Sunday, January 3, 2016

Screwdriver for woodworkers

There is a bewildering variety of fasteners out there, some were introduced to "solve" a problem, which introduced another and, and...
Others were in an attempt to make dis-assembly or tampering more difficult (there is nothing foolproof) but as far as we are concerned with woodworking, there are only a few fasteners (screw types) to be concerned with.

THE SLOT OR COMMON SCREW

The Slot screw is probably the first one that came out.

The first ones had a blunt tip (pre 1837)
Later the gimlet pointy shape we are now familiar with is post 1848.
Approximate dates.

Since they were mostly hand made by a blacksmith, there was a lot of variations. Both in the thread and in the location and size of the slot. This variety of slot sizes may help explain why the tip of our common or slot screwdriver were flared in two directions: In width and in thickness, in an attempt to accommodate them all.

My Sargent No 40, 4 inch screwdriver

Unmarked example, typical of North American style of screwdrivers

Typical construction.
The blade was loose, so I took it apart to fixed it 
with some judiciously applied epoxy. 


This of course introduced two major problems:

Depending on the slot width and the thickness of the blade tip taper,
the driver is only engaging near the top of the slot, which means the all too familiar cam out and damaging of the slot walls.

Because there is essentially no registration for the tip to remain centered on the slot, it is also all too easy to slip out and damages the surrounding wood.
If you attempt to sink the screw head below the wood surface, that width taper is going to cause more problems.


The best way to avoid these damages and frustrations is of course to uses a properly fitted screwdriver and screw. The slot has parallel walls, you will have a much better fit if your screwdriver tip had too (no taper) and was sized correctly for the screw slot (in width and thickness)

That is why in woodworking, your best bet are a set of parallel tip screwdrivers.

An older English engineer screwdriver (parallel tip)
that one is also ratcheting and reversible, I love it.

A typical English set of cabinet maker screwdrivers,
Marples. Pic is from the Ebay auction that I won.

For some reasons I never understood, these typical English Cabinet maker set of screwdrivers are not cheap, commanding good price on the used market (supply & demand?)
The good news is that you can buy excellent parallel sides screwdrivers from Brownells and etc. Take a look at gunsmith suppliers.
One brand in particular which is now available from some woodworking supplies store are the Grace screwdrivers. I got mine from Lee-Valley.

Well worth the small investment if you are using slot screws for that period correct look. For everything else stick to Robertsons!!
Since being "discovered" by the woodworking community, Grace also now make specialized screwdrivers for handsaws.

My Grace saw screwdriver.

Of course we all know that numerous saws makers have been using split slot nuts for eons, and the only way to tighten properly without damages is to use the appropriate split slot screwdriver... Problem is there were no real standard, so you may required a few to handle all your saws.

Typical saw wrest with a split slot driver at the other end

Nice idea, except that in a ill attempt to accommodate a wide range of slots,
 they put a rather steep bevel on the end.

A much better fit is with using the correct fitting parallel blade screwdriver, available from most saw makers.

Such as this Lie-Nielsen No 2 to fit my LN dovetail saw.

But what about the older saws makers such as Disston and all?  The good news is that it is easy to make your own properly fitted split nut screwdriver armed with a file. I use a rat tail file to make them. How deep to make the slot? deep enough to clear the saw nut post with some room to spare.

There is nothing more injurious to a saw handle than to continued using it with a loose handle. It will caused the saw nuts hole to widen compounding the problems. That saw handle being made of wood is going to expand and contract with the humidity levels in your shop throughout the seasons. That in turn will cause the handle to loosen in time. Similar problem with wooden totes and handles on a plane.

Another specialized area for slot screwdriver is for handplanes.
If you ever struggle not to slip while tightening or removing the screw holding the blade and back iron (chip breaker etc) you gotta try this clever design from LV . Simply brilliant! It capture the screw head ensuring no slips. NO, it would not fit every plane iron screws out there, but it will for the majority of modern design (think Stanley, Record and etc)

Love this little plane iron screwdriver from LV

 There are of course other screws to adjust on your typical Stanley design planes, so a pair of dedicated screwdrivers that fit correctly your planes is a very good idea.

Set from Woodcraft. Made to fit their WoodRiver lines of planes.
NO it does not fit all my planes...


If you are intent on using a cordless screwdriver to fasten or loosen these slot screws (or any screws types for that matter), you better have a good fit between your driver bit and the screw head or you will damaged them in a hurry.

And finally, if using brass screws, it is always very wise to pre-drill and uses a steel screws first to tap in the threads BEFORE driving in your brass screw, or be prepared to cry over (or uses appropriate expletives:-) when you snap the head off.

And remember for everything else, you cannot beat the Robertson...

