Both are commonly available. I have a JD head that goes counterclockwise. My Ryobi and McCullough spin clockwise.

I find that you have to switch direction as the spin direction changes. If I normally move right to left with a clockwise head, I find that I have to move left to right with the counterclockwise head.

The Safety Manual for my Echo trimmer actually addresses this very issue. I didn't read it for a long time, because I figured it was nothing but stupid-stuff-required-by-lawyers. Well, I was wrong. The manual is online, and the link is below.

Basically, you tilt the trimmer in one direction or another, depending on which way it rotates. The side where the string is moving away from you should be lower. Then it'll hit the top of the weeds and throw them away from you.

Here is a link that might be useful: Echo trimmer safety manual

What Suburban said, you're best off just getting used to going from a different angle.

Straight shaft attachments rotate opposite of curvered shafts because on curved shaft the drive goes direct to the attachment. Straight shafts have a gear box which makes the final drive backwards from engine rotation.

I have been dealing with this same issue for a long time, too. Bought a straight shaft and got filthy. Bought a curved shaft and didn't. Cutting the opposite direction only helps a little with the straight shaft. With a curved shaft, you can cut both ways and not get pummelled with trimmings, but with the straight shaft you get messed up even going only one way, it has to do with how it is held in relation to your body (right hand on trigger). With the curved shaft, debris clears your body to your right if cut on that side, but because of the position of the head the straight shaft dumps in on you if you cut on the left side.

I talked to several of the manufacturers about this, and finally got to a couple of engineers at one of them. It would be simple to make the straight shaft rotate the same as a curved, you just move the worm gear setup to the other side, they said, but they are not allowed to make straight shafts that way, even though it is the preferred setup for trimming with line. The rotation is opposite on straight shafts because they can be used with metal blades, and the direction is as it is to assure any kickout is in the safest direction for the operator. They were all very aware of the debris on the operator problems and would very much like to have a "trim only" straight shaft that would rotate like a curved shaft.

As it turns out, I had a lot of trimming (2 acres-175 trees) to do this last weekend and found my Echo curved shaft to now be too short to reach under many of the now larger pine trees. (other than that it is a great trimmer). I broke out the old straight shaft to do the pines, which reached fine. I then got chewed out for coming in the house covered in clippings (which I was). I had forgotten how much difference in mess there was between the two setups.

I just got back from buying a new Stihl FS75 curved shaft trimmer (last one available-discontinued) that is nearly a foot longer than the Echo. Hopefully, now I can have the best of both words.

if you walk backwards and to your left,a straight shaft trimmer will really do some cuttin.after usin a straight shaft trimmer,i cant use a curved shaft.yes they do cover you in grass,but its a small price to pay for the smoother cut and extra speed of counter clockwise rotation.If you walk forward and to your right,the trimmer will throw the grass away from you.Walkin backwards and to your right works great around mulch beds and houses and such,as it throws the grass backwards and dont make a big mess in my wifes flowers or the new paint i put on the house last year. I even take the guards off my trimmers to let out a little more string,and they cut as smooth as any push mower.Plus the extra string length slows the RPMs just enough so that your string doesnt wear down every time it hits a rock or a twig or somethin.But ya gotta be careful,if ya take the guard off,wear safety glasses,which is a good idea with any trimmer,guard or not.

Wear rubber irrigator boots and you wont have to fret about all the crap on your shoes and lower pant legs.
Mike

Ya, what Mike said. My Wellington Muck Boots are great for this kind of work.

Actually I wear a "chain saw hat" AND safty glasses when string trimming. The "chain saw hat" is a hard hat with integrated face shield screen, and hearing protectors.

I tried an Echo SRM261T last night. I found I got dirty moving left to right instead of my usual right to left with my curve shaft but it was not as bad if I walked backward. That machine screamed and did such a great job with the heavier line in half the time, I figure getting a little grass on me is a small price to pay. I don't wear a tie doing yard work.

