I have a a rite adjustable tension bobbin with a a long, 7.5 cm. tube which is also very small in diameter. My question: my bobbin threader, the red bead head type, will not go into the tube because the of the narrow ceramic? tube. How do I thread the bobbin? Ive tried the old tried and true “sucking the thread down the tube”, didn’t work? Any suggestions?
Northwoods
Northwoods,
Almost all of my bobbins are the Merco Rite bobbins, great tools to use.
Go to your local grocery store or pharmacy and in the dental care section you will find a packet of dental floss threaders. These blue colored threaders are fantastic to use for threading bobbins.
A huge plus and I mean a HUGE PLUS is that they will not damage your bobbin tube like the metal/wire threaders will. It would be best if you set those wire ones off in a corner along with other antiquated objects.
Larry 
—sagefisher—
Do what Larry says… and if you find they won’t go through…as I have found with my Erich bobbin…just cut a pointed taper in the stem.
If all else fails, thread a needle, and then drop the needle through the bobbin tube.
TL
MC
double up a piece of 4# test mono, slip it thru the bobbin tube just like you would a threader.
Larry,
A huge plus and I mean a HUGE PLUS is that they will not damage your bobbin tube like the metal/wire threaders will.
You believe metal/wire threaders would damage the inside or edges of these ceramic tubes? My understanding, also from talking to the company owner, is that the tubes are pretty bombproof.
That said, I support the nylon threader suggestion 
Cheers,
Hans W
Thanks guys for the suggestions. I used a blue floss threader and it worked great.
another problem arose, It breaks the thread every time the unwinding thread bobbin is getting thread from the edges of the spool of threa. I even tried some 3/0 thread and sure enough when the thread was being drawn from the margins of the spool it was cut right where the thread goes into the tube. Its metal at that end not ceramic. I examined the end under a ver strong magnifying glass and couldn’t see a burr etc.
Any suggestions. If I cann’t fix it I guess I will chalk it up to a poor design?
Northwoods ( where spring may have arrived?)
Firstly, if it is a “Rite” bobbin holder, it has a ceramic tube;
http://www.ritebobbin.com/bobbin-models.html
(except the “mag” saltwater bobbin holder which is apparently surgical stainless steel, and is the only one with a 3" ( 7.5 cm ) tube.)
I have seen quite a few bobbin holders like this which cut the thread at the bobbin side, ( but not Rite!) It is poor design. You need a bobbin holder either with a ceramic insert at both ends, or a complete ceramic tube.
There is a way to fix it, but it is a bit of a finicky job. Get a smooth glass bead, mount the bead on a needle ( or similar) of appropriate diameter, ( this is to keep the bead aligned), now very carefully put a smear of good superglue around the metal tube, and lower the bead onto it.
It is also possible to countersink the area with a fine drill, ( or indeed a small sharp countersinking bit) in order to make the bead sit better. This will solve your fraying problems.
It is of course better to get well designed and good quality bobbin holders in the first place.
If it is a “Rite” bobbin holder you have, then send it back and they will doubtless replace it. http://www.ritebobbin.com/guarantee.html
TL
MC