Deckel Fp1 . X-axis 1.5mm play

[Johan.A]

This sound intresting

SKC-60:
Slideway Coatings – SKC Gleittechnik

Maybe better if the nut is just little worn ?

My nut seems to be destroyd by someone or its a bad replacement

There is chuck jaws marks all ower it

I will try to give give Franz Singer an email . great advices

Thanks alot

 

[sigurasg]

If you order a new nut from Franz Singer, I suggest you order it directly and not via Ebay. Email him a photo of the current nut and the serial number plate of the machine. This will ensure that you get the correct nut and not the wrong one.

I second that - talk to Franz Singer directly. Also, in my experience, even if they don't have what you need listed on eBay or on their site, the odds are good they can pull it out of a hat on request.

 

[ballen]

This sound interesting
SKC-60: Slideway Coatings – SKC Gleittechnik
Maybe better if the nut is just little worn ?

Actually better to leave 1 mm around the epoxy. So put the nut in a lathe, and turn off most of the remaining thread. Then rough it up with a file inside. Clean carefully with solvent. Spray leadscrew with release compound. Wipe off compound, leaving thin film. Insert lead screw into nut, taking care to avoid or minimize contact. Block off one end of the nut using masking tape so that epoxy does not leak out. Fill gap with epoxy using a syringe. Hold vertical, wait for any air bubbles to rise out. Top off with epoxy, add masking tape at the other end. Then insert nut into a 3-jaw chuck on a lathe, center lead screw with tailstock and dead center. Leave to harden for a few hours. (Lathe only being used to ensure that the center line of the lead screw an the center line of the nut are the same.) Remove lead screw from nut/epoxy. Celebrate the lack of play.

This works well if the lead screw is not too worn. Cast the nut near the end of the leadscrew where the wear is smallest.

PS: alternatively, make a new brass or steel shell for the nut, and use that instead of the original nut. If you do this, make your new one a bit oversized (say 1mm). Then, after the epoxy material has set, but before you have tapped it free from the lead screw, chuck the lead screw in the lathe and turn down the outside of the nut to the correct diameter/dimensions. This will ensure that the outside of the nut is concentric with the axis of the lead screw.

 

[thanvg]

There is another good solution if you don't want to spend the money on a new nut. "Mold" a new nut around your lead screw using SKC-60:
Slideway Coatings – SKC Gleittechnik
Basically you remove the play between your existing nut and the lead screw by injecting low-friction epoxy into the nut, using the lead screw to provide the shape....

Do you have a reference for this procedure Bruce? I am aware of low-end applications, I don't think I have seen anyone making a nut like this properly.
Messing with old tools all the time something like this could be really useful.

BR,
Thanos

 

[ballen]

Hi Thanos,

here's a link to some English-language instructions: http://www.skc-technik.de/content/wp-content/uploads/2015/07/antifriction_coatings.pdf
The photos on page 19/20 are worth looking at.

Here is a photo of the last time that I did this, for a friend:

A few comments....

-- This is not from a metal-working machine. It's a four-start thread (!!!) from a garage door opener

-- You can see I have blocked it off with hot-melt glue. On the bottom I drilled a small hole which I used with a syringe to inject the SKC-60 epoxy. Air bubbles came out the top.

-- You can see a low-power (25W?) soldering iron clipped on. This heated the nut and epoxy to 50 or 60C. I used this to speed the curing process, and also to reduce the viscosity to help remove all air bubbles.

It worked out very well, still in use today.

 

[thanvg]

Thanks Bruce,

this thing has a minimum width requirement of around 2 mm (as I saw in the app note). Did you have to machine the nut a bit to allow for this?

 

[Peter from Holland]

You can also buy a tap(TR20x4 I believe) from Ali (€35)and produce your own nut from scratch
I have done so and they work great on bronze Even less endplay as a original one

If you just want a good nut I would not recommend the SKC route
Its a new thing to learn and good chance the first piece is scrap
If you want to learn a new thing I would say go ahead
I use SKC occasionaly to repare bedways and airbubbles are your enemy

Peter

 

[ballen]

this thing has a minimum width requirement of around 2 mm (as I saw in the app note). Did you have to machine the nut a bit to allow for this?

