Screw Source for C-403

[tonyowen]

For what it is worth the screws on my CC400 are all imperial sizes (inch based) albeit some metric screws thread are very close to imperial and if you are lucky interchangeable
.
regards

Tony

[Harold_4074]

Jim Jones probably has the best answer. I just took a look at one of my CC-400 cameras, and it looks just like yours---except that the head of the screw is close to flush with the face of the lever. If you are careful not to lose anything and take note of what goes where, you should be able to disassemble the faulty release lever and inspect it to see if the part which engages the screw head is bent outward. If necessary, you can also disassemble the other release mechanism and compare the parts. A guess would be that the screws are original, but the lever has been bent.

[Jon Shiu]

He is missing a bolt. He has only 3 out of the 4 total.

Jon

[Harold_4074]

Yup. Its right there in the first line. Seeing the picture I had understood that he was looking for a replacement for a replaced, but non-functional, screw. Darn.

But the head of a 4-40 fillister head or socket head screw should be about 0.183 diameter, so chucking one in an electric drill and taking a file to it should solve the problem fairly easily.

[Steven Pituch]

Thanks everyone for the advice. Yes, I've been to the Ace Hardware store and Home Depot, but I really didn't know what to look for. I will go back to Ace and look at their 4-40 screws. I have the following info now:
Top of threads: .108"
Unthreaded part of shaft: .076"
Height of head: .070"
Diameter of head: .143"
Approx pitch: 40 th/"

I was afraid I would need a lathe but using a drill and file is a good idea. I will post a progress report soon. If Ace doesn't have a decent cap head screw I will check out McMaster-Carr Supply.

Steve

[Leigh]

I was afraid I would need a lathe but using a drill and file is a good idea.

Your dimensions look good. The nominal thread diameter for #4 is 0.112", so your 0.106" is fine.

Socket-head capscrews are made from the hardest steel in common use, almost a hard as a file.
Turning down the head diameter would probably require a grinding process of some sort.

Of course, screws from certain Asian countries may not meet normal specs.

- Leigh

[tonyowen]

I took one of the relevant screws off my CC400 and found that a 2mm or 2.5mm or 3mm screw fitted the tapped hole. (I do not have a micrometer hence I'm not certain as to what sized screw I used). The original screw has either a shoulder or a plain portion to its shaft so that it does not clamp the lever tight when fully tightened. The metric screw I used had a nylok fitted so it could be screwed in, but not clamp the lever nor vibrate out.
regards
Tony

[Harold_4074]

I just went out to the garage and tried filing a couple of black-oxide finish socket head cap screws (a 2-56 and a 6-32) and a smooth mill file cut them just beautifully. However, YMMV.

With due regard for personal safety (eye protection, particularly, and no personal appendages in contact with sharp, hot, or moving objects) you should be able make a replacement screw yourself.

The procedure than I have used a number of times on screws this small or even smaller: run nuts onto a fairly long screw (at least half a inch or even more if possible) to give drill chuck jaws something to bear on other than the threads. Lock at least two nuts together, flats aligned; this may damage the threads, but will keep the screw from rotating and will be cut off later anyway. In decreasing order of preference, use a bench grinder, file, or belt sander to reduce the head diameter while the drill is spinning the screw. It takes a certain "touch" to keep the head round, but screws and nuts are cheap compared to cameras...

To cut the finished screw to length, the obvious tool (a hacksaw) is almost worthless unless you use something like a coupling nut (see McMaster-Carr, stock number 90264A410) and saw through both the screw and nut at the same time. My personal preference is a Dremel tool or the equivalent with a cutoff wheel; you can probably buy one at a Harbor Freight-type store for less than Calumet would have sold an authentic replacement screw. (If you go this route, use nuts run onto the screw and a vise or pair of locking pliers; the little thing will get pretty warm as you cut.)

If the hex nuts are wider than the screw head (they usually are, but there are exceptions) you can use the drill chuck as a vise: file, grind or sand the screw to length. Removing the nuts will straighten any burr on the threads but you will want to bevel the first thread (Dremel tool again, or an oilstone) so that it will start easily when you put it into the rail clamp.

tonyowen's comment about not clamping down the lever suggests that there may be variations out there, but my CC400 looks just like yours.Only the head is used for the pivot, so the screw should be short enough seat on the underside of the head.

Good luck!

[tonyowen]

[QUOTE=Harold_4074;1388665]To cut the finished screw to length, the obvious tool (a hacksaw) is almost worthless unless you use something like a coupling nut (see McMaster-Carr, stock number 90264A410) and saw through both the screw and nut at the same time./QUOTE]
Curiosity only, why cut through the screw and nut? The way I was taught (half a century ago) was to cut a slot through one of the flat faces of the nut. This means the nut can be clamped onto the screw thread when held in a vise OR use two nuts and lock them together. Then adjust the nut(s) so that the desired screw length is defined by the 'outside face' of the nut (or second nut). Cut against the face of this nut and file away burrs. Then undo the nut(s) which remedies any screw thread damage caused by the saw and file.

regards
Tony

[Harold_4074]

tonyowen:

Your question might appear to be afield from the original question but it is not, really; there is a matter of scale involved.

The screw in question is a 4-40, with a minor diameter of only about 0.080 inches. The reciprocal of this about 12, and to work well a saw blade should have at least three teeth engaged, so in theory a 36 teeth-per-inch sawblade would work unassisted. In practice, getting the blade down to the minor diameter in the first place is a challenge, because the corners of the teeth tend to hang up on the sides of the threads. Cutting through a wider piece of metal gets around this problem, and one or more nuts (typically 1/4 or 5/16 inch wide) is a simple solution.

Holding a 1/4 inch nut to slot it into a clamp requires a pretty decent vise, but if it can be held firmly a jeweler's saw with a fine pitch blade will cut both the clamp nut and the screw itself. But you can also run one nut all the way onto the screw, put a pair locked together with the inside face one saw kerf away from the intended length, and hold the locked nuts in order to cut along the inside face. One cut and you are done, and the first nut will de-burr the threads when you take it off.

I have a jeweler's saw and blades, but find that the fragility of the blades favors the electric drill technique unless I am cutting a brass screw and am willing to take the time to switch out the knurled vise jaws for smooth ones just to hold a 4-40 nut. When I "bolted" a lens retaining ring to a wooden lensboard with a Packard shutter on the backside, I did saw them off---there were (oddly) seven 2-56 brass screws to shorten, plus a couple of spares in case I lost one.

For larger screws and bolts (1/4 inch and up) I do exactly what you describe; keeping a few long screws on hand, shortening them as needed, saves having to drive to town every time something falls off of a piece of farm machinery!