Fixit Log

Fixing and making things, what tools to get and what skills to learn, ...
User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

Yeah, depends on the quality of the OE tensioner. I had a Saturn in 94 with a crusty tensioner bearing when I pulled the first belt. They used a cheap bearing. It only lasted to the first belt. It would have failed soon after. Really depends on component quality.

davtheram12
Posts: 230
Joined: Mon May 28, 2018 6:02 pm

Re: Fixit Log

Post by davtheram12 »

@Gilberto de Piento
What Sclass said was accurate. Bearing wear is largely dependent on quality of the component and sometimes driving conditions. If it gave people better piece of mind I would recommend changing the belt tensioner and idler pulley but only with OEM components (provided they were made with quality materials to begin with). I've gone a little too cheap with some parts in the past and had to replace them after they failed or began showing signs of premature wear.

Gilberto de Piento
Posts: 1942
Joined: Tue Nov 12, 2013 10:23 pm

Re: Fixit Log

Post by Gilberto de Piento »

I've had the same problem. Don't buy the cheapest brake rotors and pads.

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

@Sclass So it's time for the first repair on our Elna 72 TSP (72C). I disassembled the machine enough to determine that, as guessed, the hook drive gear that turns the bobbin from below has broken. It's actually had all the teeth ground off. I'm wondering if the bobbin somehow got stuck and it broke that way or if the plastic degraded. The bobbin holder mechanism appears to turn okay.

I found this replacement gear:

https://www.ebay.com/itm/ELNA-SEWING-MA ... 0428379164

The original is black but all the replacements seem to be this white color. It's on Amazon too and one of the reviews gave it 1 star for being lower quality than original and returned it (sounds like they didn't actually try it).

Any thoughts on:

- why it broke or how to avoid breaking the replacement
- which replacement to get

Thanks! Oh, and I can take some photos if that is helpful. The way the chips from the original gear are on the bottom of the machine makes me wonder if it was some sort of mechanical lock up that caused it to go. It might have been user error on our part (so don't hold back if you think it's that!).

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

On the car parts, I really debated the different levels of quality/price for brake rotor and pads on RockAuto for our big SUV when I did a big maintenance push last year. I ended up going for a 2/3 to 3/4 up the price chart set[*] of the normal range (not the super expensive fancy stuff). Overall, happy but only around 5-6k miles on them so far. I did go with ceramic or semi-ceramic so every time we back out of the drive and apply the brakes for the first time, there is a screech. But they are quiet otherwise and ceramic should mean less dust. Oh, and I did use synthetic caliper lube -- really went by the book this time -- on the brake pads and cleaned the slides but still bit of noise. I think it's just the ceramics heating up.

* I went with Centric posi-quiet ceramic pads and Centric rotors. Cost about $270 for all 4 corners (pads + rotors, pads came with hardware kit, bought caliper lube separately)
Last edited by SavingWithBabies on Thu Apr 23, 2020 5:55 pm, edited 1 time in total.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

SavingWithBabies wrote:
Wed Apr 22, 2020 1:07 pm
Any thoughts on:

- why it broke or how to avoid breaking the replacement
- which replacement to get

Thanks! Oh, and I can take some photos if that is helpful. The way the chips from the original gear are on the bottom of the machine makes me wonder if it was some sort of mechanical lock up that caused it to go. It might have been user error on our part (so don't hold back if you think it's that!).
Hey, sorry I didn’t notice this post earlier. Ive been obsessed with Covid 19 lately.

That gear breaks because plastic in the 1970s wasn’t very good. Then if the owner used a petroleum based oil that attacks the plastic it can get brittle and disintegrate. There is a possibility that the machine got jammed up and it was forced to move and thus stripped the gear. But, in my experience good Elna gears (new replacement ones) are strong enough to stall the tiny motor on these home consoles. I usually buy my Elna gears from eBay. I’m not sure which are the best. I think I’ve used that exact vendor though.

I think there are good videos for this gear swap. You may have to mark your shafts with a sharpie to maintain hook/needle timing if you don’t want to mix it all up. I believe I have the pdf service manuals for your machine kicking around in case you need to retime.

I like to use silicone grease on that gear. Since it is nylon, it really doesn’t need lubricant. But I like how the silicone quiets the machine down.

I really liked my ceramic pads I recently tried on one of my cars. Less wheel cleaning required. A little squeaky. My wife forced me to go back to the organic non squeak variants. Since I get the non squeak cheapos for free with the Autozone lifetime warranty I cannot complain. I’ve heard but not confirmed, that the Autozone ceramics are highly abrasive and go through rotors faster. Since the AZO rotors aren’t guaranteed for life it kind of cancels out the effect of free pads.

The cheapo AZO pads wear out very quickly. I get about 15k from a set on the front. I live on a big hill with a crazy grade. I get a little kick out of changing a set and getting free replacements.