I think the 2mm is because they are worried about distributing the viscous liquid material to all of the slides and interfaces. If your slide is 2 meters long you need a couple of mm gap to push the liquid material all the way along. In such cases if you have less than 2mm, then you can't inject the material without bubbles and get a full distribution that pushes out all of the air. Here, with a small nut, and especially if you heat it as I did, there's no problem. So I think leaving about 0.5mm should be plenty.

 

[ballen]

You can also buy a tap(TR20x4 I believe)

Another option (if TR20x4 is the right size/thread): buy an inexpensive TR20x4 nut from Ebay, and epoxy or solder it into a suitable body:
Trapezgewindemutter Tr 20x4 Rg7 Rotguss Rechts DIN 103 | eBay

 

[Cycles]

If I recall correctly, the Deckel FP1 mills have an oddball thread size for their axis spindles and nuts, which made it complicated to reproduce in the homeshop since there are no taps in this size readily available. It was TR24x4 I believe, maybe someone else can confirm?

 

[Bill Fisher]

The leadscrew will provide the thread dimenions, and it's not difficult to fit a bronze sleeve into the existing leadscrew nut and cut a new thread on the lathe. With this thread diameter there is no problem with boring tool diameter.
Bill

 

[AlfaGTA]

I would make new....we be machinists after all...
Personally i would opt to single point it to get the fit that was best for the screw.
Just a piece of 660 bronze from the stock bin and off you go.
Cheers Ross

 

[Peter from Holland]

I would make new....we be machinists after all...
Personally i would opt to single point it to get the fit that was best for the screw.
Just a piece of 660 bronze from the stock bin and off you go.
Cheers Ross

A tap is cheaper as a insert and holder to do the job properly
I did not have these so I ordered a tap
I started ordering taps for crossfeed nuts Too small to single point (for my skills at least)
That worked great So I ordered bigger taps also
I do start it on the lathe set on the right pitch to get it all straight Turn it by hand
The nice thing is that all kind of od sizes are available as well as left hand

Peter

 

[Johan.A]

I agree that i could make one myself

The plan was to look if we had the right tool at work to cut the thread this friday
I only runs Milling macines and Wire edm so dont know everything we have

But I went sick so I stayed at home on friday. and sent an e-mail to Franz Singer.
I ended up order one nut from them .

If you guys look at my nut do you think it looks original ?
I dont .

They made several tries to drill hole for the locking screw .

Making a copy of a bad copy may not be good ?

And there is a oil pipe that goes down to the nut . There must be a hole in the nut for the
oil to come down to the screw . As it was the the oil pipe dident do anything good .



One more question . Arent nuts and leadscrews grinded on precision machines from beginning ?

Now on a old worn machine I dont see any problem making a nut myself . But isent it hard
to get the same precision like in a new machine if you turn the nut and leadscrew ?

Are there machines with less play than Deckel ? Aciera or Schaublin for example ?

I hope to get this machine good enough for my needs and then put a DRO on . I think
its nesaserry with old worn machines


Anyway I like my old machine and the Fp1 design

 

[MikeLDN]

Peter,
Just one possible correction, thread is Tr24x4 ?

(or different machines have different threads...?)

Ivan

 

[Peter from Holland]

Yes TR24x4
Thanks for that

Peter

 

[MikeLDN]

Hi guys,

I have also started to disassemble my X-axis parts.
After removing pin from left handwheel (looking from machine front), I can't remove it easily.
Is this right or left thread or just some cone fit?

Thanks

 

[MikeLDN]

It is just a straight shank.
One can expect that it will be harder to pull it, 80+ years old machine :-)

 

[Johan.A]

Thanks for all cinde help .

The play is much less now with a new nut and seems to work fine

Johan