Proper bearings for a mill spindle rebuild?

Bakafish · Tuesday at 2:36 AM

psionik said:
How should I see these statements, if not discouraging?

No strawman, direct quotes:

...

I've stated that I might alter the design because of the possibility of moving to CNC and a higher speed spindle. What I'm interested in are bearing considerations. Instead of straight answers that gave me some info I didn't already know, I received the above.

Not to discount those who have been helpful and encouraging. I appreciate you. I just wonder where all the nasty attitude is coming from. Perhaps I go about life differently than other people, but I am the last to be discouraged, and that is the ancillary point I've been trying to make so that we can get back to business.

Even with your cherry picked partial quotes I was nodding my head in agreement with them. The attitude is that everyone here has been through this all before, a guy with a lot to learn, barging in full of piss and vinegar with big ideas demanding answers. Ideas that are neither novel nor practical, but are common pitfalls that any relatively intelligent person might make before gaining the knowledge and experience to understand their weakness. It is natural for us to try and cut to the chase, we said so as gently as I've seen (good work guys) and the fact that you are not accepting of it shouldn't really be a surprise given your nature, but it's there nonetheless.

If you want enablers cheerleading your tomfoolery, I'm sure we can oblige. I think the first air bearing Bridgeport is something only you could accomplish.

psionik · Tuesday at 2:57 AM

Why must my ideas be novel or practical?

I'm only trying to have fun.

I've demanded nothing. Participate as you wish.

I know I have weaknesses. That's why I sought tips from others (though not to give up before trying)

My nature? Why are you making it personal?

"Tomfoolery?" Who are you to judge what's worth my time?

I am going to put this thread down now and walk away, for everyone's sake.

smh.

Tyrone Shoelaces · Tuesday at 3:46 AM

psionik said:
Why must my ideas be novel or practical?

I'm only trying to have fun.

I've demanded nothing. Participate as you wish.

I know I have weaknesses. That's why I sought tips from others (though not to give up before trying)

My nature? Why are you making it personal?

"Tomfoolery?" Who are you to judge what's worth my time?

I am going to put this thread down now and walk away, for everyone's sake.

smh.

Because essentially we are professional, practical, people on this site. We aren’t dilettantes. Most of us haven’t got time to waste. We go straight to the most sensible and cost effective solution, anything else is just posturing. You aren’t the first guy to come on here trying to re-invent the wheel and you probably won’t be the last.

Regards Tyrone.

mottrhed · Tuesday at 7:46 AM

Bakafish said:
Even with your cherry picked partial quotes I was nodding my head in agreement with them. The attitude is that everyone here has been through this all before, a guy with a lot to learn, barging in full of piss and vinegar with big ideas demanding answers. Ideas that are neither novel nor practical, but are common pitfalls that any relatively intelligent person might make before gaining the knowledge and experience to understand their weakness. It is natural for us to try and cut to the chase, we said so as gently as I've seen (good work guys) and the fact that you are not accepting of it shouldn't really be a surprise given your nature, but it's there nonetheless.

If you want enablers cheerleading your tomfoolery, I'm sure we can oblige. I think the first air bearing Bridgeport is something only you could accomplish.

OOO, maybe driven by a pmac motor, thats powered by a wind turbine generator mounted to a generically modified rabid Tasmanian devil. Naturally this power distribution would be wireless after perfecting and executing on Nikola Tesla's theory.

Seems like you should start at the dna modifications for the little devil, theres gotta be a forum you can lean on for that. Then you can get to the unfunctional floating money pit later.

Rob F. · Tuesday at 8:30 AM

If you want to convert an old bridgeport (is it a series 1?) to CNC then just put the stock bearings in it and get to work on the cnc aspect. There will be plenty of work there. If the machine is clapped out then take one of Richard Kings rebuilding classes. That really will give you good skills AND enough work to last far into the future, then you might end up with a useable machine to be proud of.

BT Fabrication · Tuesday at 10:31 AM

psionik said:
What is not my goal is 3) To get this machine up and running with minimal hassle. Why? Because I have decades to kill and money to burn.

if you had $ to burn, you would have just paid someone else if it already existed in the market and you would have had a bigger budget then $1000........... any research says that singular bearings can cost that alone. if you were able to learn everything, you might have been able to learn that before asking the questions above.

JST · Tuesday at 10:55 AM

remember, the basic question is: "If I make an improvement to one part of the machine, is the rest of the machine good enough that the "improvement" (if any) can even be detected?".

