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Machine Make a precision spindle.

Machine
incredible work, mcguyver, very inspiring... thanks for taking the time to write-up and share your knowledge with us!


maybe a stupid question but did you ever consider remaking the spindle with plain bearings? do you think that would have been any easier (or just different)?
 
mjautek said:
incredible work, mcguyver, very inspiring... thanks for taking the time to write-up and share your knowledge with us!


maybe a stupid question but did you ever consider remaking the spindle with plain bearings? do you think that would have been any easier (or just different)?
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Thanks!

I'm a big fan of plain bearings. The can deliver excellent performance. Consider the humble watchmakers lathe, tons of them around, plain bearing, 100 years old, zero wear and virtually no run out. One of the top of the line DSG lathes, the T17 had as a option plain bearings for the lowest possible runout and few rolling element bearing lathes match the performance of say the Holbrook B8, Rivett 608, many of the Schaublin 70 and 102's (and many more, those are just what came to mind).

Nothing wrong with plain bearings, but .....

1) I'm not sure it would have been easier. You still have to create the accuracy in the parts and now you're adding the complication of tapers. I just finished reconditioning a Schaublin 70 including regrinding the shaft and making a new bearing - the double taper style. THAT was a job I vowed not to repeat. Without designated fixtures and grinders like the manufactures had, it was next to impossible to get the male and female each with two adjacent tapers mating perfectly. This is assuming the double taper (3 and 45) is how to come at it. It has had incredible success so I probably would have thought that's the preferred arrangement and it is just really hard to create.

2) secondly, in a mill, you have to have to deal with thrust in both directions. That adds complications. The way lathes do it is ok, often just with a plain bearing thrust washer/bearing, but I figure a mill would have more force pulling on the spindle (for the helix on cutters) than a lathe. Arrest things up top via the original AC's could be problematic as the shaft will expand when warmed up. That doesn't matter with the needle bearings that could move a bit within the housing, but its quite an issue for a conical bearing where you're then pushing the shaft out of contact with the bearing.

Once I figured out I could fit low profile AC's I didn't spend much time on plain bearing arrangements, although it is a worthy approach to consider. Maybe it could work, the above are just my thoughts on why I went toward cartridge bearings.
I had this fantasy of owning a machine like that some day. Not I'm much less certain. HaHa.
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I hear you. Who am I to criticize the likes of Deckel and Aciera ..... but nevertheless, imo, its a horrible spindle design. The rest of the machine is just so bloody nice its worth it. Mine is silky smooth with no discernible wear, something that is a factor in deciding how much effort to put into them. What I'm unclear on is why the rest of the machine seems to have no wear, but the spindle was gone. They are highly sought after, asking prices of like 10,000 eros.

I wonder how many check and understand the potential spindle complication? Maybe I just got unlucky and most others are good? Everybody indicates the tapered bore which checking out a machine which in this case had very little runout ..... but this was because of the AC's at the top of the spindle. A bit of lateral force moved the business end of the shaft .003"!
 
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Great machining and problem solving. Thanks for taking us along for the ride.

I didn't really realize how small these mills were until some of your photos showing the sense of scale.
 
Mcgyver said:
I hear you. Who am I to criticize the likes of Deckel and Aciera ..... but nevertheless, imo, its a horrible spindle design.
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I simply can't resist commenting on this......

They would have paid you a king's ransom to go and work for them....... But you would have said no because you had more important dreams and prolly couldn't tolerate their work culture anyway. And that is why it's a horrible spindle design..... It's all your fault! LOL!
 
Mcgyver said:
Nothing wrong with plain bearings, but .....
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Thanks again for your thoughts! come to think of it, it's pretty incredible that you've rebuilt both a plain bearing spindle and this one with roller bearings.


As for why deckel did what they did (and also why plain bearings came to mind) - the fp1 had plain bearings in both horizontal and vertical spindles from 1933(?) - 195x (?) so I wonder if the ground-in bearing races was done to keep the same form factor.

