Mark VII Repair questions

[john_001]

Jacob Anderson has a video https://www.youtube.com/watch?v=YbHVTwSp9DI that covers the quill mechanism on a M5, and he shows attaching the spring, starting around 4:30.

[MichiganTom]

Jacob Anderson has a video https://www.youtube.com/watch?v=YbHVTwSp9DI that covers the quill mechanism on a M5, and he shows attaching the spring, starting around 4:30.

Thanks John!!

That video showed me what I needed, I'll just go ahead and put a new keyhole in the spring. All the bending I found on the end of the spring was
just damage.

That video also answered another question I had, based on the crud/wear marks on the pinion gears on the two shafts he used in the video, I could see that the Rack gear on the quill does not center completely on the pinion gear, so I'll just consider that normal on my machine.

Again thank you, this should be something I can complete with a few choice words included.

Regards,
Tom

[chapmanruss]

Tom,

Below is a picture of a relatively good Quill Return Spring from a Model 10ER. The narrow end of the keyhole is closest to the end of the spring. As John said the Quill Return Spring is the same for the Model 10's as it is for the Mark Series Headstocks today. I used a new, from Shopsmith, Quill Return Spring a few years ago in a Model 10 restoration.

_

102-28 Quill Return Spring.jpg (170.7 KiB) Viewed 637 times

.
Putting a new keyhole in the old spring will only "cost" you some time and effort. I have done that and it worked fine, just a bit of a pain to do.

[MichiganTom]

Thanks Russ,

I'm going to go ahead and put a new key slot into the spring, looks like fun. Don't know if I'll get to it tomorrow, but soon.

Tom

[JPG]

That "screw" is supposed to be proud so the spring keyhole will slip under it. The orientation of the 'keyhole" is such that tension pulls the spring under the "screw" head from the larger keyhole end towards the narrow thus capturing it. All this works unless one rotates the quill handle backwards. That is what caused the bending damage. The spring can be 'bent' as long as not too far. Bending that approximates the od of the quill handle shaft and that causes the spring to spiral in towards the middle(shaft axis) makes attaching the spring to the shaft easier(automatic if done correctly).

[MichiganTom]

That "screw" is supposed to be proud so the spring keyhole will slip under it. The orientation of the 'keyhole" is such that tension pulls the spring under the "screw" head from the larger keyhole end towards the narrow thus capturing it. All this works unless one rotates the quill handle backwards. That is what caused the bending damage. The spring can be 'bent' as long as not too far. Bending that approximates the od of the quill handle shaft and that causes the spring to spiral in towards the middle(shaft axis) makes attaching the spring to the shaft easier(automatic if done correctly).

Thanks JPG, that make sense. I'll probably get a chance to work on it tomorrow, I'll let you all know how it goes.

Tom

[MichiganTom]

Success!!

I was able to get the spring keyhole remade into the existing spring.

I removed the spring from the housing a spread it along the axes on a 1 inch wooden dowel and clamped it to provide a way to control the spring.
Then I lifted the interior end over the coil and it helped stabilize the spring in a position where I could drill. I took the original broken off piece of the spring and straightened it out to get the dimensions for the keyhole.

Spring hold-3.jpg (23.12 KiB) Viewed 427 times

Spring hold.jpg (21.2 KiB) Viewed 427 times

The spring material wasn't very hard, a standard drill bit went through without issue, I did a test hole in the broken off section first.
I drilled out two holes at the same size as the minor diameter for the keyhole then drilled the larger diameter for the clearance hole. I used a small Dremel cutoff wheel to complete the slot. Caution when drilling the larger hole, take you time the spring material burrs easily.

holes for keyhole.jpg (19.6 KiB) Viewed 427 times

New keyhole-1.jpg (17.75 KiB) Viewed 427 times

Old and new keyholes-1.jpg (22.08 KiB) Viewed 427 times

To reinstall the spring into the housing, I put a small screw into the side of the 1 inch wooden dowel and hand wound the spring until the diameter was small enough to slide into the housing. That was a little dicey!! if the spring would have made its way loose. I ended up reinstalling the spring twice, because I didn't pay attention to the orientation the first time. ugg!!

Wood shaft screw1.jpg (29.19 KiB) Viewed 427 times

Spring reinstalled.jpg (37.6 KiB) Viewed 427 times

Next step is to get the spring to be relaxed at a smaller diameter, thinking a tee handle with a screw in the side and keep turning until the spring returns relaxed at a small diameter, as JPG recommended. that's tomorrow, need to cleanup the shaft for reinstallation first, some burrs and damage on the handle ends to touch up, cleaning and rust removal.

Thanks everyone for the help and recommendations,

Tom

[JPG]

You done good!

The relaxed position needs to be slightly past center.

A radius minimally larger than the shaft works good.

[MichiganTom]

You done good!

The relaxed position needs to be slightly past center.

A radius minimally larger than the shaft works good.

Not sure I understand.

The relaxed position slightly past, center of the spring housing or shaft hole??

Radius at the keyhole minimally larger than the shaft??

[MichiganTom]

Next question I have, is once the retractor shaft is reinstalled and before installing the quill, how many turns are recommended to tension/preload the spring??