So, if you are "having fun investigating" (I can totally understand that idea), you still need to have a decent probability that the results can be actually quantified, or the whole thing is pointless. Better head bearings are all very well, but an inaccurate spindle, or a head support system that is not sufficiently steady, for instance, can obscure the effect of the better bearings. You may be unable to quantify results, which means you wasted your time, effort and money.

That said......

All types of bearings (roller or ball, angular contact or other) are available in different grades. Angular contact and angle roller bearings are the ones most likely available in the best grades.

The best grades are actually only a little better than lower grades, but that is because the errors being chased are small. They are, however, disproportionately more expensive.

Choose wisely, since the reduction in errors requires much better surrounding structure in order to actually make an improvement. Equipment designed to accuracy around a thou or half thou is likely not going to be good enough in structure to reliably show up accuracy to sub-tenths, in use.

Richard King · Tuesday at 11:30 AM

I took an SKF bearing install class years ago and the instructor told us that modern bearing grinding machines were so accurate that class 7 angular contact bearings were the norm. He also told us that as they inspect the new bearing some are more accurate then others and they are marked class 9. They come off the same grinder on the same set up.

I am a rebuilder and I always installed precision bearings on precision scraped machines. I can see how if you have a clapped out machine that you will never rebuild. If the machine was new they installed class 9, but if the machine is worn, why spend the money on class 9 and just buy class 7 or 5. Installing the higher class bearing is a lost art too. Here is a You Tube show from SKF on 2 different ways of removing worn and installing new bearings. I was shown a similar movie when I took my class at SKF. I show this to my classes.

Tyrone Shoelaces · Tuesday at 11:59 AM

Richard King said:
I took an SKF bearing install class years ago and the instructor told us that modern bearing grinding machines were so accurate that class 7 angular contact bearings were the norm. He also told us that as they inspect the new bearing some are more accurate then others and they are marked class 9. They come off the same grinder on the same set up.

I am a rebuilder and I always installed precision bearings on precision scraped machines. I can see how if you have a clapped out machine that you will never rebuild. If the machine was new they installed class 9, but if the machine is worn, why spend the money on class 9 and just buy class 7 or 5. Installing the higher class bearing is a lost art too. Here is a You Tube show from SKF on 2 different ways of removing worn and installing new bearings. I was shown a similar movie when I took my class at SKF. I show this to my classes.

I’ve done it both ways. The old bath of whale oil and the modern bearing heater. I know which I prefer. I can still smell the hot whale oil now, 30 years later. Urgh.

Regards Tyrone

Richard King · Tuesday at 12:09 PM

I priced a cone shape bearing heater way back when and almost fainted. So I made one out of a 4" diameter aluminum shaft and turned a taper on it the small end was about 1/2" then I turned it around and drilled a hole in it. Bought a 110 v heat sink and slid it into the hole. I till have it in the shop. It works great. When I first used it, I used a wax pencil to find the temp. Different color pencils melted at different temps. Now I use an infrared temp gun. So so much better then pressing or tapping on a bearing.

Tyrone Shoelaces · Tuesday at 12:22 PM

Richard King said:
I priced a cone shape bearing heater way back when and almost fainted. So I made one out of a 4" diameter aluminum shaft and turned a taper on it the small end was about 1/2" then I turned it around and drilled a hole in it. Bought a 110 v heat sink and slid it into the hole. I till have it in the shop. It works great. When I first used it, I used a wax pencil to find the temp. Different color pencils melted at different temps. Now I use an infrared temp gun. So so much better then pressing or tapping on a bearing.

The SKF bearing heaters are very good. Quick, clean, and accurate. You just set it up, put the sensor on the bearing and press the bearing symbol on the remote. You can set the heater to higher temperatures than the standard 110 degrees. We used the one shown last in the video. The one with the two uprights and the removable cross bar.

Regards Tyrone.

mottrhed · Tuesday at 2:03 PM

We use induction heaters almost exclusively for bearing installation, knowing and taking advantage of the thermal characteristics of the different parts makes for a much easier assembly with better results.

I also can confirm many bearing mfgs pluck the best bearings for the higher class, and for the tight tolerance stuff you will PAY. There is no such thing as "perfect" if you think its prefect you just aren't looking close enough. Abec 9, still has runout, ball variations, and race variations, its just less than 7. This is before you stack multiple bearings together, add a shaft, housing, spacers, nuts etc etc. Its always only as good as the stackup of tolerances.

