[Arich0908]

I believe after I do my belt set up ill be well over 15,000rpm with X1.
My motors max is 2.5 hp @ 7200 rpm.
then there is the 3 step pulley it has to go through.
I dont think my bearings were intend to go any where near that.
I was going to get full ceramic bearings just cause they look like there the best .
But I really don't know enough bout them to justifie getting a set of hybrid stainless or ceramic bearings.
Can some of you help me . What should I grab and why? Or will I be all rite with the stockers?
Will I really see any type of difference spending 100$ on a set of bearings?
I know I ask allot of ?s here thanks for the help,
Anthony

On a side note do any of you who have a sx1 or x2 use the tilt head function?
Im bout to buy the new base and Im wondering if I should buy it with tilt or without. Ive read some people say they never even use it . It just gets in the way and its a bother having to tram it all the time.

[photomankc]

I could see it being useful at times but the machine sacrifices a lot for that feature. I far prefer the tilting head to a tilting column. If I were sticking with my X2 a column brace would be high on my list to install. Lots of other ways to drill/mill the occasional angled hole/slot.

[wildwestpat]

Take a look at the bearing manufacturers data and a price list from one of the large stockists of bearings for industry.

The bearings in your standard mill spindle is probably 35x72x17mm. As a generic bearing the uper speed linit is going to be well under 10,000 rpm before any deratings for load both radial and axial. This is why the standard machine has a maximum speed of arround 3,000 rpm.

Yes changing the bearings to a better class will improve things but at a price. For example a SKF hybrid bearing no 62072RZTN9HCTC3WT (a hybrid ceramic stainless steel bearing) will cost between three and four times the cost of the X1 mill. For that you will get two bearings with a speed rating of 18,000 rpm. The speed should then be derated to take account of the dynamic conditions due to both imbalance in the rotating assembly as well as cutting edge loads and any pre-load necessary to locate the shaft. These are deep row type so they will support some axial loads but not as much as angular contact syle bearings. Angular contact bearings of this size are rare beasts but again look at the full data sheets as the increase in axial load capability is not that much better considering the cost differential!

If you do the sums you will find that to get your desired speed of 15,000 rpm plus you are going to have to fork out some very serious cash or reduce the diameter of the spindle and bearings as others have done. This is why the spindles for high speed operation usually have multiple bearings with a small diameter shaft. The out of balance forces need to be controled by both dynamic balancing and some cunning arrangement to power the shaft to avoid introducing rsonances or excessive side loads. The use of direct drive where the motor and the tooling shaft share a common spindle avoids the side load of a belt or gear drive but still involves careful banancing if satisfactory bearing life is to be obtained.

Have you worked out the feed rates and speed you require for the type of work you will be doing? Unless you are engraving or grinding hard materials with very small tips then you may find there are other solutions such end mills with multiple flutes.

Hope this helps crystalise your dreams before you hand over wads of cash. Regards Pat

[Arich0908]

I would like to do engraving at some point do I as of now no.
I do youse plenty of smaller end mills for my hobby . 3/16 1/8.......
I understand what your saying cost of bearing vs cost of mill but then again I spent more in tooling than I did on the mill. If im going to do something ill do it correct.

I think Im going to pass on the column tilt and just get the y extension.

[Teyber12]

what pat is saying is you should be doing feed/speed calculations for what you are doing and get what RPM's you want from that. For engraving it would be much simpler to have a engraving attatchment off the side of the x1. but you won't be doing any real engraving until you have a cnc mill. 15k is huge. I did a conversion on my x3 to take it to 6k rpm's and my stock bearings got destroyed after maybe 20 hours of use. im going to be looking at $200+ in new bearings probably more just to run at 6k. I would consider bumping up the rpm's from stock to something more in the 5k range.

Just trying to save you a headache.

cheers

[philbur]

Unfortunately putting 15,000 rpm bearings in a 3,000 rpm spindle doesn't give you a 15,000 rpm spindle. There are many factors that need to be taken care of. The easy bit is buying the bearings.

