Sewing Machines using lighter thread on bottom and heavy on top???

[Rocky Jones]

I saw a thread on this once and now can't find it anywhere, I am using a singer 29-4 and want to use size 69 on bottom and a heavier thread on top.
Any sugestions?
Anyone know where to get the prewound bobbins size type ect???
Thanks
DRJ

[Triggersmith]

I used to have a commercial walking foot sewing maching that I did everything to upholstry to sewing custom stunt kites and just about every material you could imagine.  I never had any luck using dis-similar size threads and getting a nice even stitch.  There is a difference in the way the thread feeds through the needle and the bobben.  I'm not saying it can't be done because someone has probably done it.  I think my question is,  why would you want to do do it at all?
Triggersmith

[Rocky Jones]

It is just something that I want to experiment with.
I am mainly wanting to know the correct size of prewound bobbins for this machine.
In case I run across some on ebay or the local flea market.
thanks
Darrin

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[Slowhand Bob]

I'm not familiar with your machine but use 207 for bobbins and 277 for top stitch on my two Tippmanns while the 277 serves as bobbin thread for size 346 top thread on my Toro 4000.  Both companies recommend one size smaller thread on the bobbin than the top but I'm not familiar with anyone selling preloaded bobbins for the big leather machines.  I'm not even sure that the big heavy leather machines even use a standardised bobbin as my two brands use different sizes.

[Triggersmith]

That's interesting Bob.  Why do they want you to use two different thread weights on the leather machines?  Do you have a tension adjustment on the bobbin? Where can I get some information on this?  I'm used to a high speed commercial upholstry machine.
Triggersmith

[Klondike]

Not sure if you can get pre-wound bobbins for heavy machines, really would not be worth while. I  bought 100 bobbins off Ebay for my machines, very reasonable. I have an industrial bobbin winder on both machines, but neither have a free wheel to load bobbins. You are supposed to wind bobbins as you sew. Sooo, I use my trusty cordless drill with a screw driver bit that fits the bobbin winder and load as many bobbins as I want ahead of time, the automatic disengage even works that way too. You can buy a bobbin winder off Ebay for around $10.00, just attach it to a table or 2X4 . Do a search for industrial sewing machines.