We can measure repetitive runout, non repetitive runout, thermal growth/drift in multiple planes, and much more down below a micron, below a nanometer, to a picometer, at up to 300k rpm. Theres no such thing as perfect, there are machines designed to do a specific task within particular constraints of cost/space/efficiency. With an improvement in a particular spec, many times there is a compromise, tolerance vs rigidity, etc

Richard King · Tuesday at 2:15 PM

mottrhed said:
We use induction heaters almost exclusively for bearing installation, knowing and taking advantage of the thermal characteristics of the different parts makes for a much easier assembly with better results.

I also can confirm many bearing mfgs pluck the best bearings for the higher class, and for the tight tolerance stuff you will PAY. There is no such thing as "perfect" if you think its prefect you just aren't looking close enough. Abec 9, still has runout, ball variations, and race variations, its just less than 7. This is before you stack multiple bearings together, add a shaft, housing, spacers, nuts etc etc. Its always only as good as the stackup of tolerances.

We can measure repetitive runout, non repetitive runout, thermal growth/drift in multiple planes, and much more down below a micron, below a nanometer, to a picometer, at up to 300k rpm. Theres no such thing as perfect, there are machines designed to do a specific task within particular constraints of cost/space/efficiency. With an improvement in a particular spec, many times there is a compromise, tolerance vs rigidity, etc

Mottrhe (odd name, lol)

Are you a new machine builder? Thanks for your input :-)

pmtool · Tuesday at 4:08 PM

One other thing to know is that the Abec grading system is not really commonly used to classify spindle bearings anymore. You will see P5, P4, P3 instead. Note it is opposite of the abec scale. Lower numbers are the better ones. P4 is essentially equal to Abec 7. P4 are used on probably 90 plus percent of machine applications.

IceCzar · Tuesday at 6:26 PM

personally I'm just happy its winter and achieving the 140F to 165F temperature differential is a lot easier if you can bury the spindle in a snowbank over night. Don't take the bearing over 260F

jim rozen · Tuesday at 8:04 PM

"Original inside and outside spacers on a B-port where not the same size."

The original bridgeport (M head version) had them the same. The bearings themselves were ground to fit that. Yep I have an original set and they are indeed 6205 radial bearings thus modified. I could mail them to you for inspection.

To the OP: enough already. Just go and do it, learn and have fun.

EmanuelGoldstein · Tuesday at 9:21 PM

mottrhed said:
Theres no such thing as perfect,

Even if there were, as soon as you put a 1" spindle (with an R8 taper ?) through them, then a load on that spindle; stress/strain where's your perfection now, sonny boy ?

To top it off, we're starting with a handmedown mill of unknown manufacture ... so yeah, let's spend 5,000 hours pulling on our weewees trying to evaluate the perfect bearing to magically turn a piece of trash into a Moore.

It's ridiculous, just like some crackpot comes in with yet another perpetual motion machine which he wants to discuss.

Richard King · 2023-01-18T03:51:52-0600

OT a bit. The last time I bought some larger (approx.4" OD angular contact class 9 bearings we could not find them in the states for a Besly double disk grinder. Our bearing supplier had to order them from Japan - NSK. The machines originally used oil bath for the lubrication and LL Lucas (the new machine rebuilder) told us to use Kluber (German grease) at 20% fill. I used my cone bearing heater to expand the inner race. I heated them to 120 F and they fell on.

Remanufactured Machines | J. L. Lucas Machinery Company, inc.

Tyrone Shoelaces · 2023-01-18T04:19:13-0600

Richard King said:
OT a bit. The last time I bought some larger (approx.4" OD angular contact class 9 bearings we could not find them in the states for a Besly double disk grinder. Our bearing supplier had to order them from Japan - NSK. The machines originally used oil bath for the lubrication and LL Lucas (the new machine rebuilder) told us to use Kluber (German grease) at 20% fill. I used my cone bearing heater to expand the inner race. I heated them to 120 F and they fell on.

Remanufactured Machines | J. L. Lucas Machinery Company, inc.

Did you mean 120 C or was it really 120 F Rich ? That doesn’t sound particularly hot for a bearing. I remember that the SKF induction heater I used was pre-set for 110 C. That was ample for most jobs.

Regards Tyrone.

Richard King · 2023-01-18T05:39:11-0600

I used to go to the SKF site to find the temp...sucks getting old.. I must have been 220 and not 120. Thanks Tyrone for catching that.

I just looked and SKF says 110 C or 230 F...

.

skf bearing heater manual - Bing video

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skf bearing heater manual - Search Videos

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Proper bearings for a mill spindle rebuild?

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