29K70/71 - Making my own parts

[Snakeoil]

As I mentioned in my first post about me new to me 29K70, the take-up lever adjuster was missing from the end of the piston. Plus, the piston turned out to be for a 29K71 machine. I suspect the change was an upgrade for the K71 as it provided a click adjustable range for the take-up lever where the K70 was a simple screw and lock nut. The actual Singer name for this assembly is Check Lever Thread Take-up Adjusting Screw with Indicator.

Nobody seemed to have those parts so with dismal weather outside, went down to the basement to make the parts from scratch.

I'm going to do my best to use the terms that Singer uses for these parts. Owning one of these machines is like learning a new language. There are photos below that use the same item numbers as the 29K71 Parts Diagram. The numbers are referenced in the write-up.

First order of business was determining the thread pitch for the female thread in the piston. Turns out it is a 5/16-28. No part of the Unified system so no taps in my machinist chest. Used a piece of 1/2" cold rolled steel to make the Indicator Body (14) and single pointed the thread on my lathe and using the piston as a thread gauge. Next was the Locknut for the Indicator Body (15).

Locknut was another single point thread operation. But at a minor thread diameter of 1/4" it required one tiny little threading tool. Ground one up and made the nut. Hex for the nut was cut on my little Altas horizontal mill.

The Adjusting Screw (11) was made from a 1/4"-28 bolt. I had to cut additional threads on the bolt shank. But being a UNF thread, this was a simple matter of running a die down the shank. With that done, turned the plunger portion of the Adjusting screw to 5/32", which is a size I arbitrarily chose. Left enough wall thickness for the 5/16"-28 Indicator Body thread and was beefy enough for the application, which is adjusting the position of the Take-up Lever. I think I am going to case-harden the end of the adjusting screw where it contacts the Check Lever.

Next was the Index Head (9) which was made from another piece of 1/2" cold rolled steel barstock. Knurled one end and then drilled and tapped 1/4"-28 to fit on the Adjusting Screw.

Last part was easy, the Lock Nut (8). Just took a standard 1/4"-28 nut and faced it down into a nice thin jam nut.

 

And before somebody pipes up and say that I left some parts out, I know. The tiny spring and plunger that provides a click stop type of adjustment for the Index Head has not been done yet. First order of business will be finding a tiny spring. I'm thinking an old spring from the flint in a cigarette lighter. The stop pin is also missing. I believe the stop pin allows only one revolution and butts up against the plunger in either direction. But my checking of the total travel of my Adjusting Screw relative to the amount of adjustment available for the Check Lever resulted in my set-up having 3 turns of range. So, I will probably not use the stop pin. I also have to cut the V-notches into the Index head for the plunger stop points and put indicator marks on the Index Head.

Here is the assembled Check Lever Thread Take-up Adjusting Screw with Indicator.

When this is done, next order of business will be restoring the stitch length to full spec. I suspect I'll be removing the head and either brazing or welding up the tab on the bell crank and then hand filing to spec of 5mm diameter.

I now understand why this was an upgrade to the later 29K machines. It gives the machine the ability to put a little more positive tug on the thread versus relying on just the spring pressure of the Check Lever Spring.

Regards,

Rob

Edited February 8, 2020 by Snakeoil

[mikesc]

Thank you for posting..
My kind of thread ( 'scuse the pun ) ..
:)

[Constabulary]

Excellent !!!

The "new type" regulators are hard to find so maybe you could make a few more.

Pretty sure sooner or later someone will need one of these. But not sure if it is worth your time.

[jimi]

Well done Rob, Parts look great. 

[Snakeoil]

Thanks for the kind words. The only way to make these parts economically would be on CNC equipment. I'd be more open to making one for someone in trade for similar services or parts. I make custom pieces for fellow shooters, mostly just because they are friends and have shared their experience with me to help me improve. I'm always surprised to have one of them hand me something for one of my rifles without me asking.

Jobs like this are my winter therapy. I'm not one to read the paper or sit on the couch and watch the boob tube. Blathering on forums like this (I really only participate in 3) is probably my only vice where I'm not really doing anything "productive". I always try to contribute, even if a newbie to the topic and this post was intended as a contribution, not self-indulgence, Facebook, lookit what I did, kinda thing. Although I have to admit, I'm normally proud of how things turn out so I guess there is a little "lookit what I did" mixed in there. I touch type (thank you high school typing) so I know I can get a bit wordy. But the goal is to be clear.

