Advice on a Recently Purchased Claes 8346-30 Patcher Sewing Machine

[ya2daup]

Good afternoon all,

First off, thank you all for the years of information on this site. I recently created a login and this is my first post but I've been quietly soaking up the wealth of advice for over a year.

I just picked up a Claes 8436-30 for a great price and would appreciate some help getting it tuned up and ready to go. Everything seems to rotate smoothly and corrosion is at a minimum. I haven't tried sewing with it yet but am hopeful that it'll take off without much effort.

I found a couple other posts about these machines and found them helpful, but would appreciate a bit more info. Also, my documentation is in German and would appreciate it if anyone could help me track down the user and maintenance manuals. 

It looks like it was either set up with a motor at one time or darn close to it. Can anyone recommend what size servo motor I should put on it. And how imortant is a speed reducer and needle positioning sensor?

@shoepatcher, @Constabulary. Sorry for the tag but you two seemed to have a lot of great input on the other posts I saw.

I'm attaching photos of the machine and the hardware it came with. Thanks in advance for your help

 

Edited July 11 by Northmount
Title corrected

[friquant]

 

On 7/9/2025 at 4:55 PM, ya2daup said:

Can anyone recommend what size servo motor I should put on it. And how important is a speed reducer and needle positioning sensor?

What materials do you anticipate sewing, and how thick?

With your other sewing machines, which would you rather have: A. Slow gentle startup, or B. The convenience of a needle positioner?

It seems that there are two camps of servo motors. With an analog servo motor you supposedly get slow gentle startup, but not necessarily support for needle positioners.  With a digital servo motor you get decent support for needle positioners but you get a jerky startup. Some have reported that their needle positioners did not work when they added a speed reducer. 

If your servo motor has a standard 15mm cylindrical shaft with a woodruff key in it, you can buy an aftermarket 45mm pulley (75mm is standard) for about $10 to get some speed reduction. 

 

 

[ya2daup]

2 hours ago, friquant said:

 

What materials do you anticipate sewing, and how thick?

With your other sewing machines, which would you rather have: A. Slow gentle startup, or B. The convenience of a needle positioner?

It seems that there are two camps of servo motors. With an analog servo motor you supposedly get slow gentle startup, but not necessarily support for needle positioners.  With a digital servo motor you get decent support for needle positioners but you get a jerky startup. Some have reported that their needle positioners did not work when they added a speed reducer. 

If your servo motor has a standard 15mm cylindrical shaft with a woodruff key in it, you can buy an aftermarket 45mm pulley (75mm is standard) for about $10 to get some speed reduction. 

 

 

Thank you for your reply.

Materials/intended use: I'm using it for general repairs and small batch fabrication. Anything from lighter weight materials up to max thickness leather and boot soles. So I would prioritize control and accuracy over speed.

I also have a Consew 206RB-5, I swapped out the clutch motor for a servo with the smaller pulley last fall (I did not get a needle positioning sensor). I went back and looked at the product listing and it doesn't mention whether or not it's digital or analog, only that it's a 750W Brushless Servo Motor. It does seem a bit jerky at startup and even on the lowest setting there are times I wished it moved a bit slower.

*EDIT* On second thought, is analog vs digital as simple as a dial controller vs a digital display? If so, the one I have is digital.

Edited July 11 by ya2daup

[friquant]

1 hour ago, ya2daup said:

is analog vs digital as simple as a dial controller vs a digital display

In practice, yes. What I really mean by this distinction is whether they have a minimum speed or not, and the ones with a digital display seem to have a minimum speed. They're either not moving at all, or they are moving at least at their minimum speed.

And by analog, I mean you can ease into the gas pedal and start out at a crawl.

What is the minimum speed of the servo motor on your consew? It's easy to find a "digital" servo motor with a minimum speed as low as 200 rpm, which with a 45mm motor pulley gave me 111 stitches per minute with an 80mm hand wheel pulley. Your setup may be slower if your handwheel is larger than 80mm. If you want slower than that, they you either need a speed reducer, or an "analog" servo, or both.

