[landm]

Hello,

Bought a used Doosan DHP4000 horizontal a couple of years ago, used, 2007 model.

All along the finish has not been too good, a little wavy, not too bad but not what it should be. You can tell sombody has been into the spindle, the drive dogs have engraved markings on them.
There is .0002 runout in the taper. Sounds good though. 14,000 rpm, 40 hp and it is the big bearing type. Real clean machine.
Spindle rebuild= $16K new spindle= $39K

I have heard some horror stories in the past about the rebuilds and even some on the new ones, any advice?

[underthetire]

If its just a taper problem, why not have it re ground in place. And some rebuilders are not very good, some I've never had issues with.

[dcoupar]

If its just a taper problem, why not have it re ground in place. And some rebuilders are not very good, some I've never had issues with.

I agree with underthetire. If it's just runout and finish, your local dealer should have the equipment to regrind the taper in place. A whole lot less expensive than pulling the spindle, shipping it, having it rebuilt, and reinstalling it.

[landm]

Thank you! I do not think a .0002 runout is going to influence finish, it is a pretty light fethering in both x and y, both with low rpm and high rpm, 3 and 4 flute tools, high and low feedrates 3/8. 1/2, 3/4 carbide endmills (Niagra), . The inside of the spindle taper looks good.
It has been consistant since I bought the machine, perhaps I am missing something, let me know but I am thinking a bad bearing set in the spindle.

LandM

[underthetire]

How do the facemill finishes look? A loose bearing usually shows up in a sort of ripple look.

[landm]

We do not use face mills but wiht a 3/4" carbide endmill the finish is nothing to write home about. I took some pictures this morning but they did not turn out too good, I will try again later.
Thank all of you for your input!

[landm]

O.K. it has been a while but I think the pictures should be attached, let me know what you thing of the finish, I am thinking bearings.

[underthetire]

Pretty tough to tell I'm afraid. Find out from doosan the specs for push out on the spindle. Remove the tool, put a mag base with indicator on the face of the spindle and hit tool unclamp. I would expect some movement on a 14k spindle, but I don't know doosans specs what is allowable. Your finish almost looks like a spindle/tool out of balance issue.

[landm]

OK, I put a dial on the empty spindle and hit tool unclamp, got .00005", did ot about 10 times, no change. Called Protec and they said that is fine. So dose this mean my bearings are good?
I still need to check the push out on the tool to make sure my my shims are not too high and not allowing the draw bar to lock tool tightly but I think that is not likely.
On sugestion was that the finish looks like a ballence issue, the taper has a .0002 runout, it had that when I recieved it and it has not changed, is .0002 runout enough to cause a finish problem?
Thanks for helping out!

[underthetire]

The push out amount indicates bearings are fine. Run out and balance are 2 different things. The spindle itself may be out of balance, especially if it had been "worked on". Only a dynamic balancer will tell.

[landm]

Dynamic balencer, meaning putting the spindle on centers? Can it be balenced if an error is found or is that the time for a new spindle?

Mike

[landm]

O.K. the tool is ejected .022" , i will check with doosan next week.

So no tool in spindle pushout is .00005

spindle runout is .0002

finish is not too good, any suggestions?

[underthetire]

Most good service companies have a portable balancer. A sensor on both ends of the spindle, and a sensor to detect position. Not hard to do.

[landm]

Think we are going Pope on the spindle.

[underthetire]

Good luck with pope.....