Quill Spring 'Repair' - Tiger Tools 16" Drill Press

[baumgrenze]

My Tiger 16 drill press is blue. It does not have the smaller Hollywood Tools decal. In the 1970's my late neighbor. Mac, inherited it from his uncle, Bill (Wm Ordway,) who lived in southern California. Mac 'stored' it in my shop because he knew I would use it more than he would and he knew where it was if he needed it.

The quill return spring broke recently. My assessment is that it was repaired years ago by Bill. I'd like advice on the best way to drill and bend the rotating end of the spring.

1) Do I pull up the inner end of the spring and isolate it with a C-clamp and then draw the temper some by 'kissing' it with a propane torch flame?

2) How big a problem will it be to reinstall the spring once it is ready for reuse.

I will link a set of images and hope they survive long enough to allow comments. If others think they are worth downsizing to <164 KB I can do that and upload them to the website.

http://imgur.com/a/T21oG

http://imgur.com/a/XqJgf

Below are my comments on each of the images:

IMG_4414-16_Composite_TigerToolsDrill Press_A590.jpg

This is an overall image from the left face and the working face of the drill press. The right side is photographically inaccessible.

IMG_5752.JPG

You can see the break in the spring at around 8:00. The fixed end appears to be held down at around 5:30. I believe I need to remove this longer piece of spring and carefully bend the broken end towards the center shaft. This appears to be the first step in boring a hole for the pin that engages the spring at the moving end, near the shaft. What precautions need to be taken to avoid weakening the spring where it is bent?

There are six detents in the well that engage the inner face of the cover plate and anchor that plate in place maintaining tension on the return spring.

I remeasured the spring; it is 2.85" OD and 2.35" ID. The feed lever makes about 1.5 revolutions to reach full extension of the quill, so 12-13" of the spring is wound towards the central shaft as the quill is lowered to its maximum travel.

IMG_5753.JPG

This image shows inside of the quill spring well cover and details the short end of the broken quill return spring. Both ends are rough, indicative of a previous break. The 1/4-20 Allen screw (pointing downward in the image) which retains the rotating end of the return spring is inserted into a 1/4" hole that is 1/2" in from the rotating end of the spring. The threaded hole that retains the screw is tapped approximately half-way into the shaft collar which allows it to be driven in tightly. Both ends of the remaining fragment of the spring show rough breaks, suggesting that it broke before.

The outer diameter of the Allen screw fits more snugly into a 0.246" diameter hole made by a letter D drill. The above spring fragment has a 0.25" hole. Would a smaller hole or a 1/4-20 keeper nut improve the assembly or is it overkill.

The protuberance at 9:00 engages with one of the six detents in the spring well cast into the main drill press casting. The plate engages the quill feed shaft via an external 1/4-20 Allen screw. The Allen screw serves to retain the return spring tension by holding this plate so that the protuberance is engaged and also by engaging the feed shaft.

IMG_5754.JPG

This image shows the outer face of the quill return spring cover plate. The plate fits between two 1/4-20 Allen screws set into a collar that fits the shaft. Between the collar and the plate there is a large, thin spring washer. The central portion turns freely inside this plate.

The spring is tightened by using a Crescent wrench on the flats of the collar so that the quill to the top of its travel when the feed lever is returned to its resting position.

\IMG_5755.JPG

This image shows the most recent quill return spring break on the left and a perhaps earlier break on the right. The 1/4" hole engages a 1/4-20 Allen screw which is the attachment point for the moving end of the spring.

The spring is 0.505" wide and 0.036" thick. The wound outer diameter is 2.75" suggesting an approximate working length of 45".

The fragment is ~3.5" long. It seems to have the same temper as the rest of the spring.

thanks
baumgrenze

 

[Provincial]

I can only see the oveall photos of the drill press.

I wonder if the reason the spring breaks is that the 1/4-20 screw puts it in a bind if tightened, causing the spring to flex in a concentrated area instead of wrapping around evenly.

Ideally, the spring should have a uniform temper the whole length, because the untempered area will be more likely to fatigue and break.

If you research "Making a Clock Spring" on the internet, this site comes up first: http://www.m-p.co.uk/mp-spring-guide.htm It is British, and references several British steel standards, but has a good description of how to make a spring. This search brings up many other sites that could prove useful.

I expect that you will be better off making a new spring if you can match the material dimensions of the old spring. No years of fatigue and you can make it the original length. The above search seems to indicate that winding a new spring is not real difficult.

Good luck! It sounds like an interesting project. I have only wound compression coil springs, and it wasn't difficult at all.

 

[MShaw]

you can also go to a clock repair supplier like Timesavers in Scottsdale, Arizona. (timesavers.com) they have a large variety of springs at reasonable prices. ($9.00 to $30.00) All you need is the thickness, width and length of the old spring.

The temper is always drawn at the ends where the hole or other attaching method is. When reworking a spring I draw the temper by heating the end red with a torch and then SLOWLY withdrawing the flame so that the spring does not re-harden.

 

[baumgrenze]

Thank you both for your observations.

I just tried again. The "imgur.com/a/XqJgf" link is to a folder. If you scroll down there should be more images revealed.

