I tried getting an email out to you to ask questions about my Viking but I can't get that account working on this end.
Anyway, this machine started out working well but took a turn for the worse. It was bunching up in the bobbin box and breaking the thread. First I thought the timing was off on the hook, but after watching it manually, decided that wasn't the issue. There is a Viking Village in Virginia so I gave him a call. He thought the bobbin box cover was too tight. I didn't know the importance of this and had the three screws turned all the way in. Turns out that that is wrong. Those screws are supposed to be loose, and how loose each screw is, can be hit and miss in getting it right. I loosened the screws (half turn each) and it helped, but I was still breaking thread. I tested my thread and it feels weak. On top of all this, it didn't like the needle I was using. So, it appears that this was all a combination of things causing these issues. No problem having a broke down machine for a while because I had my White, but I am still wanting the Viking as my main machine. You can really see how well these were made compared to today's machines. I will keep picking away at it 'til I get it right.

Well, sounds like trouble.

When I am adjusting my bobbin case I am VERY careful not to tighten or loosen more than a quarter turn at a time. You might check - if the bobbin is too full of thread - it will not feed well and if the needle is not big enough for the thread to move easily through - that causes problems. Usually, I almost NEVER change the bobbin tension unless it is having big problems.

If it will not sew correctly - I start by rethreading the entire top and bottom, check the needle, then check how the thread is put into the bobbin case - there is a correct and wrong way.

I just got my third machine - my sister found one in Arizona at a garage sale - $25 - so if I have to get it fixed a little it will not be bad. There is a Viking dealer in Plymouth (northern Mpls. suburb) who does my repair work.

If you are having trouble let me know I might be able to help to get your machine in.

email sent
do you have the manual for the 6440? I just found mine. I could scan and send if you need it.

Yup, I am learning about that bobbin case. It is unreal how on a Singer you just snap it in with the turn buttons and you're done, yet this one is much more touchy. Oh well, once I get it right, I'll know to leave it alone, or adjust in tiny increments.
As far as threading top and bottom, I did have some problems when winding bobbins. The thread coming off the spool would want to kink up (older one pound spool, taking off the top) while winding the bobbin. So coming off the bobbin more or less had the same problem (the tail would be all kinked up. I knew that this was part of my problems so I ordered new thread from Dan.
I know not to overfill the bobbin so that isn't an issue.
I downloaded a manual so I have that as well.
Thanks for the tips... I'll keep you posted. Might be a while because waiting for thread and needles, and I'm busy making another titanium stove.

Portage Keeper, When making your winter shelters, which seam do you use to join the top and side panels. Also what works best for you when Installing zippers. I'm planning a packable 1 person shelter for fishing.
Looking forward to seeing your take down Ti stove. Your first stove was Impressive.

quote wingnut: " Portage Keeper, When making your winter shelters, which seam do you use to join the top and side panels. Also what works best for you when Installing zippers. I'm planning a packable 1 person shelter for fishing.
Looking forward to seeing your take down Ti stove. Your first stove was Impressive."

I always use a flat felled seam as it is supposed to be one of the strongest seams.
I use coil zippers as they withstand packing/unpacking the best without damage. I use double two way zippers so I can zip down from the top for either better ventilation or just to peak outside, or bottom up for entry/exit. For cold weather on a shelter for fishing I'd use a #8 as it would hold up better and has larger tabs to grasp with gloved hands. I don't recall for sure, but I believe that tooth style zipper hold up best if they ice-up.
My pyramid shelter had a sloped entry so I just left the zipper teeth exposed and installed a zipper flap to shed water. On the shelter that I just finished, the entry is straight up and down so I didn't install a zipper flap, but I did crowd the fabric edges to the center of the zipper. I didn't use a zipper foot on the machine on this last one because the zipper tape was wide enough to stay away from the teeth. Otherwise you may need one.
I can guarantee that Grandma L has sewn MANY more zippers than I have and maybe she has some helpful words to offer.
Good luck on your project.

Sounds like you have a good zipper process. The key is function and you have that nailed!

I'll have to give the flat felled seam a try. The zippers on the shelter that I tow in are curved. They go from horizontal to vertical and opens the bottom of the panel completely for easy access. I'd like to make the packable shelter the same way. Thanks for the reply.

quote wingnut: " I'll have to give the flat felled seam a try. The zippers on the shelter that I tow in are curved. They go from horizontal to vertical and opens the bottom of the panel completely for easy access. I'd like to make the packable shelter the same way. Thanks for the reply."

I the curve is not sharp - the zipper should go in easily - if it is sharp and thus more difficult - you could put on 2 zips - one horizontal and one vertical.
Too bad you guys don't live closer - I would really like to see your projects. It would be fun to build a big winter tent - but I have no need for one so-- I should find someone nearer home to help with theirs.