I don't work with thick leather, so I will let others chime in regarding whether you will need a speed reducer in order to stitch the thick materials you are targeting.

 

Edited July 11 by friquant

[ya2daup]

Well it appears that I have bigger issues. I got it threaded up and the top thread doesn't want to pickup the bobbin thread. I put in an empty shuttle and cycled it with the bobbin holder door open and it appears that the machine is WAY out of time. The fact that the back cover was off when I purchased it seems a bit dubious. I'm mechanically inclined but with such little information available about these machines I'm not sure where to start. I can post videos if anyone is willing to help troubleshoot. I'd happily pay for some online tutelage.

[friquant]

Yes, do post videos. 
Have you done timing on your RB5?

[ya2daup]

24 minutes ago, friquant said:

Yes, do post videos. 
Have you done timing on your RB5?

Thankfully I haven't had to adjust the Consew, it runs like a dream. The pickup timing on the Claes appears to be way off and there's also some odd play in the main shaft running from the pully over to the head. I'll post a couple videos tomorrow. Thanks again.

[Northmount]

8 hours ago, ya2daup said:

Thankfully I haven't had to adjust the Consew, it runs like a dream. The pickup timing on the Claes appears to be way off and there's also some odd play in the main shaft running from the pully over to the head. I'll post a couple videos tomorrow. Thanks again.

Post the video on YouTube and link to it here. Need more than 5 seconds that fits file size restrictions here. 

[Cumberland Highpower]

Sewing machines are simple machines and anything can be fixed.  It's probably just a timing or adjustment problem rather than a parts one.  

I don't think that machine can handle much sole work, if any?  I think most buy them for things like sewing patches on jackets and shoe upper repair work in 4/5oz or less shoe leather.

Positioner on a shoe patcher might be not worth the effort, you'd be better off just to set it up to run slow.   Positioners are more for speedy production machines and a patcher isn't really one. Slow sewing design w/small bobbin.

[kgg]

13 hours ago, ya2daup said:

Anything from lighter weight materials up to max thickness leather and boot soles.

I am wondering what you mean by " up to max thickness "?????

In my opinion Patchers are not meant for boot soles. The max sewing thickness of that machine is less then a 1/2" at 12mm (15/32").

On 7/9/2025 at 8:55 PM, ya2daup said:

Claes 8436-30

I assume you meant Claes 8346-30.

Here is a good manual that you can download ( https://www.manualslib.com/manual/3027579/Claes-8346.html?page=3#manual)

kgg

[Cumberland Highpower]

15 hours ago, ya2daup said:

Well it appears that I have bigger issues. I got it threaded up and the top thread doesn't want to pickup the bobbin thread. I put in an empty shuttle and cycled it with the bobbin holder door open and it appears that the machine is WAY out of time. The fact that the back cover was off when I purchased it seems a bit dubious. I'm mechanically inclined but with such little information available about these machines I'm not sure where to start. I can post videos if anyone is willing to help troubleshoot. I'd happily pay for some online tutelage.

Are you certain you're using the right needles?  A needle too short or too long can give you the illusion of being out of time. Might sound like a silly suggestion but sometimes could be the case?   Just look over the mechanisms, you should be able to "see" what the problem is with a little careful analysis. 

Edited July 11 by Cumberland Highpower

[ya2daup]

19 hours ago, friquant said:

What is the minimum speed of the servo motor on your consew? It's easy to find a "digital" servo motor with a minimum speed as low as 200 rpm, which with a 45mm motor pulley gave me 111 stitches per minute with an 80mm hand wheel pulley. Your setup may be slower if your handwheel is larger than 80mm. If you want slower than that, they you either need a speed reducer, or an "analog" servo, or both.

My Consew's servo has a min of 400 rpm and I have the smaller pulley installed. If anything a needle positioner would be nice on this machine. As for the Claes I think I'll get a speed reducer to really slow it down.

