Adler 67 Timing Belt Placement

[HardenGoods]

Anyone know if the Adler 67 (subclass GK373) has factory notches on or near the main shafts and gears for point of reference when replacing the timing belt?

I’ve seen several machines with markings on the underside so as to know when the shaft and gear are in the correct position, I just don’t see them on this particular Adler head. I’ve read the service manual but don’t see any mention of the timing belt (other than part identification).

Any help is super appreciated.

 

 

[Uwe]

Designs like the SInger 111W drive the feed dog motion from the lower shaft, so in that case the upper and lower shaft need to be synchronized. That's where you'll find those shaft synchronization marks. 

The Adler 67 design drives feed dog motions (lift and feed) directly from the upper shaft, so no synchronization between upper and lower shaft is required. The lower shaft only drives the hook (and optional thread cutting cam). The hook itself can be freely adjusted on its own.

The cone/bevel gears on the other hand usually do have factory marks on them that indicate which teeth should mesh. Watch out for them if separate the cone/bevel gears. The gears may still work but may be noisy and wear more quickly if they're not properly meshed.

Edited August 4, 2018 by Uwe

[HardenGoods]

On 2018-08-04 at 4:14 PM, Uwe said:

Designs like the SInger 111W drive the feed dog motion from the lower shaft, so in that case the upper and lower shaft need to be synchronized. That's where you'll find those shaft synchronization marks. 

The Adler 67 design drives feed dog motions (lift and feed) directly from the upper shaft, so no synchronization between upper and lower shaft is required. The lower shaft only drives the hook (and optional thread cutting cam). The hook itself can be freely adjusted on its own.

The cone/bevel gears on the other hand usually do have factory marks on them that indicate which teeth should mesh. Watch out for them if separate the cone/bevel gears. The gears may still work but may be noisy and wear more quickly if they're not properly meshed.

Thanks for this info!

[CowboyBob]

Yes,there's no marks to line up BUT there is a feed lift cam ON the bottom shaft  & if it's wrong you'll have to readjust it & the hook timing too.So the easiest thing to do is when you go to put the belt on is rotate the center lower shaft so the feed dog is just coming up through the needle plate,then slide the belt on.So if when you get done turn it around & check your timing if it's off you need to slide the belt off & turn which ever way it needs to go to sew w/o re-adjusting the timing.Because if that way you won't have to adj the cam or the timing.

[HardenGoods]

1 hour ago, CowboyBob said:

Yes,there's no marks to line up BUT there is a feed lift cam ON the bottom shaft  & if it's wrong you'll have to readjust it & the hook timing too.So the easiest thing to do is when you go to put the belt on is rotate the center lower shaft so the feed dog is just coming up through the needle plate,then slide the belt on.So if when you get done turn it around & check your timing if it's off you need to slide the belt off & turn which ever way it needs to go to sew w/o re-adjusting the timing.Because if that way you won't have to adj the cam or the timing.

That makes a lot of sense Bob. I had wondered about that too because I’ve adjusted the feed dog on this particular machine several times from underneath. The main reason I asked the question in the first place was because I’m trying to see if it is possible to advance the takeup lever to hook timing because my thread is very tight when passing around the hook and seems like it is due to the takeup lever being early (as I’m pretty sure the take up lever shouldn’t start it’s ascent until the thread is at the 3:00 position around the bobbin case).

 

Edited August 13, 2018 by HardenGoods

[Uwe]

On 8/4/2018 at 4:14 PM, Uwe said:

The Adler 67 design drives feed dog motions (lift and feed) directly from the upper shaft,

So that statement turned out to be not entirely true, only partially. I'll have to have a word with my fact checker . . .

It sounds like your hook timing is retarded, (hook arrives at the needle too late). I'd try advancing the hook timing a little and adjusting needle bar height to suit. Can you post a picture of the top of the hook when the needle is precisely at bottom dead center?

To my knowledge, there's no way to adjust the relative movement between needle bar and take-up lever on this machine. But I have a history of being wrong on occasion.

