I finally located someone who sells "Apex" style JIS bits. Motion Pro, a motorcycle repair website, has the JIS bits. 2-packs of #1 and #2 are $3.50 each.

http://www.motionpro.com/product/08-0576
http://www.motionpro.com/product/08-0577

For whatever reason the Motion Pro #1 fits Fox 'phillips' screws perfectly!

Brett, you got that right! I found out trying to remove some head screws.

    I know for certain that there are two street/trail Suzuki 90s running around in the world with completely rounded-off "phillips head" screws, and marks from vice-grips around the outside.

    Another big issue, and particularly bad with model engine head bolts, is using a driver that is too small. The correct one (Phillips, JIS, even slotted) is the biggest one that can possibly fit. It usually looks ridiculous using a giant screwdriver on a tiny screw, but that's what it needs. Unfortunately, many times for head bolts, the right-sized driver won't fit in the head fins because the shaft is far too wide. They make electrical parts screwdrivers that are relatively narrow, but you might still have to grind them down on the outside edges to get them to fit.

   This was a big problem on the ST46 even with the slotted screws, because even the narrow electrical parts screwdriver of the correct size was about a factor of two too big. I eventually got a small cylindrical screwdriver and then greatly blunted the tip to get it the right width. I still keep that in the box with the ST parts. The Craftsman that fits in the head fins is probably 1/3 the thickness it needs to be.

   You shouldn't be able to rock it back and forth for any appreciable distance, if you can,  it is too sharp. With a proper fit, there is essentially no "slop", if you turn the handle, either the screw moves or the shaft twists.

   Get it to fit right and the screws themselves are fine, even the Fox screws.

     Brett

I know you don't like socket-head screws, but if you get good quality screws and good quality drivers then everything just fits -- you don't need to have a huge collection of nearly-the-same-sized screwdrivers just because of the huge plethora of "standard" sizes out there.

  I have nothing at all against socket-head screws. I merely disagree with someone taking a brand new engine and ritualistically discarding some of the parts - in this case, superior parts -  because they don't know to get the right $4 screwdriver. Or to cover virtually the entire range of modeling alternatives, 2 $4 screwdrivers (an JIS #1 and #2 pretty much cover the range of both JIS screws and Phillips for model engine applications).

    If you want exhume Mr. Garofali and berate his corpse for making the ST46 head fins too deep for the screw he chose, knock yourself out. I have the original slotted screws in my remaining 46, and all the others have 5-40 Socket Cap Screws from McMaster. 

    Brett

I get what Brett is saying in regards to a new and clean head but can't get past the fact that a used, oily and most probably gritty JIS head (or indeed any tapered fitting socket) needs to be in intimate face to face (as in fully home) contact to reduce 'camming' out under torque and the grunge prevents this a lot of the time.

A constant section tool like a hex key doesn't have the same exact needs.

I just purchased a JIS phillips on Ebay , works better than standard phillips on Enya 45 head screws, Anyone know where to get the
weird size Enya 45 head screws , and crankcase in socket head configuration

Walter, these guys carry a great supply of metric cap screws. http://rtlfasteners.com/

I saw too many of them with screws so buggered you had no chance of getting the head off without grinding the fins and slotting the screw head.
Dennis

Try drilling the head off screws, lifting the now undamaged head clear and then slotting the remaining shafts.

Much better than 'grinding the fins!'

Bill and Dennis thanks for the information.