 

6 hours ago, kgg said:

I am wondering what you mean by " up to max thickness "?????

In my opinion Patchers are not meant for boot soles. The max sewing thickness of that machine is less then a 1/2" at 12mm (15/32").

I assume you meant Claes 8346-30.

Here is a good manual that you can download ( https://www.manualslib.com/manual/3027579/Claes-8346.html?page=3#manual)

kgg

Yup, thanks for the correction on model number. For some reason I've been transposing the 3 and the 4 ever since I first read about this model. I can't find a way to change the title or I would...

I'm sure you're right about boot soles. I don't really have any goals with the machine other than to be able to get into tight places for boot and backpack repairs. If it did soles that would be a bonus but not a deal breaker. 

Thanks for the link, that manual seems to be posted on a few websites. I also have a document with drawings of individual components but that one is in German. I've seen posts regarding a mechanics manual but I can't seem to find one posted online.

 

8 hours ago, Cumberland Highpower said:

Sewing machines are simple machines and anything can be fixed.  It's probably just a timing or adjustment problem rather than a parts one.  

I don't think that machine can handle much sole work, if any?  I think most buy them for things like sewing patches on jackets and shoe upper repair work in 4/5oz or less shoe leather.

Positioner on a shoe patcher might be not worth the effort, you'd be better off just to set it up to run slow.   Positioners are more for speedy production machines and a patcher isn't really one. Slow sewing design w/small bobbin.

Hopefully you're right on the adjustment. We'll see what everyone thinks after looking at the video.

No worries on the sole work, just brainstorming what things I may attempt to repair.

Yup, I think slowing the machine down to a crawl would beneficial than a positioner.

 

2 hours ago, Cumberland Highpower said:

Are you certain you're using the right needles?  A needle too short or too long can give you the illusion of being out of time. Might sound like a silly suggestion but sometimes could be the case?   Just look over the mechanisms, you should be able to "see" what the problem is with a little careful analysis. 

It came with a couple dozen 88 needles, I didn't see any 81s in the batch.

Here's the uploaded video. Along with the needle timing I'm also concerned about the horizontal play in the main shaft. You can hear it "clunk" into place every rotation.

Here's the Youtube link, hopefully it's good enough: 

 

 

Edited July 11 by ya2daup

[Northmount]

1 hour ago, ya2daup said:

Yup, thanks for the correction on model number. For some reason I've been transposing the 3 and the 4 ever since I first read about this model. I can't find a way to change the title or I would...

I'll fix the title in a few minutes.

[friquant]

I can see that the timing is off, as it moves too far clockwise / not far enough counterclockise to drag the thread around the bobbin. (Even if it did manage to pick up the thread in the first place) 

 I have not been able to find a service manual for this machine. As @Cumberland Highpower said: "Just look over the mechanisms, you should be able to "see" what the problem is with a little careful analysis."

I would start by removing/opening covers. See if you can trace the movement of the hook all the way back to the main shaft. That is, figure out which shafts, rods, gears, cams, and/or arms are involved in making the hook turn. At least of of those members will be adjustable in a way that allows you to change the hook timing. Feel free to post additional videos as you make progress.

Once you figure out what to adjust to effect a timing change, try setting the hook so that in its clockwise swing the point of the hook only goes about 5mm past the needle before the hook turns around to go counterclockwise. I expect that will put you in the ballpark where it will actually sew.

Edited July 13 by friquant

[Constabulary]

Looks like a model from the 1980 which is slightly different to the latest model. IIRC the blade spring on the rear is a different one on the latest model but thats the only major difference I recall. Right now I have a very similar machine here and can take some pictures if you need assistance.

Some time (years) ago I translated a 8346 mechanics manual from German to English for one of our members (seems I had a lot of spare time back then 😊) but I have to look for it in my records. I´ll send you a PM if I find it.

BTW some of the parts I see in the pictures obviously do not belong to this machine. FI the Singer class 15 bobbins and the bobbin cases.

