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FP1 Z Nut Sources

tommybees

Plastic
Joined
Aug 9, 2023
Hi Folks,
I am unexpectedly working on a new to me imported to US FP1. It was reported in good shape at the time of sale... not so with all kinds of issues such as gibs found to be loose, damaged and worn with heavy oil, but it at least it felt smooth.

Everything has now been stripped, cleaned and inspected less gear boxes. The gears seem to be ok so I will just drain the heavy gear oil, rinse and replentish for now.

The biggest non operational issue looks to be the z nut and am asking for help to find a spare or source to at least make this operational. The attached photo is not perfect, but the bottom half threads are mostly shredded. It seems Singer no longer ships to the US and after spending a few hours searching, including German Ebay, I have not had any luck. Any advice/leads would be appreciated. I dont have a metric gear set for my lathe and so my best option seems to be to purchase a nut if possible(and quickest).

Other disappointing finds were badly scored ways and a crazy attempt at a mogalice (sp) repair on the Y gib. 50% of the Mogalice was shreaded into bits, making what felt like a black greasy sandy paste. The gib was hit with a hand grinder prior to bonding and is overal all it is a real mess. The mating surface is worn, but not badly scored. In the long term this situation is repairable. Other oddities include some non fitting parts and what looked to be all new yet unlubricated totally dry to the touch x/z gears with some very large dolops of bronze laden sludge around the clutch. The X axis nut looks ok and hoping they just slammed in a new nut with no cleaning! I guess this hunk of iron was a bodgy rebuild of donor parts and I hope to at least recover some function.

Thanks in advance!

PXL_20240127_192624334.jpg
PXL_20240126_025439364.jpg
 
Well, the plot thickens...and as probably expected by many of you, the x axis screw is FUBAR'd in the middle section. Not sure how I missed it, but with the good looking nut I did not notice the male threads do not even resemble an ACME profile, even from a distance. The brand new looking x nut was put in to hid the x travel backlash. In fact all axis reported respectable backlash number including the spindle prior to purchase! Those tool resellers are a crafty bunch aren't they!

And it turns out the Z axis threads are not great on the load bearing side. I inspected it with a good 20x loop and can see it will damage any new nut in short order. I guess I should add a gas shock to reduce the load for the time being while I sort out options. Maybe I should come up with a nut insert strategy with a generic ACME tap and make some replaceable threaded insert sleeves into the original nut body until I can wrap my head around a proper fix. Change-outs would be fairly quick and cheap and the z axis has a natural preload so it does not have to be perfect yet still function exceptionally well.

Does anybody have success or know of a link with said success in adopting a ball screw/nut config for the x axis? It is a shame to damage the new x axis nut, but I am not sure it will be cost effective to try and get a proper screw. The z will have to stay ACME... Thoughts are welcome including calling me an idiot for importing this beast.
 
Strange about Singer not shipping.
Got some parts delivered from him just this week.
There is a member here that used to have some FP1 spares.
Posts under the name” wrench”
Not seen any posts for some time. Perhaps he can be contacted via private message or e-mail.

Also FPS currently builds an FP1 reproduction, so they must have parts for their offering.
Might be an option.
Cheers Ross
 
The European screws are not “Acme” but rather trapezoidal. So you can’t just buy some precision Acme rod and make up a replacement screw.
You need a pair os nut and screw together.

As to going the “ball screw” route, I would advise against it. Ball screws have the charsstic of “running” when any force is applied( cutting metal).

Sorry about your difficulties and the seeming poorly turned out machine, that really sucks.

Think that you could apply “Turcite”or “Rulon” where the “Moglice” failed.
Would require scraping of course.
I can recommend a local ( SF Bay )
Scraper that I have used.

Cheers Ross
 
Thank you for the comments and leads Ross, you are always helpful to everyone, especially so to new comers like myself.

Ill reach out to Singer direct (the EBAY site says they are not shipping to US) and as for FPS, just checked out there site and see no prices:(, a good lead none the less.

I'll stay away from ball screws as suggested, it makes sense what you say. I now wonder about trying to cobble together screw/nut combination vs biting the import bullet from Germany. After a little more googling, the thread dia's and pitches do not seem standard combo's as listed in the US catalogs... the long journey to making chips begins. On the other hand, I travel to Germany every 3 month or so....maybe something to take advantage of.

Ill post updates in a month or so as parts (I hope) arrive for others that might find themselves in the same saga.

BTW , I am in the South Bay, a minor hobbyist...maybe one day we will meet!
 
Just a few questions to help align potential solutions with your capabilities.
Do you have a lathe, if so how big, is it capable of doing metric pitches?
Metric tooling( taps/dies, hand tools ?
Good range of measuring instruments, test indicator, etc.
Do you have lifting capability ?
Hope to hear more positive posts from you in the near future.
 
Here is a link for the scraper hand.
Guy I have delt with is Merck.
He may be retired now, but I think his son also worked there, might be the current lead guy.

Have a look here, member selling some FP1 parts.