By the way, the damn hex I cut on the indicator body lock nut is not perfect. I tried to take too big a cut in the mill and the piece twisted in the collet. It cleaned up about 95%, but I still can see it and it bugs me. But the machine is not perfect so it kinda fits in.

Today, my search  begins for the tiny plunger spring I need. If I find one, I should be able to finish the assembly today.

Constabulary, can you confirm that the stop pin on the Index Heal only allows for one turn of the head? And do you happen to know the pitch of the adjusting screw thread. I'm not going to change it now, but am curious how close I got.

regards,

Rob

[mikesc]

Plunger spring..maybe in the heads ( behind the ball bearing ) of the "click on" square drive in busted ratchet wrench..? Singer appear to have made up many of their threads and pitches as they went along..even on the same machine.
There was someone posted here once ( he did not hang around ) that he had a full set of taps and dies for all Singers..even the old ones..But he never demonstrated that it was so, despite much interest from members..A set of those would be more valuable/ useful to some of us than unobtanium.

Don't apologise..great thread.. :) very interesting..

Constabulary, or Jimi, or shoepatcher may well know the pitch ..

Edited February 8, 2020 by mikesc

[Snakeoil]

Well knock me down and call me Nancy. I went down to my Dental Cabinet (not mine. Given to me by a friend from his days in dental school) where I keep lots of tiny parts, screws, etc., and found not one, but TWO tiny springs. No idea where they came from or  how long I've had them. Both were nearly the same OD. Short one (which I used) was 0.082" and long one was 0.084".

Drilled the Indicator Body with a #45 drill (0.089") and machined a plunger to 0.087". Rounded the end and polished. Then case hardened the end and repolished once hard. I still need to harden the Index Head. Although I doubt I'll ever move it enough to cause any measurable wear.

I don't have any tiny number stamp so I cannot mark the Index Head. I refuse to do it with a vibro-engraver. Maybe I'll just put hash marks on it. Afterall, if I cannot count up to 8, I probably should not be running machinery.

Here are some pics.

[dikman]

Like mike, I too enjoy reading posts like this. I'm impressed, that's some nice delicate machining, particularly cutting the threads!

[mikesc]

I don't have any tiny number stamp so I cannot mark the Index Head. I refuse to do it with a vibro-engraver.

Laser ?
500 dpi is average for the cheap to mid range ones..that can etch metal..the cheap ones ( diode , not CO2 * ) can do metal ( Alu..and sometimes some Steels ) if you paint the area that you want to etch first.

Dental cabinets, lathes..precision cutting tools, cnc gear ..you looking to adopt anyone :)..or visitors who'll cut the lawn , take out the trash, do dishes ..in exchange for use of your atelier ... :)

*the 2 in CO2 should be "subscript"..but I'm not logged in ( when I do login the "push" on site crashes my customised FF ) ..and I can't remember if J has the boards set up to allow the more "esoteric" stuff in HTML..Best not to anyway..restrict what can be posted is the best security.

Edited February 8, 2020 by mikesc

[Snakeoil]

Buying a laser engraver never crossed my mind. I took a look and they are not terribly expensive. I've considered making sights for vintage single shots and the limiting factor was the ability to engrave the windage and elevation markings. Might have to think about this a bit. Thanks for the poke.

[mikesc]

If you are going to do much steel..look at CO2 lasers ( a 40Watt unit will start at around $350.00 USD..check Aliexpress ) ..or at least 7.5 Watt and upwards in diode..15 Watt would be better.

[Evo160K]

On 2/8/2020 at 9:23 AM, mikesc said:

There was someone posted here once ( he did not hang around ) that he had a full set of taps and dies for all Singers..even the old ones..But he never demonstrated that it was so, despite much interest from members..A set of those would be more valuable/ useful to some of us than unobtanium.

 

If you're needing those special Singer taps, you can try Keystone Sewing Machine Co., Philadelphia, Pa, (215) 922-6900.  I bought the four tap sizes that LW member Shoepatcher suggested, they've taken care of my needs.  They didn't have dies at that time.

 

 

Snakeoil, I sure like your work!

[Snakeoil]

Nice set of taps. I would expect specialty taps like this to be available thru any of the major tap and die makers. But they probably would not make just one for you. You'd have to wait until they made a run of a particular size to buy just one or two.