Edited July 13 by Constabulary

[ya2daup]

On 7/12/2025 at 6:50 PM, friquant said:

I can see that the timing is off, as it moves too far clockwise / not far enough counterclockise to drag the thread around the bobbin. (Even if it did manage to pick up the thread in the first place) 

 I have not been able to find a service manual for this machine. As @Cumberland Highpower said: "Just look over the mechanisms, you should be able to "see" what the problem is with a little careful analysis."

I would start by removing/opening covers. See if you can trace the movement of the hook all the way back to the main shaft. That is, figure out which shafts, rods, gears, cams, and/or arms are involved in making the hook turn. At least of of those members will be adjustable in a way that allows you to change the hook timing. Feel free to post additional videos as you make progress.

Once you figure out what to adjust to effect a timing change, try setting the hook so that in its clockwise swing the point of the hook only goes about 5mm past the needle before the hook turns around to go counterclockwise. I expect that will put you in the ballpark where it will actually sew.

Success! I was able to remove the cover underneath the shuttle assembly (not sure if that's the correct terminology) and move it around until it started picking up the bobbin thread. I did some test sewing and it appears to be working well! Any thoughts on the horizontal play in the main shaft that is connected to the motor pulley? At the top of the cycle it moves about 1/4 inch and then "clunks" back into place as it continues the cycle. I can't think of any reason why it would do this and want to make sure using it like this isn't going to cause undue wear.

Once I'm confident that it's operating correctly I can start work on the motor, trundle and speed reducer.

On 7/13/2025 at 1:58 AM, Constabulary said:

Looks like a model from the 1980 which is slightly different to the latest model. IIRC the blade spring on the rear is a different one on the latest model but thats the only major difference I recall. Right now I have a very similar machine here and can take some pictures if you need assistance.

Some time (years) ago I translated a 8346 mechanics manual from German to English for one of our members (seems I had a lot of spare time back then 😊) but I have to look for it in my records. I´ll send you a PM if I find it.

BTW some of the parts I see in the pictures obviously do not belong to this machine. FI the Singer class 15 bobbins and the bobbin cases.

I do believe you're correct on the age. The serial number ends in 86, which I believe is the manufacturing year.

I did see that old post about you having an english translation for the mechanics manual. I didn't realize you did the translation yourself. I'm sure they were very appreciative! If you can locate it I would be very grateful if you would send me a copy.

The old owner removed the motor and trundle connections so any pictures of that setup would also be greatly appreciated.

 

[friquant]

13 hours ago, ya2daup said:

Any thoughts on the horizontal play in the main shaft that is connected to the motor pulley?

Are you saying the main shaft moves horizontally (and takes the handwheel with it)? Send a video maybe.

You might try preventing the horizontal movement to see if the machine can still turn without binding up. If it binds up without the horizontal movement, then maybe the horizontal movement is by design.

Also check to see if there are any screws loose near the main shaft whose job it might be to keep the shaft in place. On domestic machines I've seen C-clips used to prevent horizontal movement of the hook shaft. If a C-clip were missing, there would be a groove cut in the shaft but nothing in it.

[ya2daup]

1 hour ago, friquant said:

Are you saying the main shaft moves horizontally (and takes the handwheel with it)? Send a video maybe.

You might try preventing the horizontal movement to see if the machine can still turn without binding up. If it binds up without the horizontal movement, then maybe the horizontal movement is by design.

Also check to see if there are any screws loose near the main shaft whose job it might be to keep the shaft in place. On domestic machines I've seen C-clips used to prevent horizontal movement of the hook shaft. If a C-clip were missing, there would be a groove cut in the shaft but nothing in it.

If you look at the second half of my video above it shows the movement I'm speaking of, but I'm happy to take another video. Oddly enough the hand wheel doesn't move, the motor pully and the whole shaft, all the way out to the sewing head, moves. I'll find something to act as a shim and see what impeding the movement does. Let me know if you would like a separate video. Much appreciated.

