Singer 29K70 vs 29K71 vs 29K72

[Evo160K]

What are the primary differences among these three machines?  Is the 70 the oldest subclass?

Thank you

[MADMAX22]

http://ismacs.net/singer_sewing_machine_company/model-list/classes-1-99.html

That should get ya started. The 72 is the big bobbin from the looks of it. I dont have much info on them but there are several threads on the forum with info. 

[Constabulary]

29K are sometimes a bit confusing because the difference between 2 subclasses sometimes is just the presence of a wax pot (or not) or a side wheel (or not) or if the machine has a small or large bobbin... The 29K parts list sometimes tell the differences. They write "Same machine as 29K.... but with the following differences..." - or the like.

29K70 short arm, small bobbin, no side wheel - 29K71 short arm, small bobbin, with side wheel, 29K72 long arm, large bobbin, with side wheel,

With side wheel they mean the detachable hand wheel on the front side.The machines with just an end wheel sometimes are lacking the wooden crank knob. Not sure on the 70´s subclass but the early 29K´s with just end wheel often do not have the crank knob.

[shoepatcher]

C,

The side wheel was on some of the subclass up to the 29k51-56.  After that, the front wheel mount was an extra charge, not standard.  Machines might have the front bub, but not the shaft and gear.  The 29K70  came out after the 29k58,60 and 62 series.  It came out only on its own.  Don't know why.  It was replaced by the 29K71 which was part of the 29K72 and 29K73 which was a series . very few parts changed in that series compared to the 58,60,62 series.

glenn

[Evo160K]

Thank you Gentlemen.  Sincerely appreciate your information.  I was intrigued by the fact the subclass stands alone, (as Glenn mentioned), with so many similar machines immediately before and after.  Didn't seem to make sense to me.

What advantages did it have?.  Was it a popular subclass?

 

[Constabulary]

Not sure when they have introduced the excenter for adjusting the timing but I think that came in the 30´s subclasses but not sure.

The parts of the sewing head "almost" remained the same since the introduction of the helical presser spring (51 sub class) but there are some minor differences since there are very few subclasses that have a longer stitch length (like 29K52 / 29K54) than the "standard" 29K´s but they are rare as the hens teeth I´d say. I never have seen one. And I never read somewhere how much longer the stitch length is.

The advantage of the later sub classes form 51 onward (51-56 if I´m right) is the helical presser spring instead of the blade spring on the back side plus the foot lift hight during the sewing operation can be adjusted by a "slide piece" secured with a wing nut on the backside of the head and you can adjust the presser foot hight the way that the presser foot does not touch the plate - maybe that's useful for thicker works - I´m not sure but that's at least one of the inventions in this subclass range. They also had a "drop out" gear box, whereas the earlier had a fix gear box in the lower arm. The gears in this range are critical as they have very fine teeth and spares are no longer available - or you have luck and find some old stock.

From the 58 subclass onward (58-62) the machines have a "quick release" for the hand wheel. You can pull and turn a plunger then only the hand wheel spins when you wind the bobbin. The predecessors had a fixed hand wheel and the the whole machine mechanics runs when you wind the bobbins. You also have one big screw that holds the hand wheel on the shafts. Predecessors had two set screws. But you have an adapter the hand wheel sits on and when you want to switch the hand wheel from front to side you also have to remove the adapter which also is secured with 2 set screws.

From the 58 onward the machines no longer had the plain screw and nut as thread adjuster on the arm lever. Instead they had an adjuster unit with thumbscrew dial. They also have a fully replaceable lower arm horn which includes the gear box. And as far as I remember there is a screw post with thumb screw on the upper arm for regulating the spring for the thread lever. That formally was just a plain screw.

Not sure what the update on the 70´s subclass was but I remember there no longer it s screw that holds the needle plate instead there is a "mushroom pin" secured with a set screw from the front.

Basically - the higher the subclass number the more technically advanced the machine is and the better is the chance for finding spare parts.

So if I was looking for a used 29K patcher machine that I want to use for a long time and parts have be available I´d look for a machine from the 58 subclass onward since most of the parts from the "up to date" 71 / 72 / 73 subclass fit these machine. Or in best case find one for the 71 onward.

I looked for a long time until I found a 29K71 short arm but it was in quite bad shape so I have restored it and I´m more than pleased with it. I only wish it had a large hook. I know there was a 29K short arm model with large hook. Glenn mentioned it a while ago but I have never seen one of them.

I hope I have not mixed up something... Too many details on these machines have changed over the years.

I´m sure Glenn / Shoepatcher knows more details.

 

Edited October 24, 2016 by Constabulary

[shoepatcher]

C,

To my knowledge, the only short arm that Singer ever made with the large hook was the 29U171 which was made in Japan in the late 70's.  It looked a little different than any other Singer shoepatcher.  I have an original brochure on the machine.

glenn