Constabulary

I cannot imagine the foot lift lever is worn so far down. Post pictures and / or a video (upload to YT and post a link here) please. Maybe you have wrong tension discs installed which put the "release cup" to high. I had this with an Adler 30. The added washer may be the problem as well. There should just be a thin felt or leather washer under the tension discs of approx 1mm-1.5mm thickness. worn gears and racks are a problem with these century old machines. You cannot adjust the hook timing as they have no timing eccentric like the later 29K models.

not sure how the casting on the later class 17 is shaped but the old 17 shares the face plate with the Singer 16 which sometimes can be found cheap.

since it is a (more) modern clone of the singer 111G / 111w I´d assume it is mentioned in the manual. I´ll check my records. EDIT: Not sure if the 563 is entirely the same but this extract is from a Singer 111 manual - hope it helps

what needle and thread size are you using? Some pictures or a video may help to figure the issue. EDITED

indeed looks like a beefier version of the BUSMC A1. I owned an A1 several years ago:

are forward and reverse stitch length equal or is the reverse longer - probably.

afaik its the same as on other 29Ks too EDIT: Parts list > Parts number > check google Parts list: https://archive.org/download/manualsbase-id-577992/577992.pdf Parts number: 544383 For instance: https://marfar.com.au/products/screw-needle-clamp_-or-545318-544383-or-happo-46642

the reason likely is that clutch motors are way outdated nowadays. On my side of the pond you sometimes find 750w Servo motors for about 70€ (not kidding) but that of course is super cheap. Anyway you find proper servo motors for 120 - 150 € or $ so for me I see no reason not to replace a clutch motor that needs service or maybe bearings with a energy saving servo motor. But that's just me. If you want to invest work time and maybe money into an old clutch motor go a head. I would not do that. Just my 2 cents.

its a 31-15 not 30-15 and is a tailoring machine not a harness machine (except for Barbie & Ken horse harness - maybe **kidding**) and what is the number? looks like the check spring in the tension unit is not original and the tension unit seems to be set up incorrectly. I´d get a new spring or complete tension unit. And you better download a manual. Neither 134LR nor 135-34 is the needle for the 31-15 except someone set it up for one of the two. But you have to figure that, hard to tell from the distance. The original needle was / is the needle DBx1 / 16x257 Maybe this helps: https://leatherworker.net/forum/topic/74484-what-needle-size-do-i-need-for-my-singer-31-15/ https://www.google.com/search?q=needle+singer+31-15+site:leatherworker.net&client=firefox-b-d&sca_esv=1cdd3e2116a3bced&sa=X&ved=2ahUKEwi1ndrztsiLAxUF-gIHHUjaKFIQrQIoBHoECBUQBQ&biw=1600&bih=719&dpr=1

The the friction between leather and the rising needle lifts the presser foot. I´d increase the foot pressure first. If it does not help look for a heavier spring for the foot bar.

The Seiko TE-6 head section is pretty much the same as on my former Singer 34K5 (Singer 16 type so to say) which I have restore and later it had an accident and I had to replace the needle bar. I have used a Singer 17 needle bar which is the same as the Seiko and it worked. I used 135x17 needles though the shank is thicker as on Singer 16 needles - it just worked with the new needle bar back then. Just my experience but I no longer have this machine I have replaced it with the Singer 51w. I would simply try a different needle and adjust the needle bar height. Just hand crank it and see what it does. https://leatherworker.net/forum/topic/66729-singer-needle-bar-i-could-use-some-help/#findComment-434368

Google: https://www.google.com/search?client=firefox-b-d&q=needle+singer+51w

ebay: https://www.ebay.de/itm/152425997655

not sure what you mean with needle hook clearance? You mean the distance from the needle to the hook tip? If you mean the rise from the BDC to form a loop then 1/16" is not enough. Machines with 328, 214 or 216 needles usually have a rise of 3.5mm - 4mm from BDC.

if you have such information why not sharing it in the public forum?

okay got you - so I think a Singer 78 / CONSEW 28 could be a choice. They have no feed dog and a slotted needle plate + needle feed but it is not jump foot machine. Feet work as on triple feed machines. So just a suggestion. But parts & feet are rather hard to find.

wondering why you are focused on a jump foot. Why not triple feed like the Singer 111W156 / 111G156, Juki 563 or similar as Pfaff 145 / 545 Adler 67, 167, 267 and so forth...

could be a bent needle, bent needle bar or a worn out needle hole in the needle bar - just guessing. I would try replacing the needle bar .

this: https://www.college-sewing.co.uk/accessories/chair-stands-table-tops/machine-support-rest-pegs.html

150 is a steal. I´d buy it in a heartbeat.

The FERDCO seems to be a SEIKO STH-8 of some kind - seems it has a heavier hand wheel. https://www.seiko-sewing.co.jp/en/products/sth-8bld-3/ I know nothing about Union Special machines but it looks like a high speed tailor machine

I guess it is ALEXA compatible too. Alexa: sew me gun belt... no... guitar strap... no... ahm... sew both and make me a coffee... no... chai latte Answer: Yes, I will sew a strap on your Chai Latte and make a coffee colored gun belt for your guitar.

wondering if there is a hand cranked version of it

as far as I know the singer attachment screws fit: https://www.ebay.com/itm/143367841409

main question from my point is what do you want to do with the machine? Just darning I guess cause the machine has no feed system to feed the material for achieving a constant and equal stitch length.