Wolverine film advance and the jitters

[Bob Dunham]

Hi there! I'm having a problem with my Wolverine and jittery video. I've taken the machine apart to get a better understanding of the problem. I've tried the standard fixes of adjusting the pressure plate and eliminating the take up reel by letting the film drop into a box. No progress with those fixes.

The super 8 film seems to advance in a repeating pattern of 4 positions with the first frame advancing the furthest and the next 3 a little less.There is a small silver screw on the transport mechanism which raises and lowers with each frame. If I put downward pressure with the tip of a screw driver on this screw the jitters are minimized. I can fix the jitters with image stabilization but would rather eliminate them at the source.

The red arrow in the pics shows the location of the silver screw. Does anyone have any insight into this issue? Thanks!

[Dave Bickford]

My Wolverine trashed one film before running even 50 feet of film. And then it broke. I returned it. 🤷♂️

[Stan Jelavic]

We discussed this issue a awhile back in the forum Bob. I will have to get back to you because it was a while back. Here are a few causes off thee top of my head:
- Warped motor mount. One member reported this and had straighten out the bracket. What I recall is that there are 4 turns of the cam for one turn of the motor shaft. With warped bracket the motor gear is not engaging the cam gear consistently and will be repetitive by the count of four.
- Possibly worn out motor shaft mount so it has some play.
- worn out cam. I fixed this using the aluminum duct tape. Can dig out thee fix.
In any case I believe you will have to dismantle the whole cam mechanism. Not too hard but be careful with it. Several small delicate parts. I will try to send you more info.

[Bob Dunham]

Thanks for your help Stan. I did some digging in the forum and found some of the posts you are referring to. I took a look inside the gear box and noticed there is a fair bit of slop in the mechanism. I’m in the process of rigging a small spring arm that will put downward pressure on the silver screw. Looks promising so far.

[Stan Jelavic]

That is a good idea. At least to cut the jitter down to acceptable level.

[Thomas Dafnides]

Bob, How many feet approximately, did you run through the machine before you developed this jitter problem or was this on a new machine ?

[Bob Dunham]

Here's what I came up with to eliminate most of the jitters. The video is way smoother now. I used a small piece of stainless steel clamped in place to put downward pressure on the small screw. I gave the screw a few turns to raise it and put more pressure on the spring.

[Bob Dunham]

This machine is new. I've run about 400 feet through at this point.

[Stan Jelavic]

There was a very long discussion on the forum regarding the jitter that repeats every 4 frames.
https://8mmforum.film-tech.com/vbb/f...4484#post24484
Not sure if we ever fully resolved it but we suspected warped main stepper gear. Or something loose there.
The main gear to small cam gear ratio is 1:4. If the main gear is not perfectly straight it will drive the small gear unevenly causing uneven claw movement limits. You can observer the big gear motion and check if it is wobbling up and down.
The bent motor mount also can cause similar issues.
https://8mmforum.film-tech.com/vbb/f...fect#post30328