For grease, I bought a tub of high temp moly disk break bearing grease when I was in college back in 1988. I still have half. It is really a good sticky bearing grease that can take a beating heatwise.

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

That makes sense about the gear. I'll get a replacement and swap it out. I have a copy of a PDF maintenance manual. I saw that part about the timing and it made sense. I'll look for videos on repairing it -- I was hoping to do it with the shaft still in the machine. I was mulling over how to drive out that "lock" pin without being too rough on it but that's the kind of thing videos are great for. I'll get it swapped out and use some silicone grease!

That makes sense about the pads and the lifetime guarantee. I kind of hate to have to do the job too often though but it seems like a good route to go. And I should find a tub of that grease next time -- I ended up with a little flat pack squeezy thing and it was just enough for one job at probably a ridiculously expensive price by weight but inexpensive as a one time purchase. I was kind of in a rush though but it is nicer to have the lifetime supply amounts of those kinds of things.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

Hey good luck with the gear fix. Let us know how it worked out. I think the key with the timing is to make some sharpie marks on the hook shuttle and the shuttle housing around it as well as a mark on the main drive shaft to the frame of the machine. That way if things wiggle around as you swap the gear you can make sure both pieces are back in the same position they were in when you took things apart. Undoubtedly the videos will show this.

enigmaT120
Posts: 1240
Joined: Thu Feb 12, 2015 2:14 pm
Location: Falls City, OR

Re: Fixit Log

Post by enigmaT120 »

Ugh I've had a terrible time changing the clutch in my '81 Toyota 4wd pickup. Back at it today.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

Think McFly Think!

Image

enigmaT120
Posts: 1240
Joined: Thu Feb 12, 2015 2:14 pm
Location: Falls City, OR

Re: Fixit Log

Post by enigmaT120 »

That one's newer than mine but it sure looks nice. Maybe nobody dropped a tree on it.

Mine is back together and works this time! Sheesh I'm retired and I still want a vacation. At least a long bike ride this week. Today I'm going to reward myself by cutting trees down (Reepicheep can come help!).

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

I put the replacement gear into the sewing machine. Getting it onto the press fit shaft was quite a challenge. I didn't want to remove the parts from the sewing machine so it made it much harder. And the part was not sized correctly -- I sanded it down enough to get a good (and still very tight) fit. Unfortunately, I still can't get the sewing machine bobin thread to pick up by the upper needle. We need to get a new needle and try the basic steps first but not sure what went wrong. Probably need to verify the timing too. I am wondering if the bobbin mechanism is damaged in some way but I haven't tried reading all of the PDF copy of the repair manual to get a better understanding of how it works. It is quite terse. But at least the gear is replaced.

horsewoman
Posts: 659
Joined: Fri Jun 07, 2019 4:11 am

Re: Fixit Log

Post by horsewoman »

Ah, the joys of sewing machine repair! After parking my fancy-schmancy Brother computer sewing machine in a dark cupboard for 2 years because I was so fed up with its antics, I felt it was time to tackle it again.

On to YouTube for tutorials where I found this funny guy:
https://www.youtube.com/channel/UCn4Dv2 ... aintenance

After doing the timing check in this video:
https://www.youtube.com/watch?v=ZsebAKZxmU0
(all was well with my machine in this regard) I figured my machine has a tension problem, or a problem with the bobbin case.

I also found out on YouTube that you have to be very careful when putting in drop-in bobbin cases, as not to damage them. I'm on my third bobbin case with this machine, so I was definitely doing something wrong in this regard!
https://www.youtube.com/watch?v=d9EjTJvEQZg

I very carefully put in the case and tested it with the hand wheel after every step (putting in the case, putting on the stitch plate, putting in the bobbin) to check for tangling of the tread. Turns out, not only needs the case to be perfectly aligned, it depends on the perfect fit of the stitch plate, too. A few millimetres off and the thread gets stuck, even though the screws go in easily. This is an amount of fussiness I'm not accustomed to with my industrial machine or my old mechanical Pfaffs! Phew!

At least the machine is sewing again without jamming or breaking the needle, but the zig-zag stitch is not pretty on the underside of the fabric. There is a tension problem, for sure. With drop-in bobbins you are not supposed to mess around with the bobbin tension, but since my bobbin case is slightly damaged already, I scratched off the seal of the screw and played around with it a while. I was able to get a better stitch but it is not perfect yet. So I ordered a new bobbin case today, to test if the scratched case is causing the wrong tension. The old one was badly scratched, and I was not able to get all scratches out with fine sand paper. I hope this bobbin case (#4!) is the last one I need to purchase, since I'm now aware that I was doing something wrong. I was happy to see that the price for a bobbin case dropped from €40 to €30 since the last time I had to order one.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

Ahh yes. Your new gear is the gear that drives the hook so it is possible you’re a shade out of time. Since it was the last thing you changed it is likely timing. Follow the timing instructions in your service manual. First do an inspection to see if it is indeed out of time. Then if necessary loosen the screws and do the adjustment.

