How to Secure Underside of Velmex Unislide

[joshmacro]

I just bought a couple of used Velmex Unislides. These need to be secured to parts of my rig (specifically to a block of wood). The unislides obviously have holes on the bottom with a countersunk hole facing the top (as shown with the red arrow below). But I cannot figure out how to get the screw through the hole since the drive shaft is in the way. Do I need to take this apart to get to these holes? Also, is there is known screw size that fits perfectly? Thanks!

[Chris S.]

Josh,

Yes, you should partially disassemble this UniSlide to get access to the mounting holes on the bottom. Fortunately, this is easy. On the opposite end of the stage from that shown in your picture is the "end block" (see diagram here. Two screws hold the end block. Remove these screws and pull the end block, bearing assembly, lead screw, and carriage, as one unit, out of the way. To reassemble, just reverse the process--nothing falls apart in any confusing way.

The mounting holes for small UniSlides are sized for #10 flat head screws (0.19" shaft outer diameter, but no one calls them that). I just now measured five of my small UniSlides to check, and also see this confirmed in the diagram referenced above. Larger UniSlides can have bigger mounting holes.

No. 10 screws are easy to find in the U.S. But in this use, I'd recommend you use stainless steel screws to avoid bimetallic corrosion, since your screws will be in contact with aluminum. Stainless may or may not be easy to find locally, depending on the size of your local hardware store. I've recently had an excellent experience sourcing stainless and other fasteners online from Monster Bolts.

--Chris S.

[RobertOToole]

I just bought a couple of used Velmex Unislides. These need to be secured to parts of my rig (specifically to a block of wood). The unislides obviously have holes on the bottom with a countersunk hole facing the top (as shown with the red arrow below). But I cannot figure out how to get the screw through the hole since the drive shaft is in the way. Do I need to take this apart to get to these holes? Also, is there is known screw size that fits perfectly? Thanks!
IMG_1415_resize.JPG

Good info from Chris already but I should add one thing.

All the unislides that I own, 1.5, 2.5 inch and 4 inch (at one point I owned at least a dozen of these things) all allow mounting and un-mounting with access to the mounting fasteners without taking anything apart, except, the 1.5 inch. The 1.5 inch you have to remove the end plate and slide the lead-screw etc out.

BTW I have extra 2.5 inch units if anyone is looking, even a 2.5 x 12 inch unit for horizontal or vertical movement.

One last note: you can add a Arca-Swiss style quick release clamp without drilling or modifying anything, see my site for more info:

https://www.closeuphotography.com/velmex-unislide

Best,

Robert

[joshmacro]

Thanks Chris and Robert. Unscrewed the end block per Chris' suggestion. Worked of course and now unislide is secure to my rig.