Cheers Ross
 
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Hi Ross,
Yes to having lathe, but in inches and food set of tools, measurement and lifting stuff. I can coble any other items needed, except probably a proper size surface plate. I am at 18x18".
(Edit) Lifting is limited, maybe 500# and not mobile.
The OEM level replacement looks to be extremely expensive and so any moderate investment in further tooling is warranted.
BTW, I have already a suitable DRO set on hand and will have that as the main feedback. If I have to diverge, I could go with a different nominal lead on each axis.

Also, I will ping the Belmount gentleman ...seems to be a long shot, but who knows.

Thanks for helping rallying around this!

As for thread type, it seems metric lead are all trapezoid and English are true ACME, do you concure.
 
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Interesting to find that Misumi has LH 25-5 threaded bronze bushings. They also sell the 25mm LH leadscrew for about $100 but no mention of fit spec or how it is manufactured so maybe great or maybe poor backlash, but certainly 100x better than what I have and for not too much investment to make something functional. Not so much luck yet for 24mm LS sourcees.

For now, I plan to bore out current damaged threads on the Z nut, turn down the OD of bushing to keep some original wall thickness and press and pin the bushing in place. Ill shoot for H,N fit, and maybe LT for good measure. In all cases, I intend to make it replaceable and take advantage of a $47 nut for the near term... like so. The replacement is shorter than OEM, but again, short term seems to be a good solution.
1707337366019.png
And then depending on quotes, I plan to order both 24-4RH and 25-5LH 500mm long threaded rods and socket fit & pin the working ends of the original parts to the original key and threaded interface ends. The pins have to be inset below the running surface or should I just silver solder?

The Z shaft is pretty straight forward. I have even thought about lopping off the original threaded section, flipping it 180deg and socket'g it back on to the original interface end so that "good" thread bears on the new nut. I will loose 25mm or so in length and be short at top travel (not so useful anyways), but with the cheap nut, I think I will live with the risk of lower life of nuts in the future. Oh for anybody reading or plans for something similar, the top Z securing nut is standard M18 so should be 22mm wrench, not 23mm as noted in some other threads.

X axis is a little more tricky since both ends need to be lopped off and a slot added back thru the threads. This axis came with a brand new nut and is what hid the fact that backlash was quoted as being good as new. Damn those resellers! The steel threads a pretty badly worn and so I have to fix this first. Again, dam those resellers.

Any thoughts of what to watch out for and past experiences if attacked as noted? Obviously coaxial interfaces are required and think Ill rig up a grinding wheel to face off the shoulders to match and then light press together.

I have also reached out to Rempco Inc. to see what prices might be to salvage/refurbish shafts if I send the parts to them. Anybody have luck with them?

Finally, started on the rest of the rebuild. These Deckel gibs are very hard, with interesting carbide or martensite inclusions. My carbide scrapper was abused and had to be resharpen multiple times. The gib was bowed and twisted and so took a lot of effort to scrape back flat - done. The gib extension on the right side of the next photo will be interesting to some. Bonding of the Turcite is next. I have .8mm thick Turcite and calculated that this is equivalent to about 65mm of gib allowance. If everything comes in as expected (original wear, gib scraping, dovetail scraping), I should only have to scrape about .4mm of Turcite away.
1707338970821.png
...And original gib drama with epoxy filled repair before scraping flat.
1707342486188.png

And here are the Y dovetails surfaces. There was enough backlash in the y axis lead that I hope this scraping will not cause gear mesh issues! I just barely scraped to the wear grooves and there are a few wear grooves still remaining towards the front/right 10mm or so. In this case I scraped down bit by bit to lower the surface in a parallel fashion from original surfaces. If there is still some gear mesh margin, I may take this surface down a little more, but stopped here for now.
1707338338774.png

Comments are welcome!
 
Thanks but link did not work, do you have any further info?
Hopefully only one nut is needed in this configuration and then longer term a matched nut and screw is the goal. If the wear rate is too high, then tap and bar stock is definitely the way to go...but I hope to go down final route sooner. I will still check into it further, but first estimate for two self made nuts, the cost would be about the same @ ~$50 each. If 3 are needed, then the benefits start to appear @ around $35 ea vs $47 each for pre-made from Misumi.
 
Also I am not a fan of turcite on these machines
Hard to shield it from debries which eat the turcite
I would put a shim on the back of the gib With a hole or groove for the oil supply

Big grooves/scratches you can fill with a epoxy, like moglice (SKC if you were in Europe)
Grind a shallow undercut with a dremel Apply carefully not to create bubbles
And then scrape

Peter
 
Just a point, no need here to have to use a trapezoidal thread here since the OP is going to replace both the nut and the screw.
Conventional Acme will work just as well.
Go with what you can purchase that fits your budget and mechanical needs.

Cheers Ross
 
Just a point, no need here to have to use a trapezoidal thread here since the OP is going to replace both the nut and the screw.
Conventional Acme will work just as well.
Go with what you can purchase that fits your budget and mechanical needs.

Cheers Ross
Yes Perhaps so But it would be nice if the dails were right
And no cheap Acme taps to be found on Ali
I have several of those taps And they work great on bronze
Less endplay as a original Singer one in fact

Peter
 








 
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