[ya2daup]

On 7/13/2025 at 1:58 AM, Constabulary said:

BTW some of the parts I see in the pictures obviously do not belong to this machine. FI the Singer class 15 bobbins and the bobbin cases.

Thanks for the spare bobbin identification, I knew it didn't go with the machine and they're smaller than what's on my Consew. Unless anyone reading this thread want's them for cheap I'll list them on ebay. I also think the bobbin winder came from a different machine, I wouldn't think there would be much of a secondary market for that.

[friquant]

4 hours ago, ya2daup said:

Oddly enough the hand wheel doesn't move, the motor pully and the whole shaft, all the way out to the sewing head, moves.

Forgot that you have two hand wheels! Or one giant handwheel and two motor pulleys (one on the motor, one one the patcher). This is going to mess up my terminology notes for sure 🤷‍♂️

From your video, I'm not sure if that lateral motion is a problem, a feature, or neither. Is there anything along the main shaft that looks like it's intended to impede this lateral motion?

 

[Constabulary]

Here are some pictures of my 8346-30.

BTW when you look at the data plate the number below "BAUJAHR" is the year when it was made.

[Constabulary]

some more

Hope the pics help setting up yours. Mine still has thee original clutch motor but your seem to have a modern servo motor alreday. If you need more detailed pictures let me know.

[shoepatcher]

You have lots of parts.  Need a servo motor for it.  Does the engraved line on the front of the base say 8345-6 or 8346-6?   It has an early Claes cast iron stand almost like

the Pfaff Metro Spezial that was a Claes in everything but name.  Claes sold machines to Pfaff that Pfaff out their name on it.   What questions do you have on the machine?

glenn

[ya2daup]

On 7/15/2025 at 1:33 PM, friquant said:

Forgot that you have two hand wheels! Or one giant handwheel and two motor pulleys (one on the motor, one one the patcher). This is going to mess up my terminology notes for sure 🤷‍♂️

From your video, I'm not sure if that lateral motion is a problem, a feature, or neither. Is there anything along the main shaft that looks like it's intended to impede this lateral motion?

 

Ha! Sorry about that, I think you got the picture but I'm referring to the motor pulley on the patcher. I've spent some time looking it over, along with the engineering diagram I have (in German) It appears that everything on that shaft is pinned and has a sew screw so I don't see any opportunity for adjustment. I did pop the pin on the aformentioned pulley and tapped it in further which does take up the slop but without the pin that's not a long term solution. At this point I don't believe there is any solution within the machines available adjustments but the "clunking" is going to get annoying. So I think I'm going to pull off the pulley and insert a couple nylon washers. Not so much that it's tight and binding but enough so that it has minimal travel

On 7/16/2025 at 12:48 AM, Constabulary said:

Here are some pictures of my 8346-30.

BTW when you look at the data plate the number below "BAUJAHR" is the year when it was made.

 

Thank you for all the pictures! It really helped identify some of that parts and what I should be considering when finishing the setup. I went ahead and ordered a servo motor and speed reducer. I'll have to make a couple custom mounts but for the most part I'm happy with the progress and plan.

I looked at the plate again, it was made in '81

On 7/16/2025 at 9:16 AM, shoepatcher said:

You have lots of parts.  Need a servo motor for it.  Does the engraved line on the front of the base say 8345-6 or 8346-6?   It has an early Claes cast iron stand almost like

the Pfaff Metro Spezial that was a Claes in everything but name.  Claes sold machines to Pfaff that Pfaff out their name on it.   What questions do you have on the machine?

glenn

I'm not sure what engraving on the base you're referring to. The serial number plate on the machine says 8346/30. Now that it's sewing well and I have some more background info I went ahead and ordered a servo and a speed reducer. Other than my concern about the main shaft's horizontal movement (and the associated slop in the hand crank's spider gear) I think we're on the right track!

[friquant]

57 minutes ago, ya2daup said:

So I think I'm going to pull off the pulley and insert a couple nylon washers. Not so much that it's tight and binding but enough so that it has minimal travel

That sounds good to me