The markings on the package just confirmed one of my suspicions. I measured the check lever spring screw thread the other day to make the stud and knurled adjusting nut and it was a tad bigger than an #8 screw. It measured 0.140" OD and a #8 is more like 0.136" OD. I would not expect a screw to be oversize. That's when I looked up at my decimal chart and saw that 0.140" is 9/64. So, I suspected that Singer used their own screw sizes as well as pitches and what I just measured was a 9/64"-40 screw. And now I look at your package of taps and there it sits. Now I understand why the test thread I made for the side thread tensioner stud was too small. I think I made that an 8-40. Will revisit that one soon.

Thanks for sharing your tap set.

regards,

Rob

[Snakeoil]

Finished the Check lever spring adjuster and stud.

Here is the spring adjustor and the Check Lever Thread Take-up Adjuster installed on the machine.

regards,

Rob

[Snakeoil]

Thought I'd share my light mount. I thought about mounting a tubular light in the OEM position. But then I remembered that Walmart sells these great LED desk lamps for about $6. I have one on my bench grinder. So I picked up another one and found a place to mount it on the machine. The base has a 1/2" hole drilled into it. It appears all the 29K machines have this hole. Suspect it is for accessing a bolt or screw under the base.

First job was removing the base from the lamp. Pretty easy. Also uncrimped the cheap, Made in China by prisoners, crimped connectors to disconnect the lead and switch from the lamp. I did not use the switch. The light simply comes on when I plug in the lead. I don't leave it plugged in when not in use.

Using a piece of  threaded lamp tubing , a few nuts, and a small right angle bracket I had in my odd metal box from a previous Go-Pro mount project, I mounted the light to that existing hole. I also had the aluminum spacer. But a stack of washers will work as well. Goosneck allows you to point the lamp to light whatever area you are working on, an of course to light up the needle area when sewing.

Here is a close-up of the bracket mount.

Used the original lead from the lamp, simply removed the base and switch. Terminated the lead to the lamp under the base and then taped the wire to the side of the base to avoid it rubbing on the shuttle driving lever and connecting shaft.

[Snakeoil]

Figured out the thread size for the side tensioner. Once again, the Singer education process plays a role. I'd thought it was a #10 screw with a different pitch thread. I estimated it to be a 36 thread. Too small ID to get a pitch gage on the thread. So, I cut a 10-36 test screw on the lathe and too big. Dropped it down to a 8-36 and too small. The 8-36 threaded in loosely, but stripped. I was thinking that somebody stripped the threads in the head and that's why the tensioner was missing.

Then I found that the thread for the Check lever spring tension stud was 9/64-36. Hmmm, if they used a unique size there, they could have used them anywhere. The story is longer, but I'm probably putting you to sleep by now.

I ended up turning a piece of wooden dowel to 11/64" and then forced it to thread into the tapped hole. Bingo. Gave me a nice impression of the thread. Put my pitch gage on it and it turned out to be 40 tpi. So, it looked like it was an 11/64"-40 thread.  I  checked that against the photo Evo160K posted of his Singer tap set and dang if there is not a 11/64"-40 tap in that set. Thanks again for posting that Evo

Turned an 11/64"-40 test screw on the lathe and fit like a glove.

Went thru my Machinery Handbook looking for that thread size. Nope. There are no thread sizes in 64ths listed in any size. This apparently was a Singer proprietary screw, like most of the other screws on the machine.

regards,

Rob

 

[mikesc]

I've often thought, that when it rained in Kilbowie ..( rainy climate ) they made up screw sizes and thread gauges, and shaft and pin diameters, bearing sizes etc..as a sort compendium of puzzles for engineers..

[dikman]

Snakeoil, welcome to the Wonderful World of Singer Screws! It took me a while to figure out that Singer screw threads are unique.

[Constabulary]

Excellent work! Very impressive!

Now you have to "invent" a 29K bell crank lever that never wears out and produces 6mm stitches...

[Snakeoil]

16 hours ago, Constabulary said:

Excellent work! Very impressive!

Now you have to "invent" a 29K bell crank lever that never wears out and produces 6mm stitches...

Thanks for the kind words.

Funny you should mention that. The other day, I took a plain piece of white paper and ran it thru the machine with no thread. It punched a nice row of holes damn near 5 SPI. Yet when I sew anything thicker than a sheet of paper, which is just about anything, best I can do is about 8 SPI. So, I'm wondering if part of the problem is slippage of the foot. I did sharpen the teeth on the foot with a small triangular stone. But then again, I suppose it could be that the paper offered zero resistance to moving and hence made it easier for a worn bell crank to produce 5 SPI.

