[markbanman17]

Greetings,

I recently tore apart my spindle on a mill I got, It had been sitting sometime. Its a Milltronics Partner 1D (The bearings had rusted inside an Im doing a Yaskawa Retrofit)I have not rebuilt a spindle before and budget does not allow for me to out source. I have got talked to Milltronics and managed to get the bearings specs I need, Ordered NSK bearings. Im aware how to grease the bearings. Dont need to touch on that. What I am looking for advice on is how to get the shaft back into the cartridge without hurting the bearings and making sure that the spindle doesn't turn into a noisy heater after. Currently Cartridge is still in the Z axis. I was able to pop everything apart. I thought if I leave the cartridge in the Z axis I have the "hydraulic press" I need if I introduce a bottle jack on the table.(I dont have a press, but need be I can get access) I have a lathe I can make anything I need to for pressing the bearings on correct shoulders and such. Its 2 flush angular contact bearings on bottom with a nut holding them down and 1 deep grove ball bearing on top (no fastener). KEEP IN MIND!!!: This is not a 40hr a week machine. This thing may run a couple hours a week and no big production line is waiting on it. If the spindle would last 2 years at that duty cycle Id be pumped. By then I would be able to justify a professional rebuild. If I knew the mechanical steps to do this Id be more confident.

What can I do to ensure the bearings go in well?
Should I be looking into the Drawbar Spring Washer condition before reassembly?
Is it dumb not to get taper reground?
Was it dumb for me to try this?
What else am I not thinking of?

Edit:
should I press A/C bearings onto shaft, press ball bearing into cartridge, put shaft and A/C assemnly into freezer then try to pressing shaft into cartridge?
do I need to support inner race of the upper ball bearing while pressing shaft through if I follow above method?
Is cooling shaft a bad idea due to condensation?


Any and all help greatly appreciated.
Thanks

[sportybob]

Hi Mark,1st off, if you never have rebuilt a spindle you need to be clean, clean, clean. get some freezer / butcher paper at the grocery store and use it to assembly. If any dirt shows up it will be seen. most people will have a tendency to over grease the bearings and use the wrong type of grease. I use Kluber isoflex NBU-15 or LDS-18 ( https://cnc-specialty-store.com/grea...5-50-gram-tube.) at a 35% fill rate per bearing. I use a 20cc veterinary syringe to get in between the balls, about 1/3rd the way on one side flip the bearing and 1/3" on the other side. Then rotate the bearings to spread the grease. (too much grease is almost as bad as too little grease)


Before greasing, put the two lower bearings together in the correct direction, measure the inner and outer heights. then measure the inner and outer heights of the spacers. you should have about .0005" preload. grinding of the spacers is sometimes needed.

Remove the drawbar from the shaft.Bearings can be pressed on the shaft OK, (I use a bearing heater) They should press on with little resistance, if you are getting harder resistance then you hit a burr or the bearing is cocked.

Pull the cartridge from the machine so that it and the shaft can be cleaned. You have a lathe so chuck it up and let it do the work. some degreaser and some light scotch bright should clean it up. For rusty areas try using " Rust-Mort" with light scotch bright, (Great stuff, goes a long way with a spray bottle, good for rust prevention, cleaning up tables, tools etc as well, ) final clean with non chlorinated brake cleaner,
Assemble the spindle on the paper, The shaft should slide into the cartridge with little effort.
It is a good time to replace the drawbar washers. (I have a kit, $135.00)

For the spindle taper you would have to look at the condition and determine if it need to be reground. use an indicator to check run out. as long as you have about 70% tool to taper contact you should be good for this machine. use some prussin blue / red to check the contact.


That the quick and dirty of it.
The P1 D spindle is a good learning point with only 1 pair of angular contact bearings. newer machines use a matched duplex pair and a matched triplex set, with 5 bearings it gets a little trickier

.

when reinstalling the spindle into the machine, set it up on a 4 X 4 or ?? and use the handwheel mode to Z down, once you get a couple screws into the cartridge you can Z up for better access.

Mark you have my # if you have any questions.

sportybob

[markbanman17]

Hey bob, thanks! That's a load of valuable information. Okay greasing the spindle I feel pretty good about, bearings will be here in a couple days and I will check the preload you talked about.

The cartridge, originally I tried removing it from the z axis and couldnt get it to budge, that's partly why it's still in there, should I put the z axis on blocks and hit a little harder? Or any other tricks? I'll be making a homemade bearing heater I'm thinking to get the bearings on, need to research that a bit.

Is it possible for me to do the spring washers after rebuild if I have to? There all intact so I may try it to save a few bucks at this point till I know I did everything else right.

I'll be ordering some of the blue to try out the taper, can I correct that with a stone if it's just a high spot or 2?

I've done almost nothing yet on the spindle but disassemble completely, later this week or weekend I'll start cleaning the shaft and cartridge on yhe lathe if I can get the cartridge outta there,

Say the taper needs to be reground is it okay for me to have finished the spindle rebuild before doing this?

Thanks!

[yugami]

What did the bearings run you if you don't mind me asking?

[sportybob]

Hi Yugami, the bearing prices run all over the place. depending on where and how much product you buy from a supplier. duplex ( matched pairs) run about 1.5% over the cost of single bearings, Triplex ( (3 matched bearings ) can run 2 X the price of a duplex ( pair).

IMHO, you should always check with me before buying. I don't up my prices very much. And will usually beat the pants off other suppliers. Why? because I am here for the small guy's. And I buy more then you. and, have spent almost 10 years finding the right suppliers. Oh, it's true.


sportybob

[sportybob]

Hi Mark, The cartridge is held in with 6 bolts on the bottom side. double check all 6 are removed. the cartridge usually slides right out. Try blocking up the head behind the cartridge, putting a block of wood under the cartridge with about 1/4" gap ( to "catch" the cartridge when it breaks loose) another block on top of the cartridge to beat on. Try spraying some PB Blaster down around the outside of the cartridge and around the mounting flange.


stoning high spots on the taper is OK. Usually I have the tapers ground with the spindle in the machine. This runs about $600 around here. You would need to call around. If you find a place to grind it, If they can do it "inhouse" I would think that it should be done before you mount new bearings.

sportybob

[markbanman17]

Hey Bob, Ive been soaking and beating and slowly getting it to move, thats the one place that got rusted on the machine while in storage, spindle bearings got rusted to... One thing im wondering that I cant find a solid answer on is the temp of what im allowed to heat spindle bearings to. Is that a manufacturer spec? or can the Isoflex 15 on get so hot? a general rule of thumb? My plan is a thermal couple monitered toaster oven while my wife isnt looking... certain bearings have plastic type ball retainers also.. pose a risk?

Thanks

[sportybob]

Hi Mark, usually heating to about 160 F is OK all around. Hard to control the temp with out a bearing heater designed for that purpose. I suggest you press them in. remember to use the inner race to press on.

sportybob

[yugami]

Any tips on spindle removal? I need to look at my washers and bearings. Having some issues with edge finish having a lot of fine scallops and the spindle feels pretty hot after running for a while.

I took the 6 screws out and a little pressure with the tool changer arm popped it out but its hung up and I don't want to just start prying.

Might be giving you a call bob.

[sportybob]

HI yugami, Yes give me a call.

Not sure how you got to, removing 6 screws and a tool change and hung up. Tool change should never have been involved.

The drawbar washers can be changed with out removing the spindle. Checking bearings requires removing the spindle / cartridge assy.

Give me a call
952-288-6340

sportybob

[yugami]

I meant the pnumatic part of the drawbar

[sportybob]

Hi Mark, How is your spindle project going?

sportybob