is weak and not even as strong a common grade 5 steel hardware. There are special SS alloys like 316L and A286 that are similar in strength to grade 5 hardware but they are pricey. Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 Yep, a Canajun thing. Since they're so scarce in the US they're almost as good as a tamper resistant screw. I think I read that Henry Ford was trying to strong arm Mr Robertson into some sort of an exclusive deal which he declined. Most common size is the #2. Not scarce in the US at all. 30-40 years ago yes. Back then they were mostly found in RVs and trailers and often called "trailer screws." Now they are very common in house construction (ever since battery powered screw guns came into vogue). Phillip head screws were developed to use in things like "Yankee Screwdrivers" that were hand powered and push force kept the drive-connection tight. When battery powered screw guns became popular in contruction and high tensile screws got used in many areas that used to be nailed -square drive became the norm. Lately it seems to be a contest between square drive and star-drive for high tension screws. Try to put a 4" long deck screw into some hard southern yellow pine and you quickly find out why star drive is getting popular and phillips just about never used anymore (for screws needing high torque). Now - a "Bristol" drive is still uncommon. I just had to special order some new Bristol bits. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 26, 2013 Share Posted January 26, 2013 Scarce enough that there are still a lot of people that have to ask what they are and don't own a Robertson screwdriver! Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 Scarce enough that there are still a lot of people that have to ask what they are and don't own a Robertson screwdriver! If you go to a building supply store or chain e.g. Lowes or Home Depot - each box of deck screws comes with a bit - regardless if square drive or star. The bit is often worn out by the time a box is used up. In the age of battery screw guns - bits are all that are often needed now. Back late 60s when I first worked at an RV place - we had "trailer screwdrivers." They came with 8 interchangeable bits. Two squares, two clutch heads, two Phillips, and two flat. I still have a few laying around. I don't see "clutch head" screws around much anymore. Quote Link to comment Share on other sites More sharing options...
waiter Posted January 26, 2013 Share Posted January 26, 2013 I go to a "packaging" convention every couple years to see the latest and greatest in packaging and assembly equipment.Look on the assembly line, attachments (screws) are often done with a gun that is feed with a ribbon or canister (a high capacity magazine). Pull the trigger and you get screwed, sorta speak.. no need to start or handle the individual screw. just pull the trigger and in goes a screw.Anyway, Phillips work great in these assembly applications, but they cannot develop the torque and the head will slip and strip out. This isn't a problem with the square heads, the engagement is positive. At the trade shows they like to show a stripped out Philips head, where the square head screw will literately break at the shank before the head strips. And of course if the salesman is worth his weight, he will point out that the line must now be stopped, and the offending screw must be removed, and this doesn't happen with the square drive.In our application, either one would probably be acceptable, but it's whatever they used on the assembly line. John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
fred heath Posted January 26, 2013 Share Posted January 26, 2013 Just a quick note on SS screws. Even with the square drive the have a tendency to "round over" when applied with a screw gun or drill. As Karin said, the metal is very soft. Usually happens when your about 3/4 of the way down. Hopefully you have enough screw remaining to use a small pair of vice grips to remove the damaged screw. Had it happen more times then I can count. Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 Where was that stated i.e. "As Karin said, the metal is very soft . . " ? I mentioned that commonly used stainless is weaker then common steel grade 5 hardware. 316 and 18-8 is the most common for SS screws and is in between Grade 2 and Grade 5. 18-8 stainless steel hardware has around a 100,000 lb. tensile strength and I'd never use it in any metal to metal connection that has stress. A grade 5 common steel bolt (metric 8.8)has 125,000, a grade 8 (metric 10.9) around 150,000 and a grade 9 around 180,000 PSI. The star-drive heads hold up better under high torque then then the square. I assume that is why star drive in getting more popular in construction. The only slight disadvantage to star drive is the bit has to be perfectly in the same plane as the screw. Not so easy all the time in construction. Square drive allows a slight angle and Phillips even more. Phillips was once preferred in some sorts of power driven assembly because the driver-bit could "torque out" instead of snapping the end of the screw off. Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 Some screw head types here. When I first started working on RVs and house trailers - clutch-head screws and square drive were common. I don't see clutch-head being used in newer stuff. Back on the subject of the general term "stainless", most SS screws used in wood are type 18-8 and sometimes 316. Both low strength (less then a common grade 5 for steel). If someone wants stainless steel for fasten parts that require strength - A286 or 17-4 PH are the ones I see most commonly used. Often twice the price of the weaker stainless and about they have strength to a common steel fastener in between grade 5 and grade 8. If someone is re-doing their RV and using any treated lumber- stainless steel hardware is almost a "must." Hot dip galv 2nd (not electroplate). Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 26, 2013 Share Posted January 26, 2013 Favorites! Quote Link to comment Share on other sites More sharing options...
