please review these mirror holders (pictures)

[Finale]

This one I got for knife edging:







This one for dichroic mirrors:








First time purchasing an optics holders so I need some advice. In my opinion one set screw and rotating the holder itself allows to steer the beam in two axis and I think that should be enough.
I don't understand why the second holder (for dichroics) has 4 screws.

I know there are some good holders that have the set screws on top somehow for easier calibration. besides that, do these holders miss something important? And why the 4 screws on the second holder?

[Eidetic]

Four screws on the bottom one to give X and Y adjustment. Sometimes, rotating the mount by hand is just too coarse.

[laserist]

With the knife edge you're trying to get two adjacent beams roughly spaced and pretty damn parallel. With the dicros you're trying to get two adjacent beams superimposed on the surface of the dicro and also in the far field - you need to get the position-er at the right position superimpose the beams at the dicro's surface and then adjust the x & y axes for the far field - since the axis of rotation of the position-er is going to move as you slide it in & out and since the axis of rotation is unlikely to be anywhere near the plane of the dicro - adjusting the position-er's gross position and rotation to get the beams superimposed becomes an exercise in frustration. Hence wanting x & y axis "fine" adjustment. I've never worked with these devices, but there's a reason that high end adjustable mounts are expensive.

[Finale]

Hence wanting x & y axis "fine" adjustment.

Did I understand from your post correctly that fine adjustment is more important for dichroic mirror mounts than knife edging mirror holders?

[laserist]

Yes, but I was trying to be nice - the real take away should be you don't always get what you pay for but you rarely get more. You really want a precision three screw x/y mount for dicros, a 2 screw precision x/y mount will work for knife edging. Standard machine screws might be precise enough with a much longer tangent baseline...

[kecked]

I've used everyone of those and they well lack ...everything. Dump them. Also buy one of the three screw versions before you commit. I have found that if the screw is sloppy its not going to work. The 40-80 pitch is real hard to tap right. Shake the screw with your finger. If you feel any motion its junk. The good thing about those mounts is once they are set it usually stays put. Make sure the laser is warm and up to temp when you align or it will drift on you. I prefer mm1s but they are big and expensive and they can drift. I however don't knife edge more then two at a time.

If yo uare handy I bet you could drill and tap what you have to modify them. Its just a hole, some oil, and some gentle twisting of the tap. the biggest mistake I make is not making sure the source diodes are well lined up in all axis with each other.

[Finale]

Since I have them already I'll just check if they suit my need or not and if not I'll get some from Vladimir or lasershowparts.