Second hook in hook

[Julien]

Hello,

Could you help me to understanding one shape on hook ?
i don't undersant this part on some hook (in red picture below)  ?

Some hooks haveno things like that and work also...
Can't find videos in slowmo for understanding



Thank you if you have the anwser!

Julien

[Constabulary]

this hook helps guiding the thread - nothing special just a "thread guiding device". Almost all rotary hooks have this in one or another style.

Edited August 27, 2022 by Constabulary

[Julien]

Thank you Constabulary for your anwser

(picture below)
bleu helps guiding the thread but Red keep it until the end of the rotation of the thread , and sometimes if the tension is too much that creat a bad soon here also...
is it avoid to have too much tension against the fabric ?
are there some videos about it ?

Edited August 27, 2022 by Julien

[Josh518]

I'm also very curious about the  extra horn in red!  I reclaimed two used Mitsubishi 4170s and restored them.  One Rotary hook had the extra horn, one did not.  Both sew fine.  The Horn seems to keep the top thread loop tighter longer until it slips off of the horn.  It even sounds different when it is sewing as you can her it snap when it releases vs. the rotary hook without the horn.

But it is difficult to see any noticeable differences in stitch quality when sewing.  

Can anyone comment on the pros/cons of having/not having this horn?  I though it might have something to do with auto trimmers and the placement of the threads for the moving knife?

Surely someone must know!

[CowboyBob]

From what I have found is the longer "horn" is for thinner thread when sewing lightweight materials,size # 69 & larger works better without it.If you look & Juki 563,Singer 111w  hooks some have a finger on the gib that releases the thread later & the "heavy duty" hook does not & it will release the thread sooner which helps to pull up the needle thread for a better looking tension.

[Josh518]

Thanks!  Makes sense.  With #69 I can hear it "snap" as it releases which means it will not have consistent tension as it pulls - probably causing tension inconsistencies. 

[Uwe]

If the thread snaps off that “horn” or gib, then the hook is likely too late in letting go of the thread loop. The snapping may indicate that more thread is getting pulled through the tension assembly at the wrong time, which makes for bad or inconsistent knots.To fix this, you generally have to advance the hook timing a little bit (which then lets go of the loop a little bit earlier as well.)

One function of that horn/gib is to maintain control of the loop as the hook tip comes around the second time. Depending on sewing speed and thread thickness, that loop may get flung around pretty well after the horn/gib lets go of it. Keeping control of the thread loop a little bit longer as the knot gets pulled tight can prevent the hook tip (which follows very close behind that horn/gib) from accidentally catching the same loop again, which would cause a bind or break the thread.

Edited November 29, 2022 by Uwe