 

[HardenGoods]

On 2018-08-13 at 6:33 PM, Uwe said:

So that statement turned out to be not entirely true, only partially. I'll have to have a word with my fact checker . . .

It sounds like your hook timing is retarded, (hook arrives at the needle too late). I'd try advancing the hook timing a little and adjusting needle bar height to suit. Can you post a picture of the top of the hook when the needle is precisely at bottom dead center?

To my knowledge, there's no way to adjust the relative movement between needle bar and take-up lever on this machine. But I have a history of being wrong on occasion.

 

The movement of the hook has helped but the thread continues to get caught up on the edge of the throat plate as the knot is forming which then causes jerking in the check spring. Photo below. 

I can also take another snap of the hook with needle at bottom dead centre if that helps!

[Uwe]

It looks like there's not enough of a gap between the hook and the throat plate. It's possible tolerances of aftermarket parts added up the wrong way. The hook is not original but I can't quite tell if the throat plate is.

If the throat plate was inexpensive, it may be worth grinding a little (with a Dremel) and polishing a lot to enlarge the gap where the thread snags. It's important that this area is very smooth because the thread needs to slide past it without catching a burr or any other imperfection. You want very smooth, rounded edges there, not sharp machined corners. The OEM and worthy aftermarket parts are usually carefully polished in key areas.

I marked up a picture of a throat plate to show the area I think may need to be inspected and potentially modified/polished on your throat plate.

[HardenGoods]

1 hour ago, Uwe said:

It looks like there's not enough of a gap between the hook and the throat plate. It's possible tolerances of aftermarket parts added up the wrong way. The hook is not original but I can't quite tell if the throat plate is.

Thanks for the photo! The throat plate in the photo Is aftermarket (KH) but I do have the original Adler and the problem persists. Going to put new hook in tomorrow to see if the distance between plate and hook is any different. I think you are right - will try the grind and super polish on the aftermarket plate to see if any change in result.

[Uwe]

Chances are it's not actually the throat plate's fault, but it's the easier and cheaper part to modify.

The real cause may be the top of the hook not being as low as it should or the hook being too close to the throat plate due to a worn tip. The too-high hook could be due to slightly too-thick needle guard washer or the hook just being a tiny bit taller than the original. Half a millimeter or so can make all the difference. Make sure there's no thread bits stuck under the hook which may raise the hook's position a tiny bit when reinstalling. I made a video about removing and re-installing the Adler 67 series hook some time ago. 

The too-close hook may be due to a tip that was significantly worn. The hook may have been moved closer to the needle (and thus throat plate). On a new hook the pristine tip will stick out a little more and require you to move the hook away from the needle. That alone may open up the passageway between the hook and the throat plate enough to resolve the snagging thread issue.  

A worn and too-short hook tip may also require an advanced hook rotation to make it work, which in turn may bring a taller part of the hook close to the throat plate sooner than it should. It's all connected and sometimes it requires a series of fixes and adjustments.

I've worked on machines that had multiple parts very worn and multiple adjustments made to compensate for that wear. When I install a new part that is to spec, things are suddenly too tight and all manner of problems manifest, setting off a cascade of adjustments and new parts.

Edited August 30, 2018 by Uwe

[HardenGoods]

2 hours ago, Uwe said:

Chances are it's not actually the throat plate's fault.

I've worked on machines that had multiple parts very worn and multiple adjustments made to compensate for that wear. When I install a new part that is to spec, things are suddenly too tight and all manner of problems manifest, setting off a cascade of adjustments and new parts.

Totally. And the fact that I have an extra throat plate to experiment with is a plus too. I’ve watched you Adler 67 video at least 50 times haha. That’s what started me down this path. 

I remember installing a brand new hook and, as you said, everything was slightly off. Had to move the hook assembly over slightly to make room (which means someone had compensated for the wear before) with the two fasteners that were stuck in your video. 

Going to pull out the mechanics manual and double check the proper distance between hook tip and needle.