I think I might pull the head off the machine tomorrow and get a closer look. Peering up into the bell crank area I see it swings on two screws. Play in those would also contribute to loss of stitch length.

I'm sure a redesign could produce a bell crank arrangement that would not wear. But it would require a major redesign to eliminate the rubbing surfaces of the crank and the ring and replace it with an adjustable pivot point similar to how the foot lift is adjusted.

I have a new Husqvarna machine that I bought for my wife and I'm the only one who has ever used it. I'm suddenly curious in how the stitch length is changed. It's under my desk. May just have to take a peak tomorrow. But I don't see me reinventing the 29K machines in the near future. After all, if it ain't broke...

regards,

Rob

[Constabulary]

You can adust the the foot lift on a small cam on the backside of the head. It´s marked H M L for High, Medium, and Low foot lift depending on the material thickness you want to sew.

The "official" stitch length for the 29K models range somewhere between 4.5mm and 5.1mm (I have seen both mentioned in official Singer documents). On the 29K model you have a pendulum effect - meaning the thicker the material the shorter the stitches - thats normal. So when you are close to 5 SPI on thin material that is a perfect result for a used patcher of this type!

EDIT:

BTW - seems you have used the front hole for mounting the lamp. This is a "tool hole" for adjusting the small timing eccentric. If it was my machine I´d put the lamp on the back side.

Edited February 13, 2020 by Constabulary

[Snakeoil]

Had not considered the pendulum effect and of course, this is a key variable in the stitch length equation. I'd like to think this would have finally dawned on me if I stared at the machine long enough. Thanks for short circuiting my slow thought process.

I discovered another factor that might come in to play from time to time. I took a thicker piece of cardboard and ran it thru the machine. It would feed fine and not feed fine. If I pushed it or pulled it, all was well. But it would stop every so often. What I found was that the needle upset the backside of the cardboard enough that it was apparently getting pushed into the needle hole on the needle plate and in essence, getting a "grip" on the plate. Have not seen that happen with leather or cloth. But some leathers might do this. I made a case the other day for a spotting scope lens from a cardboard tube. The bottom side of the cardboard had felt plus being curved, the area at the needle hole was raised off the plate a bit. But if I were covering a flat cardboard based case with something, I could see this happening.

Yeah, I figured that hole was there for a purpose. I also considered mounting the lamp on the back. Every other machine I've seen has the lamp mounted on the back in some fashion. I did not want to drill the base. I hate modifying original equipment. The hole was there, convenient and expedient. I may search the machine for another mounting point. What I like about it on the front is it lets me light the bobbin winding process. I have the machine squirreled away in a spot in the basement. I probably should just put an LED shop lamp over the machine and brighten up the entire area.

[plasmaguy]

Beautiful work !!!

[Wizcrafts]

39 minutes ago, Snakeoil said:

Had not considered the pendulum effect and of course, this is a key variable in the stitch length equation.

All sewing machines whose needle bars pivot on top experience the pendulum effect of loss of stitch length at increased thicknesses. In the case of a top feed only machine you can reduce the foot pressure to the minimum needed to hold down the leather to get the best feed.

Patchers use a feed motion bell crank that has a puck shape on the end that rides inside a ring to move the foot. This puck always wears out before the rest of the moving parts. As the puck wears, the stitch length decreases. It is easy to determine how much/badly your bell crank is worn by lifting the foot with the lift lever then push and pull the foot to test for slack. I usually do this with the stitch regulator all the way down against the top of the raised foot. If your crank has a 16th of an inch slack, the maximum stitch length would be around 8 to the inch. On a new machine it would get 5 to the inch at about 6 ounces thickness. A really tight fitting bell crank and ring might even continue getting 5 to the inch at 10 ounces.

[Snakeoil]

Thanks Wiz. Purely by coincidence, I happened to be reading the specs at the front of the 29K71,72,73 machine from the Shoe Systems Plus website. It appears that this is a manual published by Singer.

The specs for those machines, which I would expect to be the same as the K70 since they use the same bell crank, shows the stitch length as 7 to 15 SPI. I wonder if Singer decided to move to a more realistic number.

regards,

Rob