I'm inclined to try to 'restore-to-service' the existing spring. At 77 it is not likely need to be called upon to serve me all that much longer. Also, in time out of mind, I had to rewind the return spring. I vaguely remember working out how to do it. Being young and vigorous I probably made it tighter than it needed to be and hastened its failure. This time it will be wound just tight enough to support the quill and perhaps a fly cutter. I don't need to end up with a broken wrist because it got hit by one of the 'Saturn balls' on the feed lever when the one I was holding slipped from my grasp.

Thanks,
baumgrenze

 

[baumgrenze]

Re: Quill Spring 'Repair' - Tiger Tools 16" Drill Press - More Wisdom?

This evening I had a few minutes and I grabbed the broken end of the spring in a small ViseGrip wrench and freed it from the well. I've attached a photo.

The pin at 6:00 that holds it in the well is tight. I could drive it out with a small drift punch, but why make work. The spring is long enough so that I believe I can mount it in my drill press vise and bore the needed hole.

I can grab it in a ViseGrip at around 3" and draw the temper with my torch. Does it need to be fully annealed or can I try to chase 'pale straw' to the ViseGrip jaws? Do I need to worry about air hardening?

I've shaped, then hardened and drawn the temper on some 1/8" drill rod grafting knives that are flattened hot at the bitter end, shaped to a chisel end, bent around half-circle to make a U, then hardened, polished, and had the temper drawn with a gently applied torch flame, following the colors.

http://wiki.dtonline.org/index.php/Heat_Treatment

I probably can't quench the end effectively, but I don't think I want to, either.

Does this approach make sense? I've had one Yes and one No. Is there more wisdom to be tapped?

Thanks
baumgrenze

 

[MShaw]

The springs that I have done in clock repair would be drawn completely(dark blue to black) and the flame withdrawn slowly to keep them as soft as possible. If the flame is removed quickly they will air harden and be brittle.

 

[baumgrenze]

Thank you, MShaw

I did not heat enough of the spring the first time and another 1.5" broke off when I tried to bend it. The second time I used some flame resistant ceramic wool batting for heat retention. I gripped the spring in a large ViseGrip wrench at about 3" from the end. With ceramic wool behind the spring I heated the 3" section with my torch to a dull red and quickly covered the exposed face with more ceramic wool and allowed the spring to cool to room temperature. It was still magnetic, but was annealed enough to drill and bend. I had to do the drilling with a hand held drill. I gave up trying to remove the pin at the larger or fixed end of the spring. The spring coil with one end fixed made it impossible to use a table vise and the drill press. The drilling went OK with the spring gripped in a ViseGrip clamped to the drill press table. I started with a double-ended center/countersink bit for stability, went to a sharp smaller drill bit, and finally used the letter D to finish the hole. I repacked the spring into the well and found that I needed to gently bend the last few inches inwards a bit more towards the shaft but not quite touching. I ran the quill to the top and locked it with the locking wheel Then I placed the cover/spring tightener over the spring so that the internal set screw entered the space between the moving end of the spring and the shaft and rotated the plate clockwise. The pin rode around on the surface of the spring and snapped into and engaged the hole. Then I tapped the cover with a dead blow hammer until it was seated and tightened the spring maybe a quarter turn and tightened the external Allen screw to lock it in place. Everything seems to be working as it should. We will see how long it lasts.

Should I make the effort to resize the images and upload them? I have concerns about the resolution of details. I believe I read that sooner or later Imgur will block access to the links.

Thanks again for all who participated for your interest and advice.

baumgrenze

 

[6PTsocket]

Just a thought. There are a lot of quill springs on ebay and elsewhere. Maybe you could adapt something with minimal fabrication. They seem to be not that expensive for experimenting.

Sent from my SM-G900V using Tapatalk

 

[baumgrenze]

Re: Quill Spring 'Repair' - Tiger Tools 16" Drill Press - Sad News

Thanks for all the input. I am back at start here. My repair broke after about 10 uses right across the diameter of the 1/4" hole I drilled to attach the moving end of the spring.

Clearly temper here is critical. Perhaps spring tension is also significant. When I reinstalled the spring I was careful to tighten the coil only enough to balance the downward force of the quill mechanism. Perhaps I should have added a bit more tension to keep everything tight and in alignment at the top of the quill range of movement.

Thanks again for your encouraging ideas.

baumgrenze

 

[Vintage Veloce]

baumgrenze,
I just broke the spring on my Tiger, during reassembly after restoration. I foolishly turned the adjuster backwards, folding the spring on itself... oops.
At any rate, without even disconnecting the spring from the drill press head, I managed to drill a new quarter inch hole in the end of the spring with a cordless drill. I started the hole with a small cobalt bit just going enough to mark the center, and then drilled the rest of the way with a cobalt quarter inch bit. I drilled VERY slowly and was careful not to let the spring get at all warm.
The new hole is too big to hold on the spring, I suspect that is why the original spring has a crimp in it right at the hole, to hold the spring tightly to the set screw. Did yours break along that crease? Maybe that is the problem. Instead, I just bought a new round head 1/4"-20 machine screw and shortened it to the proper length.
I also note the spring had some slight bends near the end forming the initial curve: mine was like this as I received it. You can see these in the picture.
View media item 77710
This seems to be working fine so far. I've probably operated in 50 times this afternoon. Since the spring wasn't heated during the drilling at all, I expect it will hold up.