Phil

I would like to do engraving at some point do I as of now no.
I do youse plenty of smaller end mills for my hobby . 3/16 1/8.......
I understand what your saying cost of bearing vs cost of mill but then again I spent more in tooling than I did on the mill. If im going to do something ill do it correct.

I think Im going to pass on the column tilt and just get the y extension.

[Arich0908]

Unfortunately putting 15,000 rpm bearings in a 3,000 rpm spindle doesn't give you a 15,000 rpm spindle. There are many factors that need to be taken care of. The easy bit is buying the bearings.

Phil

Please explain further im all ears . This is my first mill my first build up . So I am very naive .

[TXFred]

I think you're asking for way too much from that little X1.

I did some engraving at work yesterday. The machine was a Haas TM-3 with a 7.5 horsepower motor. Sticker price is $33,000.00. But the spindle only goes to 4000 RPM.

It did the job just fine.

To get a spindle anywhere close to 15,000 rpm from Haas, we'd have to get the VF-2SSYT, which has a 12,000 RPM spindle. This machine sells for $65,000.00

So what you're plotting here is to add a $32,000.00 feature onto a $200 machine.

Without knowing what you plan to do with the machine, I cannot be certain. But it looks to me like you're about to spend a lot of money on your X1 for absolutely no benefit. Just get the machine to run 4 or 5k and you'll be fine.

Frederic

[vlmarshall]

Most of the engraving I do is with 60-degree single-flute carbide engraving tools, and even in a Haas with a 10k spindle I only run them at 5000RPM or so.


Speaking of Haas machines, I work in a shop with 8 of 'em...and only one has a 10k spindle, the rest are 7500rpm. I use the 10k machine for about 16 hours a day milling 3d contours at 300 IPM speeds... I haven't seen an X1 do that yet.

[Arich0908]

It runs stock 4k.
Wheres the fun in that?Im not willing to spend thousands of dollars but if I see nice improvements i dont mind spending money but I totaly get what every one is saying.
I have no need to buy a better mill so far im happy with my "Little X1"

You guys are reading into this way to much . I have a mill as a hobby . I dont do this daily .
I asked a simple question. .
I know what mill I have , Its bottom of the line Im very aware . I know how much it cost I bought it.
Soooooo
I asked bout ceramic bearing and were comparing 30k mills to my X1.

[vlmarshall]

I know what you're saying; I use a little SHERLINE at home, after all... and love the thing. It runs just like a scaled-down version of the big stuff.

Actually, there's an option for ya, the Sherline spindle will run 10k with a pulley swap, and is available in many configurations for bolt-on use, for about $400. I've bought one to use on a CNC router.

http://www.sherlinedirect.com/index....category_ID=32

[wildwestpat]

Hi Arich0908

Don't take the comments the wrong way the intention is to save you wasting money as well as time. Ceramic hybrid and all ceramic bearings are specialist items and require close tolerance mountings as well as being very expensive. Yes you might get some surplus or unmarked bearings on ebay or as unbranded from a stockist but do not expect to achieve long life at high speeds.

Suggest you look at the Machinists G-Wizard by Bod Warfield http://www.cnccookbook.com/GWizard/G...nstall1SC.html

Bob has done a geat job in pulling together the parameters that impact on the common turning and milling operations. Play with the speed and feeds to get a feel of the interaction between spindle speed and feed rates. You will then see why more spindle speed is not the only solution to excitingly fast machining rates.

What ever you decide to do have fun and above all stay safe. - Regards Pat

[sansbury]

It all depends on whether your goal is to make machines or use machines to make things. Time spent making the mill is time not spent making parts. If your goal is to make things, buy a Dremel or Proxxon rotary tool and attach it with a pipe clamp. There's your 35K spindle!

