Paul C. Buff, Inc. Technical Forum

I recently purchased two PLM umbrellas from Paul C Buff. The optional setscrew is supposed to "keep the positioning shaft in place inside the umbrella while storing it between uses." I assume that the "positioning shaft" is the tubular 10mm shaft. Indeed, the setscrew is long enough to penetrate the hole in the positioning shaft, holding the shaft in place. So far, so good.

Unfortunately, I am using the umbrella with the 7mm shaft, mounting the umbrella in the conventional way, rather than using the speedring. How is the 7mm shaft held in place while storing the umbrella? And how do I keep the positioning shaft from sliding on the 7mm shaft when the umbrella is mounted?

If the setscrew were longer, it could be tightened to grip the 7mm shaft. But it is too short and just falls out when it is tightened too far. Should I simply use a longer setscrew? If so, what are the specs of the setscrew (pitch, threads per inch, etc.) If not, what is the correct way to store and mount the umbrella with the 7mm shaft?

First I must apologize for not answering sooner. I swear I typed a response, but it may not have taken, which can happen if the system times out.

You are correct that the set screw will not hold all three shafts, but it can be replaced with a longer 10-32 **Correction- it is 8-32** sized set screw.

The inner thumb screw can be used to hold all shafts and to the 7mm rod when opened to prevent sliding, however, it must be undone to collapse the umbrella. Without using a longer top set screw, the 7mm shaft will need to be stored separately from the umbrella portion.

Am I missing a part or mis-using my 8' PLM umbrellas?

I use two "old-style-mount" PLM's (8') that have the smaller-diameter shaft. When deployed, the shaft must run through the channel on the top of the Einstein heads. When I fold everything its shaft is short enough to disappear into the umbrella in its folded state. I have no other shaft that must be fitted for use with a head on a stand, right?

jonathan7007

For the purposes of ordering, we have two styles of umbrellas, which offer three mounting opitons, 8mm regular umbrella shaft mount as one, and the speedring mount, which also has a solid 7mm rod as the other.

If you have a fixed umbrella rod, then there is no other equipment to use, and no set screws to tighten. The PLM just opens and closes like a normal umbrella. All but the very first run of this style have center shafts that are short, so that the slider will come off the end of them when collapsed. The makes the shaft short so that it does not protrude far out of the back of the light when in use.

The speedring mount will have a fixed shaft, which then accepts the positioning shaft, which then accepts the speedring or 7mm rod. There is a set screw on top that can be adjusted to hold the position shaft, or can be replaced with a longer screw which can then be used to hold the 7mm rod as well. The speedring, if used, must be removed to collapse the PLM. It can be removed from the position shaft, if the position shaft is locked in, or the position shaft and speedring can be removed together.

My 51's use 8-32 set screws.

Indeed, you are correct. I reference the wrong item.