ROBERTSON

Incidentally, I have since discovered that the so called Square Drive screws in the USA are NOT true Robertson copies.
Only Robertson and its licensees makes Robertson screws and drivers, the others are generically called Square Drive and are made by several manufacturers and brands since the patents have expired on the Robertson.
The Square Drive is an American clone of the Canadian Robertson that has a square recess but not tapered and has very sharp corners.
Likely this difference was to avoid patent infringements. The patented Robertson driver has slight taper and slightly rounded corners

Correspondingly, there are two similar looking driver bits.  The two methods of fabrication are:
The machined one piece and the two pieces, which is a forged steel tip pressed fitted into a steel shaft.

Several companies each with their own select brand names produced Square Drive. ALL true Robertson power bits and insert bits are of the 2 pieces variety, they have NEVER produced the one piece machined bit design.

Robertson look alike, but it is NOT.
It is a Square Drive bit. To add to the confusion they are sometimes marketed
 as suitable for both Square drive and Robertson... SQ2 means Square Drive No 2, and R2 is supposed to means Robertson No 2, but beware.

The typical 2 piece end bits are Genuine Robertson and are often color coded

That revelation probably explain why I considered that Stanley Made in USA a P.O.S. It was designed for Square drive screws NOT Robertson.
If your driver says Made in USA it is made to fit Square Drive screws

Of course this now is creating a problem here in Canada, since with the arrival of the giant US retaillers Home Depot and Lowes, they are no doubt introducing these inferiors Square Drives screws and drivers unto an unsuspecting public.
They somewhat look alike, but they are not upon close inspection.

PHILLIPS

Now if you think that this is all confusing, ever experienced the joy of stripping a Phillips screw?
Easy to do since there is a variety of similar looking but slightly different types.
Uses the wrong one and you will damages the screw, the driver or both...

Phillips, Reed & Prince, Frearson, Pozidriv (as often found on European hinges)
and if you ever work on consumer electronics, you ran into the slightly different Japanese Phillips imitation: JIS B 1012.

BUT if you enjoy cursing and swearing in any language, then go ahead and use the same screwdriver on all these different types :-)

Bob, with a rather large collection of screwdrivers, and now you know why.
Choose your weapons wisely :-)







10 comments:

  1. Nice write up on screws Bob. I like that second no name screwdriver you fixed. The old drivers had a look that the plastic crap of today just can't match.
    Is there anything on torx or others to come?

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  2. Thanks mate
    Yes old fashion screwdrivers are pretty cool but they don't take up much torque. I wasn't planing on doing other types of screws, I just concentrated on the 3 most used in our daily woodworking.

    Bob, who cleaned the yard... for Rudy :-)

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  3. And before I forget... If you take a hard look at the first link, to Wikipedia, it has a pretty good write ups on all the types covered.
    And if you check some of the references listed on it, you'l get more than you want to know about fasteners... :-)
    All to say that I cannot see a need for me to cover the remainder unless ... I missed something?

    Bob, finishing the Egg Nogg :-)

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  4. Good stuff, Bob. Thanks for that. Before this post I thought Robertson and square drive were the same. The screws that came with the Kreg pockethole jig I bought several years ago (and rarely use now) were square drive. I liked them a lot for the positive hold between driver and screw.

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  5. Bob,

    Thanks for the quick and dirty on screws and drivers or is it turns.?

    You should have a couple of 100 lb. dog food to poop converters :-). Fifty lb. bag in, near fifty lb. out, like clock work.

    ken

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  6. Hi Matt
    I long thought that Square drive and Robertson were the same thing, but they are not. Close but no cigar as they say.
    Here's the funny thing. Using a Square driver with a Robertson screw results in a floppy fitting, using a Robertson on a Square drive results in a tight interface but you run the risk of damaging the screw or the driver bit because the taper bit is jamming into the square opening and the screw entrance hole in the head is not slightly relieved as in a Robertson. For best results with both system stick to the correct driver/screws.

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  7. Hi Ken
    Screw driver or Turn screws? Both are correct :-)
    Yes, it never cease to amaze me how much the little guy can eat and "process"... I think ill pass on your idea, my poop converter is working just fine HaHa

    Bob, full of it :-)

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  8. Hi Bob,
    interesting write up. The Robertson screws are completely unusual here in Germany. And even slotted wood screws are meanwhile hard to get.
    Phillips screws are the standard nowadays which doesn't look good in fine furniture or boxes.

    Cheers,
    Stefan

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  9. Thanks for the feedback Stefan
    Since Pozidriv are the screws used on "European" hinges, are they not more common than just plain Phillips?

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  10. Oh well, you are right :-)
    For me they are cross sloted screws.
    But I have double checked it. And yes the Spax screws I'm usually using are of course Pozidriv. And also the screws on European hinges are PZ.
    Cheers,
    Stefan

    ReplyDelete