One thing you can easily do is open things up so you can see the hook come around and “scrape” the cutout in the needle while hand cranking. Run a thread and a swatch of fabric. The hook should come around and just grab the loop of thread that is formed while the needle is retracting. This is a quick way to see if your hook is coming around too early or too late.

The catching of the thread is affected by needle bar height and hook timing. The needle’s groove has to be in the right place as the hook nearly scrapes it’s side. At the moment this is happening the needle is slightly retracting through the swatch of fabric which opens the loop up a little bit.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

Image

this is what you'll see if you take the top hatch off your Elna Supermatic. I took the dogs off so you could see the hook and needle easily.

Image

the hook rotates around in a clockwise direction. In this image, the needle is actually beginning to retract upwards. The hook's point is about 2mm above the eye of the needle. You can check your service manual to find the exact dimension. The relative positions of the hook point and the needle eye are critical to catching the loop of thread.

To see it best I would thread the machine and hand crank it using a swatch of fabric to see the thread actually getting caught. You need fabric to create thread friction in order to open the loop. That way you can see in slow motion if the thing is actually working.

Once you determine it is not working due to late or early hook arrival compared to my images, then you'll have to adjust. Needle bar height and hook angular position are the appropriate adjustments. Since you didn't really touch your needle bar, I suspect you'll have to loose a grub screw on the drive shaft connected to the gear you replaced, or loosen a grub screw on the hook, and adjust the angular position of the hook.

Good luck.

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

Ah! That is great. So many blurry Youtube videos that are describing the basics and I'm trying to see exactly what you took photos of. I think something is broken but I'll avoid jumping to conclusions and methodically check it (I'll be happy to find out I'm wrong if that is the case). Thanks so much for posting the photos and describing.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

No problem. I took photos of the view looking down on the shuttle as if you’re sitting in front of the machine looking down on the needle plate. I have tipped up the bobbin access door and I’ve lifted out the needle plate. ( it just snaps out upwards). I have also removed the feed dog which comes out with two little screws. You don’t need to do this and if you do it without an offset screwdriver you can damage the screws. I just exposed the needle point and hook point so you can get a better view of their relative positions.

Rotate the wheel towards you and you’ll see the hook and needle move in tandem. It will be obvious how it all works when you see it move in slow motion. Basically hook and needle timing is done by setting the hook at some position like I have it next to the needle and measuring the distance between the hook point and needle eye. There are other measurements like the maximum and minimum height of the needle but I don’t think that’s been changed.

Hope you haven’t broken anything. These machines are incredibly tough with the exception of the nylon gear you just replaced.

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

Success! I have to admit it had me beat for a while after getting that gear in. I just didn't want to go fiddle with it again and the repair manual I have talks about some gauges that I think are factory tools for setting the timing. However, I used the 2.45mm (in range of 2.3-2.6mm) as the "offset from lowest needle point when advancing in the standard direction". It took a bunch of attempts to get the hook aligned correctly but in the end, it's working correctly on all the needle offset positions and with zig zag and all that. Now I know what all the levers do.

I did break the presser bar lever (foot lever?) -- I cracked the end off when replacing the gear earlier. Still possible to operate with the knub but I'll have to fix that. I can probably 3d print something. I think it's this part:

https://www.sewingpartsonline.com/press ... 20-10.aspx

But at least my wife can get back to using it. There were grumblings of buying another machine if I didn't get it fixed soon :).

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Fixit Log

Post by Sclass »

That’s great! I knew you’d get it.

Yes that lever is plastic. But I think the one in your link is the wrong one. Maybe. :?: My recollection is it is more like a flat plate with a little dog leg bend in it. I was tempted to just trace mine out on a piece of aluminum plate or plexiglass sheet and cut it out with a saw and file. Then grind it smooth with a sander. Let me see if I can find it.

https://www.sewingpartsonline.com/press ... 61-10.aspx

I could be wrong but I think it’s actually this one. Several available on eBay. Our machines could be slightly different.

I’ve never broken one but it is considered to be a weak point on these machines. 3d printing is an interesting option. Worth a try. I bet it would print out strong enough lying flat on the build plate. Then you can put the dog leg in with some heat.

Good job and good luck.

SavingWithBabies
Posts: 882
Joined: Mon Aug 31, 2015 2:50 pm
Location: Midwest, USA

Re: Fixit Log

Post by SavingWithBabies »

You're right -- it's that part. I made a replacement one and 3d printed it in PLA. Hopefully, it will not get too hot with the incandescent light bulb next to it. If so, I might just upgrade the lighting (or reprint in ABS). But it'll probably work just fine. I debated using heat for the bend but decided to just design it in and use supports for that part of the arm.

Post Reply