Repair Parts for Kobra Sights

Hey folks,

I am looking for repair parts for my Kobra that broke. The power switch broke/sheared off I tried to turn it on. I searched the posts, and they all seem to be about a year or two old. I tried contacting Tantal and Kalinka Optics. Kalinka, where I bought the scope, could not get parts. I have not heard from Tantal yet (Sent an email about a week ago). Anyone on the board have any ideas?

Thanks,

Qbeam

tantal has been having e-mail problems. his reply will probably contain an apology. use the sbcglobal.net address.

Heard from Tantal, and no luck on parts. He said he was trying to get repair parts. I told him that I would be in the market for 3 sets, and hope he gets the parts soon. We'll keep you posted.

Hey folks,

Well, I have decided to try two methods.

The first method is to make a casting of the part (repaired the stem, but it won't take the torsional stress). Will try to cast it with various materials (epoxy, JB Weld, epoxy with metal filings, polyurethane, etc..).

The second method is to machine it from round bar stock. I have access to a machine shop and the guys I work with are interested in this little project. So we will try our hand at it.

Hopefully one of the methods (or both) will be productive in producing a temporary fix until OEM parts become available.

Will keep you posted.

Qbeam

P.S. Let me know if you would be interested in getting a replacement part. Once I get a good prototype, I'll get a batch made. If it works out, I'll work out a price based on time and materials. I'm trying to keep it below $20 with postage. If I can, I'll try to Karma it.

I had the same thing happen and would be interested in the repair part if it works out. Let me know. Good luck.

Hey folks,

Update on the part fabrication:

Machining the part is proving difficult. Molding the part hasn't begun yet (this will be the last resort).

I have also tried to fabricate the part from two washers soldered together and will dremmel the washers to fit. A square rod will be soldered into place and hopefully work as advertised.

Will keep you posted.

Thanks,

Qbeam

Hey Folks,

Here is the latetst:

I have finally gotten the fabricated part to work (It looks like the original part, but is ugly due to it being the prototype). It required the following from the local hardware store (I'll get the actual washer sizes, but the below are approximations):

Components:

Fender Washer (3/4" diameter, w/hole that should just fit 1/8" square rod)
Flat Washer (curvature should mimic switch curvature, I think I used a 5/8 diameter)
Square Rod (1/8" square)
Solder (Silver or Silver Bearing)
2-64 Machine screw of various length (based on how rod soldering went)

Equipment:

Grinding Wheel (optional)
Drill Press (able to take Wire gauge bits)
Vise (to hold the square rod for drilling)
Dremel Tool (Grinding attachment and Cutting Wheel)
Soldering Iron
#50 Drill Bit
2-64 Tap (Taper or Plug)

The process in a nutshell is:

Solder (or JB weld) flat washer to fender washer, centered on fender washer hole.

Grind Edge off of fender washer up to flat washer (a grinding wheel comes in handy).

Using the broken switch, mark the profile the cutout portions on the flat washer (the flat washer will be the limit that you grind to).

Grind the washer to match the switch profile

Take the square rod, and cutoff about 1 inch, and drill with the #50 Drill bit.

Tap the hole with the 2-64 Tap

Solder the rod to the washer (there should be at least 5mm extending past the fender washer side of the piece and the angle of the rod should be pointing to the low part of the ramp profile).

If necessary, a new 2-64 Screw may be used to make up length if rod was soldered short (happened to me, but the longer screw fixed the problem)


This method seems to work. It has not been field tested, and I don't know how long it will hold, but if this part breaks, it's modular, so repairs can be made.

I am debating whether to make additional units for folks (liability reasons :big: ), but if you are in a bind, let me know.

Thanks,

Qbeam

If you have the AA version, You might think about buying an airsoft replica. I'm willing to bet some parts are interchangable - like the power switch.

http://www.apextacpro.com/product_info.php?cPath=34_24&products_id=625&osCsid=1c7f8e0265ede11919d3d785df445461