Wolverine-Hawkeye Telecine

[David Brown]

Bruce
I agree with you about the set screw, and I had that happen back in November. In my case I had drilled out the set screw to 3mm and went a little past the shaft leaving a cavity behind it. It did distort the pulley. Maybe if the material surrounding the shaft is weaker than the set screw, it could collapse. A higher percentage of infill would be stronger.

The capstan_center_motor part has very little room for any play off axis. I have checked my motor shaft, it is not bent and the mounting screws are countersunk and flush.



Kamel
Does your new front panel have plenty of room above the circuit board? My camera now has 22mm of stand off. That will hopefully shrink with a different lens.

I thought of painting my toothed pulley with resin. The material is very textured and the teeth hang on to the perforations at times. I'm interested to see a resin print.

[Kamel Ikhlef]

David, I plan high enough because I plan to use a 16mm lens.
I have a a imaging source lens high quality low distortion that I would like to use.
I will be between 22 and 25mm high. And later, I would like to try in 4K.
So I plan space for a camera fan. I am still in the research and testing phase.

If you have any ideas, I'll be happy to design it (just a little hand drawing is enough).
For the pulley, my settings :
100% infill. shell: 2. speed 30 mm/s, layer: 0.05mm(0.1 min), bed: 80 °, nozzle temp: 230 °...
My software is Simplify 3D.

[Bruce Davis]

Thanks Kamel for the updated toothed pulley files.
David, the Capstan drive motor shaft is just too short for really good axial alignment with the printed plastics that we use, if the pulley is just pressed onto the shaft it runs true, if a little too much set screw pressure is applied the pulley wobbles (plastic flexes with pressure).

I also use S3D but always use 4 shells, one mistake perhaps is that I only use 30% infill, will try the 100%.

Looking forward to a better lens setup to utilise more of the sensor area.
Thanks all, regards - Bruce

EDIT Have given thought to inserting a brass tube say 3mm OD x 2mm ID to extend the length and area of the plastic being supported. The tube would have to be a press fit into the "Back_Pulley_Capstan".

[Stan Jelavic]

Got 4 good quality pulleys thanks to Bruce. Did some testing with them and noticed that the motor shaft is not at 90 degrees to the Wolverine panel. In my case this is caused by the motor mounting plate. The mounting screws are not flush with the mounting plate.

Tightening the screws helps but it causes the screws to hit the rotor. Replaced the screws with the shorter screws (M3x3):
https://www.amazon.com/gp/product/B075C6C4YR

That worked pretty well. Tightened the screws until the heads were flush with the plate surface.



This solved the wobble issue for me. I also noticed that the shaft hole is not consistent diameter. At the point where it touches the mounting plate it is snug but then it widens? That could cause the pulley to go crooked when the set screw is tightened.

Here is the picture illustrating the issue:

[Bruce Davis]

Stan, checked my motor shaft and it is reasonably square to the Wolverine metal panel, having said that the panel is not flat and has a slight bow in both vertical and horizontal directions.

The plastic material used does have flex when pressure is applied e.g. set screw, also the motor shaft is only 6.5mm long from the plate, the set screw applies pressure closer to the end of the shaft.

Trying to line up the pulley teeth with the S8 film Sprocket holes can be difficult, have measured from inner edge of film to the panel, the distance is 3.8mm for S8 and 3.4mm for N8. This would be 3.8 + 0.51 = 4.31mm and 3.4 + 0.91 = 4.31mm from the wall to the inner edge of the film sprocket hole.

Checking this was inspired by Davis's alignment problems, with the "Back Pulley Capstan" installed closer to the metal panel it will still work but the alignment is wrong. As one can see in the images above (if my calcs are correct) with the pulley in the correct location the set screw is right at the tip of the shaft.

The "Back Pulley Capstan" needs to be printed with a much "harder" material, not tough like e.g. PETG (Kamel might have some ideas).

Not sure if a motor with a longer shaft is available, that would also be good.

Next test will be inserting brass tube to extend the motor shaft bearing surface inside the plastic.

Regards - Bruce

P.S. I also found the best way (as David) to capture film without excessive jitter is to let the film roll up in a box on the floor. The good thing is the jitter can be removed in post processing.

[Kamel Ikhlef]

Based on your Bruce, Stan, and David experiences, I redesigned the back toothed pulley
with the locking hole shifted backwards. (just an new idea).
I don't have yet the idea what screw type to use.
If it works, I will post the new STEP file.

For the filaments. I ordered several samples loaded with metal (bronze, aluminum and brass) to test.
I'm waiting for them, otherwise the polycarbonate is very robust. there is also "metafil" (but very expensive).

[Stan Jelavic]

Definitely good ideas:
- different back pulley material
- extension tube
- change set screw location
Here are a few more:
- add another set screw from the opposite end
- put set screw at an angle hitting the shaft closer to the center

[David Brown]

Bruce Thanks for your hard work on this. I know it takes a lot of time. Measuring those tiny distances is even more challenging.

Another point on alignment, the film in the gate shifts closer to the face when using 8mm.

