Detailed demonstration of installing a new vertical gear on a Bernina 730 sewing machine. Appropriate for technical sewing machine service people. Not a "do it yourself" project.
A huge thanks for this video! I just got my new gear and Im prepering for this operation on my 730. Ill admit Im a bit nervous but with the help of this video I hope it will be fine
Thank you so much for this video! I got a 730 for practically nothing due to the cracked vertical cam. A replacement part, a few hours of work and I now have a top notch sewing machine!
Sir, You're video is very informative, thanks for sharing. I'd like to make some notes though. I think that the gear replacement can be performed without taking out the whole vertical shaft. I think that just loosening screws that hold crankshaft and the gear would be enough to move down the vertical shaft as much as needed to take the bevel gear out. I know you probably did in order to clean everything from the "warnishing oil", but for otherwise clean machines the operation of completely taking out the shaft, crackshaft and the small h-shaped piece could be skipped, saving the subsequent hassles of putting back everything together. Thank you again
The only way that this is possible would be to remove the fixing screws on the hook crank and vertical gear while holding the hook crank in place and drop the vertical shaft down through the hook crank in order to set in place a new vertical gear. This would be a big problem to try and do and not at all practical. One would be dealing with oil varnishes causing one to force things, thus damaging alignment issues of the rack connecting rod, losing the stylus off of the lifting lever behind the hook crank. Best to do as suggested. To do it right, there is no short here. Believe me, I have tried it all over the past 49 years.
Sorry to get back so late. Yes, I used to do this but in these last years, the shafts in these older 730's make for a difficult job just to get apart due to hardening varnishes. When that happens, users making their own repairs often end up damaging the machine by forcing things.
Hi Neil my husband changed the beval gear on my Bernina 730 he doesn't understand when you tighten the screws , you said hand tighten them now he can not set the tention and thighten finaly
Hi Neal your videos is super informative I have Bernina 530-2 that was not in sync when I bought it! atempt adjusting return motion realiseed that nothing did line up, some clown online showed in a video to set return motion by alter on the hook crank but when return motion was right everything else was of I also altered the needle hook gear before I found your videos, Im looking for part two changing verical gear bernina where I hope you explain how to set up the machine after altered vertical gear but I only find part one Changing vertical gear. I hope you can help me locate that video. Greetings from Sweden.
Nope, the guy didn't understand the logic here. One cannot compensate one adjustment to make another one work. They are most definitely separate from each other. Loop lift (1) is the foundation of needle and hook timing. Return motion (2) is the gap distance between the needle and left side of the hook. The needle height (3) is the distance or position between the hook point and eye of the needle. The loop lift of the 530 series is preset in the factory and should not be messed with. It cannot come out of time by itself. Sounds like the machine is really screwed up at this point. Let me know
Thank you for this video! I want to repair a beautiful model 707 with a cracked vertical gear. But I have only found a replacement top vertical gear as a helical gear which would require a mating helical gear on the main horizontal shaft. I have not found a straight bevel replacement vertical shaft gear. Do you know of a source for the straight bevel gear for this application? If not, do you know where I can purchase a matching set?
Hey! Great videos! They helped me a lot. I would like to know where can I get the gear you are replacing in this video? Because I have the same problem
Thanks for your awesome videos Neal, much appreciated! Just wondering... I have an older 640-2-11 Favorit - are the vertical gear and cam stack gears in my Favorit interchangeable with/identical to the 730/830 Record gears? Thanks
No, they are different. 640 machines used straight tooth mitre bevel gears. This also applied to the early model 730 machines up until 1967. One would need to remove the main-shaft and replaced both gears with the newer helical gear sets.
@@michaelbujaki2462 Yes I have a Prusa printer and could do this but I want the machine to have a long life so PLA would not be my choice for a long term solution. I always print my parts out of PETG, but Acetal would be my choice and a lifetime quality material that can only be machined You never know what's ahead in the 3D printing technologies. Thanks much for your input.
It could be that the worm gear of the cam stack has developed a wide crack preventing the hand-wheel from turning freely. If this is the case, you should split the gear opposite of the crack for easy removal. Also, look at the condition of the vertical gear for any cracking..
@@amyd.5990 The problem on machines like the 730, 830 and 930 and subclasses is straight forward..."oil varnishes". Due to the precision of parts (very small spaces between moving parts) with any sticking residues prevent the machine parts from functioning. The needle position knob that will not position can have any one of the following parts or combination of parts frozen with residues: .... 1. the needle position shaft and stitch width axle ID, ....2. needle position piston detent and bore. .... 3. The stitch width crank slide, slide block axle, pivot axle, needle position link axle and bore. ....4. The needle bar frame's pivot axle, the needle bar driver link that is attached to the take-up lever, the pivot axle at the base of the needle bar frame where the connecting rod from the stitch width crank connects, and finally, the 10 mm slot in the main frame where the base of the needle bar frame swings left and right. I'm sorry miss Amy I have no simple solution but that is the logical order of discovery and repair of this device. I would start by loosening the 6 mm hex head of the needle position segment block and remove the needle position knob, clean the bore and knob's shaft with acetone and a Q-tip. See if that helps. Move to the next place and so on