I understand the cutting on the opposite side of the head by moving the opposite direction, but that is not always possible. Anything (steps, fence post,etc) that you need to trim on the right side off has to be done with the "wrong" side of the head and will put the trimmings on your feet. With the clockwise rotation, you can trim on either side and go either direction without getting messed up. Just wish the made a straight shaft that would go clockwise.

I just got an Echo SRM-210i and can relate. My string trimming skills ain't worth crap. I guess its an acquired skill...

C'mon peoples! Common sense, logic says clockwise will not be cleaner off both sides then a counter clockwise. Not if everything else is equal. So what makes them not equal?

1. User is so use to the angle of attack with one he just can't get it right the other way.

2. Straight shafts tend to come with more powerful engines, heavier cutting line and or longer line extension. Straight shafts tend to be upgrade home user or commercial which is why for the preceeding.
Heavier line or longer extension backed by a more powerful engine is not equal to the curved shafts and what they toss about is not going to be equal.

3. Some straight shafts being aimed more at commercial users have smaller debris deflectors.

When judging what is being tossed back at you, you first have to be sure all these factors are equal before saying something silly.

As HAL the computer said, "It can only be attributable to human error. This sort of thing has cropped up before, and it has always been due to human error."

Lee Valley sells a clamp on shield for straight shaft trimmers, I think. I plan to get one some day, 'cause I get trimmings head to toe. I just got a face shield for the same purpose. A hard hat with hearing protection sounds just fine, too.
Norm

Nevada: You are missing one big factor that makes things not equal. When you trim, the trimmer is on your right side, regardless of which way it rotates. When you trim, the left side of the head is pretty much always pointed at you as you swing it across. The right side of the head puts the clippings to your right, no matter which way you go. I tried using a straight shaft (counter clockwise) unit on my left side, and it worked fine. No trimmings on me at all. The problem is that the muffler and the rest of the setup is not conducive to using it that way.

Walrus is right. The actual cutting is a mirror image between curved shaft and straight shaft.

The reason the machines rotate differently is that almost all engines are designed to rotate CW when view from the top end. Doesn't have to be this way, but that is how most engine manufacturers standardized. To rotate the other direction a new ignition system would be required.

Manufacturers prefer to standardize because the same engine is used on pruners, hedge trimmers, and other tools as well as weedeaters.

Lastly, the manufacturers in the professional market have a lot of customers expecting CCW rotation of the head with straight shaft machines. I can imagine the uproar if they suddenly started turning the other way. In fact, at least one manufacturer (Tanaka) makes a curved shaft that reverse rotates so it handles like their straight-shaft products. Because Tanaka makes their own ignition rather than using the very common REPCO/Phelan, they can build a reverse rotation economically. Stihl might do the same.

As for speaking to engineers, were they sales engineers? because they certainly weren't design engineers. Every straight shaft on the market uses straight cut bevel gears. Either you misunderstood or they were pulling your leg about worm gears. Probably thought you were a newby and were having fun with you.

I don't see how bevel or worm would make a difference, except in the abstract for detail. With bevels you would just move from the bottom to the top, or the other way around, to change direction. Perhaps they were, misguidedly, trying to be easier to understand, but the principle is the same.

I totally agree that the commercial guys would go nuts because they all would have to relearn how to trim.

But, the cutting action is not a mirror image. For it to be a mirror image, you would have to hold the trimmer with the motor directly in front of you. You don't do that, as you hold it to the right side. When I held the straight shaft on the left side (where it did not throw clippings on me), I created the mirror image you talk of, but that is not how it is done normally.

I like to edge with the trimmer vs just bush whacking and CW is where it's at. Walking backwards and left handed is for the birds. CW rotation is where it's at or put a massive cover to block the junk. I have an Echo SS and yes I have tried tilting and it's difficult to achieve a nice edge as you would with a CW rotation. If someone can identify the SS trimmers with CW rotation I would appreciated.