That can complicate all of this. I suggest moving the motor to the second position. This was discussed before to have the film gain more contact. The alignment of the film to the gate is not as critical when it is farther away, going under the pulley allows for better retention and eliminates the gate from pushing the film off the teeth. Yes, the motor's polarity must be reversed and by reducing the pressure in the gate using the folded paper or a permanent spacer allows the motor to pull the film from the second position.



Stan the shaft's hole in the pulley IS larger beyond the entrance. The support pulley can wiggle even when it seems tight.

With the motor mounted to the plate, but not on the face, I can space it off the surface and check for wobble. I have a drill motor chucked to the backside to watch it rotate. I was able to straighten the pulley and while holding it, tighten the set screw. It held the correction. I can't do that when it's mounted to the face.

The extended shaft is a good idea, the pulley is too close to the end. The new lock screw position could work as well.

[Kamel Ikhlef]

Here a idea compilation : double Fixation locking

[Stan Jelavic]

Bruce, can you recheck your calculation. I added 2 pcbs between the motor bracket and the back pulley.
https://photos.app.goo.gl/3yrXtkfhuTzyc7mbA
One pcb is for the Wolverine panel thickness and the other is to cover for the 1.39 mm cap between the back pulley and the Wolverine panel. I check the shaft depth through the set screw hole:
https://photos.app.goo.gl/am6diyRgDcPnZ3bm8
The shaft goes right through as you can see. The shaft length in my case is 0.35".

What is the shaft length of your motor? If it is 0.35" than we have a calculation problem.

[David Brown]

Kamel "double Fixation locking" is very deep. Took me a long time to place the new insert and I had to clean out the motor shaft's hole twice to monitor where I was.

It left a gopher's trail on the top and the bottom (a raised lump). I will try to file those down tomorrow. I'd rather file than do that again!

[Bruce Davis]

Hi Stan, I could make mistakes, double checked, please find images below, a bit hard holding vernier and phone, not sure if the capstan motor shaft lengths vary (I assume they should all be the same), or if there is a difference in the thickness of the printed mounting brackets, but my shaft as measured from the Wolverine metal support plate is 6.5mm long.
I have no idea where the differences lie. That extra 2.39mm would be good to have.

I do like your idea of set screws opposed at 180 degrees, will try it out to see if the wobble can be decreased by adjusting the tension on each set screw.
That's a great microscope.


Hi Kamel, thanks for your new ideas, not sure if having set screws at 90 or 120 degrees (as used in engineering) would help, as the pressure would still be applied to one side only (plastic side). As Stan suggested offset at 180 degrees might work because the pressure from one set screw would be applied to the second set screw, not the plastic. One would have to apply pressure to each set screw very carefully, little bit by little bit to ensure no pressure (or very little) is placed on the plastic bore. The plastic bore would be used simply as a means to keep the "Back Pulley Capstan" aligned with the axis of the motor shaft.

Hi David, "Another point on alignment, the film in the gate shifts closer to the face when using 8mm" yes it moves approx. 0.4mm, the inner edge of the film sprocket hole remains at the same distance from the support wall at 4.31mm.
I agree that more distance from the gate assy. would make this alignment less critical, but Stan would perhaps be the better judge as to whether it should be relocated.

The other thing I have noticed, due to there being a gap between the gate guide width and the film width, as the capstan has some influence on film sideways location (being alignment or wobble) each frame or after a few frames the film moves sideways adding to the jitter effect (this does not happen as much, actually very little if the film drops into a box on the floor).

Regards - Bruce

[David Brown]

Kamel "double Fixation locking" is very deep. Took me a long time to place the new insert and I had to clean out the motor shaft's hole twice to monitor where I was.

It left a gopher's trail on the top and the bottom (a raised lump). I will try to file those down tomorrow. I'd rather file than do that again!

Should have waited on the text. Might not have been clear. I'd suggest moving the second screw up, have one hole all the way through.



Stan / Bruce The shaft in the motor, you may have noticed, can move in and out some. The encoder magnet can move on the shaft and if pushed down, will hold the shaft back to appear shorter on the pulley side.

[Kamel Ikhlef]

Bruce, I have the same measurements as Stan.
In my opinion it is the printed support which supports the motor...
(are you sure that the screws which fix the motor are really flush with the plastic of the printed support).
They must not be exceeded to have the maximum of the axis outside the front panel (I have 7.75mm from the metal panel.).

David I don't understand what you would like. specify me that I can redo the design.

Stan, V11 validated?

BTW: I also have a lot of jitter problems !...
(in my opinion it is one of the biggest problem of this telecine and dropping the film in a basket is not a solution!
I had already mentioned this concern. maybe trying a winding desynchronization (for example windig up every 10 or 25 scanned images), but Stan is much more competent than me on this subject.

[Stan Jelavic]

The V11 tests are in progress Kamel:
- Power cct validated
- Motor control and speed control validated
- Rewind forward and reverse validated
Working on frame sync right now.
Next test with a test clip
Test capstan operation
Probably another day of work.

With the V11 the camera trigger is moved out to the return cycle and the jitter should be easier to control. I also believe I can sync the stepper with the rewind pulse which will make capstan operation smoother.