Also I wonder if it's not really a problem if people keep up to date on maintenance. the deckel manual says to dismantle and regrease the spindle every 3-5000 h, I'm sure most people never did...

one could argue that the design is good enough - with some care it will last the "lifetime" of the machine. I wonder if the designers and factory workers ever considered that their creations would be cherished by people like us 50-70 years after the machine was built...
 
mjautek said:
Thanks again for your thoughts! come to think of it, it's pretty incredible that you've rebuilt both a plain bearing spindle and this one with roller bearings.
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Here's a bunch of shots of the plain project. What made it so difficult was the double taper

It was too much, next time I scrap the damn thing instead of scraping ..... I get tired just looking at the photos lol

www.metallum.shop

Reconditioning a Schaublin 70 - the Headstock - Metallum

Return to Projects Reconditioning a Schaublin 70 – the Headstock Reconditioning a Schaublin 70 – Intro the Tailstock the Bed the Headstock the Slide Rest the Headstock A diminutive project of king sized proportions. It must have been run dry because the condition of the spindle bearing and the...
www.metallum.shop
 
Mcgyver said:
As the photos are messed and I can't edit posts (grrrr) here is most of the content posted on my web site.

www.metallum.shop

A New Spindle for an Aciera F1 Mill - Metallum

The Aciera F1 is one of the nicest small mills ever made, but the spindle design is terrible. The inner race is the shaft and out the housing! Wear means its scrape. So I made new one
www.metallum.shop
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Thanks for giving us access to the pics! Reading through now, amazing work!!
 
Mcgyver said:
This will be long. If it seems long to you, it was a friggin marathon for me. Probably the most difficult thing I've made and now its done! yippy! I'll do this in several posts, more tomorrow.

A decade ago I bought an Aciera F1. Before the deal was concluded I managed detect that the spindle was in serious trouble. No runout, but you could move it several though by applying lateral pressure. At the time I had no idea what the bearing arrangement was, or I probably would have passed. Instead I negotiated a deep discount for the pooched bearings and the machine came home with me.

The bearings at the business end are needle bearings with the shaft being the inner race and the housing being the outer race. Deckel used this on some mills as well. What it accomplishes is a very robust spindle with a relative small diameter. It is also in my opinion, the poorest spindle design of all time ..... bearings are a wear part with a service life and with this structure, instead of just replace a bearing, the whole spindle is basically toast.

What to do. There is a place in Germany that wil`l rebuild it. Thousands of dollars. They regrind the surfaces and make or buy needles of the precise sized needed for the new dimensions. Yuck.

Instead I started designing and found with some creative use of threads and mixing in some imperials bearings with super precision AC's, I could just make a spindle that would accommodate the required OD and collet. With a limited range, the challenge is have all the steps you need along shaft and spindle and still having enough room to fit a bearing.

Forlorn and spindless.....


View attachment 49151


Rouging out the spindle housing

View attachment 49152


I used preharded 4140 for everything. After roughing, I ground it


View attachment 49153


Then some long drilling

View attachment 49154

more to come....
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Is this The Mcgyver I lent my Machine Toe Lifting Jack too? Just joined this Group Today. Merry Xmas
 
Mcgyver said:
As the photos are messed and I can't edit posts (grrrr) here is most of the content posted on my web site.

www.metallum.shop

A New Spindle for an Aciera F1 Mill - Metallum

The Aciera F1 is one of the nicest small mills ever made, but the spindle design is terrible. The inner race is the shaft and out the housing! Wear means its scrape. So I made new one
www.metallum.shop
Click to expand...
Great work.
 
Tool Room Mike said:
Is this The Mcgyver I lent my Machine Toe Lifting Jack too? Just joined this Group Today. Merry Xmas
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Madman? great to see you are still bobbing and weaving - here's the toe jack I built from it with due credit lol. Good hear from you and let's see some of the things you're up to

www.metallum.shop

Projects - Metallum

A collection of diy home shop projects I've been working on including machining, 3d printing and machine tool reconditioning
www.metallum.shop
 
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