[damnifiknow1]

I have an NV5000 that keeps breaking the bolts that hold the spindle dawgs(ears). Every couple of months i have to replace the broken bolts. I have other moris doing the same process without any issue. Does anyone have any idea why it is doing this? Has anyone ever seen this happen?

[underthetire]

Yes, your drawbar is shot at minimum, possible taper problem as well.

[Kittiwat]

Hi,
the bolts that hold the spindle dawgs(ears)

Where is the bolts?
Sorry,I can not imaging.

On detection ring?

[damnifiknow1]

Thanks for the info. This machine does have a rebuilt spindle in it. I also had to replace some broken washers about a month ago due to low clamping pressure and noticed that it cracked the clamping fingers as well. But if it is a taper issue, Is that a replaceable part or is it built in to the spindle?

[motionman]

I have a company that I work with that can do an on machine regrind if the taper is damaged. email me if you need help with this [email protected]

[Kittiwat]

You meaning Compression Spring at Draw Bar set?

How to check clamp force?
Normally if BT40 standard tool clamp force 11000 - 16000 N

Where is the broken bolt?
Please indicate position to clear.
I think, if you modify the taper of spindle unit. It not good solution.
I do not recommend.

Attachment 252626

[underthetire]

I would assume you replaced all the o-rings, springs and retention fingers? How about the drawbar shaft? Those test to go bad on the NV5000's, with wear on the shaft not letting the washers move freely. There has been an updated version of the drawbar, however you would have to replace the entire thing. Also, what kind of grease was put on the drawbar during re assembly? Have you tested the clamp force? Should be ~2200 LBS.
And yes to the field re-grind if needed, might want to blue a good tool holder and see if anything is wrong with the taper.