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Random tension loss


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Theres nothing more annoying than taking the time to remove all the old stitches,after selling your customer a pair of JR through soles, only to have your outsoler randomly lose its tension.

 

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One of the reasons for this, in my opinion is: were the thread comes up through the body of the machine and between the metal blocks with two springs for tension,

 

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The springs are inadequate and the screws haven't enough thread to put enough tension on the thread, causing the thread to periodically slip around the tention wheel.

 

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I wondered if there has been any modification done to this part of the otherwise excellent machine.

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Too much tension and the wheel will not turn, if this is intermittant then it manifests as random tension loss.

Try slackening the tension until the wheel turns without slipping then adjust the tension in the bobbin case to compensate.

 

I found that if you coat the wheel (after cleaning all oil off)with an anti slip spray used in industry to coat driven belts, or even just secure a thin piece of cloth around the centre section this usually allows the thread to grip the wheel and provide a means of getting more tension.

 

I also feel that this part is letting the machine down. The WHB machines of the 60s had a combed finger effect that gripped the thread and was far superior.

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is your thread that is running through the machine (not the bobbin) nearly empty? because I have had instances where as the wind in the thread gets smaller as theres less thread it sometimes snags on the machine as it passes through from under neath

 

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Lee

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few things here. tension problems are to do with the thread as you have suggested.

 

firstly we have found it no good using nylon thread in shuttles of goodyears anymore. the problem is the tension mechanism on them. nylon thread is weaved rather than twisted and if you look at it from one end you will see that instead of it being round in shape it is flat. the shuttle spring relies on compressing the thread and when it wears it lets the thread twist, this can give you the tension - no tension - tension effect. for good locking you must have a nice even tension from the shuttle. our answer is to use a good quality pre waxed linen thread without the tensioner, the wax being enough to give an even tension.

 

secondly it is very important that the locking mechanism is working properly and effectively, this is the most likely cause of your problem. turn the machine over by hand so the thread goes over and around the shuttle to the point it is dropping down again, at this point you should not be able to pull the thread through the machine it should be locked. to adjust the lock you need to loosen the front nut (see picture) and adjust the rear nut until you get the lock right, careful though as only a small adjustment of the back nut makes a big difference to this lock. when happy lock the front nut back again.

 

another thing i do is take the thread around the locking roller twice (it normally only goes under the roller and out again. this negates any wear there may be in the lock finger.

 

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Polyester slips on shiny metal, hence the need for a coat on the surface to remove the friction aspect. (just my theory but i did try it years ago with a 1/4" strip of linen wraped round and it did solve the problem until I changed to the WHB type)

 

I presume Uk knows about the lock mechanism Peter, if not, as you say undo the front anticlockwise just 1 full turn at a time and tighten the back anticlockwise by the same amount.

too much lock and you will have a broken casting.

You could aslo change the bobbin case for one that has a decent tension device if they still do them, modern ones in my view are crap as they wont tolerate poyester or fine thread.(my views only).

 

As it is probably a newish machine the next bit of advice may not apply but check just in case.

Cheack that all the rollers that the thread goes around are freely rotational and not dry orcoaten in solid wax.

Check that a groove has not worn in the rollers that will have the effect of the roller lying in the same position with the groove at the bottom. This was a common fault when rollers were not lubricated and run with dry thread.

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Thanks for the replys guys, I know how to alter the lock, and all the moving parts, roller wheels etc are in excellent working order. I do believe that the random tension fault is partly to do with the machanism as the thread leaves the body of the machine, as there is almost nothing to stop the thread from slipping around the tension wheel, But I will try the linen thread in the shuttle tomorrow, as you say Peter, with the nylon thread there is no tension whosoever. Thanks again guys. :wink:

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i never turn the nut a full turn, i start a bit at a time usually a quarter turn till it gets where i need it. this is for the reason you mention hugh, broken bits when you then try to run it.

 

shuttle changing to a better tension system is not an option now either. the only new ones available are sutton landis american ones that are the wrong side of £200.00. even then the tension system is not that clever with braided thread that when it twists is wider than when it is flat. sure the shuttle thread change to linen will be the sure.

 

the other thing i remembered is the nylon thread is coated and has a past best point. the coating can become sticky if it is an older stock and this can cause havoc with tension but if this was the case i would expect the problem to be more consistent

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Do me a favour and try Peters tip of winding the thread around the tension wheel twice, it does stop slip and I'm interested to see if it will work on your machine.

 

It is wrapped round twice already Hugh, A theory I have is.....These machines were made to work with a linen thread, Top & bottom.

when the awl makes its hole for the needle to pick up the thread, the gauge of the never strand is almost nothing, and the two thread combined lie loosely in the hole that the awl has made, leaving it very difficult to get the tension correct.

with the linen thread the gauge is much greater and needs pulling down into the hole. (I don't know if I have explained myself very well here)

 

The machine is in excellent condition, and I am reluctant to start using Linen thread because then you need wax. and as we all know usage of outsoling isn't as gtreat as it used to be, and the wax goes hard etc etc etc.

 

so this morning I will try linen thread in the bobbin only. thanks again guys. :wink:

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the intention is to wrap the thread around the locking roller didnt mean the tension roller. this gives the lock finger a better chance of gripping the thinner nylon thread. we use a pre waxed linen in the shuttle, not dry linen which will not give much grip

 

Sorry Peter, I misunderstood, another tip I can try :P

Its bloody annoying when you make a good job only for the stitcher to louse it up :evil: Took them home last night and unpicked the stitches so I'll be pi55ed if it does it again :twisted:

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It's great when all involved know exactly what your talking about :D

 

Imagine a member of the public reading this.... They'd think we were a right load of sad gits :lol:

 

Lee's right here, an intermitant problem is worse. Its no good just altering the tension, something needs to be changed.

got loads to go on, I'll let you know how I get on. Ta !!

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That picture of a tension wheel looks like it has been exported from a Mascotte/Fimac blake!!!

 

I aint used to these square box goodyears but, on the Mascotte that tension wheel I believe is not a tension wheel but a thread straightening aid, is it now being used as a tensioner on the goodyear? (may be wrong but was given this advice by an eminent engineer from Italy many years ago.

 

Goodyears dont look like stitchers any more, more like a blooming cabinet. Customers used to love watching shoes being stitched at full speed in the window, bet these new things dont go as fast as the one I had with a 3ph motor on :lol: We used to call it the blue rocket (this was before man landed on the moon by the way :wink: )

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think it is similar more to the dn76 tension device. as for the older machines unfortunately the old elf & safety jumped in there. new machines are electronically controlled for speed and can be pre set to be very slow or very fast (as fast as the old stitchers) i normally set them a bit on the slow side although if you go too slow you break far more needles. the cabinet design is to fit in with the design of the insole stitchers.

 

i must admit, there is nothing like the sound of the old goodyears working away with their flat and round leather belts wizzing round, fascinating. and imagine how messed up the designers brain must have been getting all those cams and rollers etc to work together to get the end product. those victorians knew a thing or two, no computers either.

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