[Arich0908]

I dont want a spindle that goes 35K . I never said that.
All I want to do is upgrade my bearings to meet or exceed the new motor and pulley system Im installing on my mill.

Thanks Pat,
I believe at some point in time we all waste money . It just matters in whos eyes its a waste. To some people buying a mill is just pointless and a waste. It all depends on who the buyer is.

[sansbury]

I used to have an X1, now an X2, both CNC converted. My opinion, leave the stock bearings in and keep your speeds down under 4-5K. That will work OK with smaller cutters and shouldn't give you much trouble. Otherwise I'd get a spindle assembly from Taig or Sherline which are made to go to 10K and cost ~$150. The Taig spindle has a built in ER-16 collet holder which is perfect for small tools.

Disassembling and re-mounting new bearings will quickly turn into an all-weekend project pretty easily. With the way these $300 machines are made, there's no guarantee new bearings will even do any good. If the spindle is misaligned by .0001" or so it might be fine until you get to 5-6K, beyond that, the bearings won't fix the problem.

If all you want to do is engrave with a small V-bit, the best solution is to mount a rotary tool like a Proxxon. You will see people doing that on $30K mills in professional shops because it works really well.

[serriadh]

I dont want a spindle that goes 35K . I never said that.
All I want to do is upgrade my bearings to meet or exceed the new motor and pulley system Im installing on my mill.

It would perhaps be better to spec your belt drive to suit your bearings! I've spent a long time going through the various spindle threads in this forum, and the common factor is that high speed spindles are hard to make even if you're a pretty talented machinist. Forgive me if I'm being presumptuous here, but I'm guessing you're just starting out too!

So, my quick summary, which may well be innaccurate or incomplete! Low tolerance bearings will result in a lot of runout, which is going to wear out larger tools quicker and risks breaking very small bits. High tolerance bearings are very expensive, and if you mount them in a low-tolerance housing they'll wear out quickly and leave you with an expensive repair job.

If your spindle or tooling is not well balanced, it will impart vibration and radial loads to your bearings which will also wear them out quicker. I seem to recall reading that when you're running at 10krpm or higher you have to start worrying about this problem.

Your next problem is power... if you're running a low power motor at high RPMs you're not going to get a whole lot of torque at the tool which is going to limit how big a tool you can use or how fast you can feed. If you don't feed fast enough, you'll wear your tools out sooner. As I think someone already said, you should see about getting a copy of G-Wizard from Bob Warfield's site at look at the performance requirements for the sort of machining you'd like to use.

Lastly, if you look at some of the other threads where people have upgraded the bearings on their import mills or kept the stock bearings and just sped the thing up anyway, they've ended up under 7-8krpm. I'd follow their example, and get something achievable and practical done first. But that's just me ;-)

I believe at some point in time we all waste money . It just matters in whos eyes its a waste. To some people buying a mill is just pointless and a waste. It all depends on who the buyer is.

Frying expensive bearings is pretty much a waste of money from anyone's point of view, bar the education you get from learning from your mistakes.

For a couple of hundred bucks, I'd be getting a little sherline spindle and running that at 8-10krpm rather than trying to get an X1 spindle running that fast.

[philbur]

It's not that difficult to make a spindle that will run at 15,000 rpm. The trick is to make it sufficiently rigid for a milling spindle and at the same time get the bearings to survive a reasonable length of time. You may consider $5 deep groove bearings as consumable components, not many would consider $300 bearings in the same light. High-speed milling spindle bearings are incredibly precise components and they require an equal precise spindle housing and shaft etc, etc. In addition the bearing layout for a high-speed milling spindle, by necessity, needs to be more sophisticated than your average Chinese hobby mill spindle.

If you want to build a high-speed spindle for your mill you should start by studying spindle designs not bearing prices. Building it by trial and error can get very expensive.

Phil

Please explain further im all ears . This is my first mill my first build up . So I am very naive .