how to change the length of the stitches

[Chamod]

I have a singer 138B8BM post bed machine and I can't change the length of the stitches.There is few numbers displayed in the side of the pulley in the machine,but I can't adjust it.It's stuck.I tried everything I could, but none of that worked.Is there any possible way you know to adjust it.please help...!!

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Edited May 4, 2019 by Chamod

[Constabulary]

I don´t know this particular model but usually there are 1 or 2 buttons in the flat bed. One for the safety clutch and one for the stitch length. If you have two buttons the one to the left is for the stitch length.

I think your machine is based on a Singer 111 / 211. So I would assume the stitch length regulation is similar.

If you already knew this I would guess the stitch length regulator is gummed with old oil.

Edited May 4, 2019 by Constabulary

[Gregg From Keystone Sewing]

Machine is a Seiko, sold for a short time from Singer.  You can see from the image that this machine Seiko embossed on the bed. If you look at the blue square, that's the stitch length regulator.  There must be a push button that yo would press and hold down and then turn the handwheel forward or backward to adjust stitch length.  Press and hold the button down until it falls into a slot lower and turn by hand, not under motor power.

Singer Seiko 138B8BM Parts Book

 

    

Edited May 4, 2019 by Gregg From Keystone Sewing
info@keysew.com

[mikesc]

Having numbers as a guide marked for the stitch length is an advantage when you get it working,.
On the Singer 211 ( like mine ) the mechanism is the same..but..no numbers..just an arrow with two heads , one at each end of the line..plus letter a A about 3 cms further around from the "minus"..and a letter "E" 3 cms further around from the + ..No other marks..!!
They ( Singer ) must have thought that everyone would have the time to "fart about" trying to get the thing into the same position as previously to get the same stitch length..or that the machine operators were phenomenally good at guessing where they had the adjustment set before..

That said..nice machines when you get them worked out. :)

[Gregg From Keystone Sewing]

18 hours ago, mikesc said:

Having numbers as a guide marked for the stitch length is an advantage when you get it working,.
On the Singer 211 ( like mine ) the mechanism is the same..but..no numbers..just an arrow with two heads , one at each end of the line..plus letter a A about 3 cms further around from the "minus"..and a letter "E" 3 cms further around from the + ..No other marks..!!
They ( Singer ) must have thought that everyone would have the time to "fart about" trying to get the thing into the same position as previously to get the same stitch length..or that the machine operators were phenomenally good at guessing where they had the adjustment set before..

That said..nice machines when you get them worked out.

One step forward one step back.  I never knew that about the stitch length until you mentioned it.  The stitch length regulator/incorporated safety clutch still remains a mystery to many people and is very easy to 'knock the machine out of time' when simply adjusting stitch length.  It was not a great idea and didn't for sure improve on the 111W that also had both.  Also the reverse mechanism has very heavy spring presser and you have to stand on it to push it down.  That would get old fast.  Singer also put a silicone lube for thread system incorporated into many of the 211 models and I've yet to see one ever working or really that is not broken.  I do like the push button for the presser feet climb using a worm gear for adjustment, a lot like the modern large plastic dials found on many new walking feet machines.     

Edited May 5, 2019 by Gregg From Keystone Sewing
info@keysew.com

[Handstitched]

G'Day, when I saw those pics, ' Seiko' came to mind.

Yours may be different , but the stitch length adjustment on mine  is in the centre of the bed (see pic ) You can see the button , top right of  the square piece of leather  ( that stops the bobbin cover from  vibrating) .

Also , looking  inside the top hole to the right, I can see the stitch length numbers. For me to adjust the length, I push the button down while turning the flywheel clockwise or anti clockwise . I will hear a ' clunk'  when it clicks in. But its set just right , haven't  touched it  in years .  

This machine is 53 years old now. 

HS

[Chamod]

Thank you everyone who helped me.it works and the stitches length problem is solved.I need another advice from you.what is the purpose of the part in picture 2 and what is the safety clutch? (pic 1).And also what are advantages of the cutting blade (pic 3).When the lever turns left the blade goes down near the needle and foot.When turn that to right it goes up again.Please help me.

Edited May 8, 2019 by Chamod

[Matt S]

The safety clutch is like an over-pressure valve. If you get a needle crash, timing slippage or thread jam so tough that it prevents the "business end" parts (needle, hook, feed dog etc.) from moving but the "back end" parts (balance wheel, top shaft, bottom shaft etc.) keep trying to drive them, something will break before you notice and take your foot off the gas. Hopefully that'll be something cheap like the needle but it could be something expensive like the hook. The safety clutch protects parts from breaking and you from having sharp pieces of metal flying around near your eyes and fingers. In the event that there's excessive torque on the bottom shaft it simply disengages the bottom shaft from the belt sprocket which drives it, reducing or preventing any damage. Fix the fault, hold in the button and turn the balance wheel backwards until it pops back into place. (Then test your timing as it's possible to reset the clutch 180 degrees out of time...)

Your blade looks like a side trimming knife, which is useful in certain production situations. Imagine sewing a soft lining into the upper of a shoe. Clicking the lining to exactly the shape of the upper will require a fiddly and slow glue-up and the edge might be uneven. However if you cut the lining oversize you can glue it quicker and trim after sewing. Now if you put the trimming blade on the sewing machine, next to the needle, you will trim it as you go which will be faster (cheaper).

[mikesc]

Now if you put the trimming blade on the sewing machine, next to the needle, you will trim it as you go which will be faster (cheaper).

If you are not going to be using it, you can take it off ( the blade, not the lever and mechanism ) in case it is sharp enough to cut you, but, you'll probably lose it if you do..Or you can always use a piece of the thin plastic temporary binder channel , that is used to hold two pieces ( or a few pieces of paper ) together along their edges..Put it over the "knife" edge to protect your fingers from it..if you can't find that..some Duct tape wrapped around it neatly two or three times will work..

[Chamod]

Thank you everyone who helped me to solve the problems in my post bed machine......  

God Bless....!!