fred heath Posted January 26, 2013 Share Posted January 26, 2013 JD: TMI...... Karin said "weak" I said "soft". Didn't know we were splitting hairs here. I can't provide specs and pictures as you do. I do a lot of home improvement work. I prefer to use ss "trim head" screws to attach Azek trim boards. They are #2 square drive. Unless you want to predrill all your holes,you depend on the torque of the drill to drive the screw. ss screws tend to round over. Steel screws not at all. This is an observation made by me over time. I introduced it into this thread as an FYI. I am by no means an authority on ss screws. On a brighter note, how do you like this "cold snap" we're having? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 26, 2013 Share Posted January 26, 2013 On a brighter note, how do you like this "cold snap" we're having? 'Brass Monkeys' weather. Now that I got the old John Deere 'blower working again (14 cent cotter pin), we're expecting a 'heat wave (40F & rain) on Tuesday. Better get the lawn mower fixed! Quote Link to comment Share on other sites More sharing options...
zero Posted January 26, 2013 Share Posted January 26, 2013 JD: TMI...... Karin said "weak" I said "soft". Didn't know we were splitting hairs here. I can't provide specs and pictures as you do. I do a lot of home improvement work. I prefer to use ss "trim head" screws to attach Azek trim boards. They are #2 square drive. Unless you want to predrill all your holes,you depend on the torque of the drill to drive the screw. ss screws tend to round over. Steel screws not at all. This is an observation made by me over time. I introduced it into this thread as an FYI. I am by no means an authority on ss screws. On a brighter note, how do you like this "cold snap" we're having? As to the cold - we're burning wood at twice the usual rate. Got down to 18 below F here. I tried to help out a friend of mine that has a saw mill-near Saranac Lake, NY. It had gotten down to 32 below 0 F and none of his diesel fuel would run. Every diesel powered machine he had was dead. This weather was common around here maybe 20 years ago but since then - we've gotten kind of spoiled with winter lows rarely getting below 0 F - until now. I was in the middle of painting and epoxying my work shop when the cold wave hit. I painted one night when the shop temp was up to 65 F. Came back in the morning and the paint never dried. Got too cold (was about 45 F in the shop). I turn the wood-fire down low when I'm not in there. This time I should of kept it stoked up. On the subject of square or star-drive decking screws. They are self-drilling - i.e. no predrilling needed. That have special ends that predrill so decking boards don't crack and don't have to be predrilled. I used decking screws in just about everything for two reasons. #1 they are high-tensile and near impossible to break, and #2 they are super rust and corrosion. They have to be due to the new chemical used in pressure treated wood that destroy plain steel or aluminum. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 26, 2013 Share Posted January 26, 2013 On our local TV weather maps, Saranac Lake and Sherbrooke are always the lowest temperatures in the Winter. Summer, too, possibly! Quote Link to comment Share on other sites More sharing options...
fred heath Posted January 26, 2013 Share Posted January 26, 2013 JD: How did we get from discussing the inherent weakness of stainless screws to deck screws?I totally agree with you on the use of deck screws.Hang in there, warm weather is coming. Quote Link to comment Share on other sites More sharing options...
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