BF20 Spindle nut wrench

[mzt]

Adjusting the preaload using the angle grinder wrench I had modified in haste when need arose, and then welded in

haste when it lost one of its pins was never handy.

Next time, I know there will soon be a next time, I will try the tubular one.





The strip of metal with a paper tape handle is a tool You will definitely need when re inserting the spindle

sleeve into the mill head.




Marcello

[Brass_Machine]

Hi Marcello...

Did you make the tubular one? How does it work?

Eric

[mzt]

Hi Eric,

I've made the short knurled wrench shown at the right in the first picture in the previous post: it is bored to accept the spindle, with two
portions of M4 screws acting as pins to engage the holes into the tightening rings. I've not yet used it, if not on the external
ring.

Some words and pictures to help focusing the problem, there may be a better solution for it.


The first picture shows the spindle, its sleeve and the upper (A, going to D) and lower (B going to C) ring nuts. The upper ring nut has two tapped holes
for M6 SH tightening screws (they should act on the slots and expand the nut).





The second picture shows the complete spindle (put a bit of grease on it) with the ring nuts already inserted: as You can (barely) see, there's no way to reach the upper
ring if not by fitting a screwdriver into one of the holes and hoping for the best (the ring will go a good deal down the sleeve, before
engaging the upper bearing). That's what I did, then locked it into position trusting the lower one to do the job.
It did, and does, for a while: then I start getting play and chatter (the lower nut still tight), open the mill and find the upper one running loose.
Plans for the next time it happens are about sliding my homade key onto the spindle to set the upper nut well tight first, then lock it and use that
same key to tighten the lower nut.





The portion of water pipe I had cut and used with the purpose of pushing the upper bearing into contact with its taper, so it went into
the mill toolbox, where I will find it again at need.


Marcello

[mzt]

Hi all,


Well, talking about 'better solutions' that tubular key would never work when tightening the upper nut: not unless I cut two slots to accept the locking scres heads.

On a different problem, will be clearer when looking at the next picture, there's a slot on side of the spindle sleeve: that sleeve is to accept a square key,
where the locking mechanism (a knobbed screw) will act. Needless to say, anytime You lock the spindle (reads, anytime You're using the mill as a mill) You're pushing the spingle out of its axis.
And You can actually see it, no need to take measurements.   



Two ideas: 

a) a quick and dirty one: drilling and tapping a hole into the mill head, opposite to the locking screw, for a brass pointed reaction screw.

b) (close) fitting a slotted collar to the spindle sleeve, fastened to the mill head. A screw, acting on the slot should grab it concentrically and more firmly than that locking screw.
   That would solve another problem, too.


Marcello

[mzt]

Hi everybody,

got a question about my fights with the mill spindle:

I have a problem with the spindle, its stariting to give a funny rattling noise, and need to take out the spindle but cannot figure out how to do it.
I found from your photo that yours have a same additional parts on the very end of the spindle which has four small magnets to send signal to the
tachometer and that parts is not on the parts list that I have.
Would be glad if you could tell me how you took off this parts.
I think if I can take this guy off, I can take out the C ring and remove the entire quill/spindle.

"Big Pipe Wrench" is the answer, and it is not an answer I'm proud of.
That part is not so hard to remove, when You know how it is held in place obly by light interference fit. IIRC, on subsequent works I levered it out using a couple of screwdrivers.


Make sure You have all the tools You need to put the parts back in place before engaging into the dismounting,
- a long hex key for the two M6 SH screws on the upper ring nut [(A), three pictures above]
- a c-spanner for the lower ring nut [(B), same picture]
- something You can use to tighten [(B)], a piece of pipe of the proper diameter with two notches cut to engage the screw heads should do.
- a rubber mallet to hit the spidle (it will come out from the bottom of the head)
- a plank of wood to protect the table (do not ask...)

A few more pictures showing the parts.









HTH
Marcello

[Jonny]

a) a quick and dirty one: drilling and tapping a hole into the mill head, opposite to the locking screw, for a brass pointed reaction screw.

b) (close) fitting a slotted collar to the spindle sleeve, fastened to the mill head. A screw, acting on the slot should grab it concentrically and more firmly than that locking screw.

a   I wouldn't be doing that, the spindle will rotate in that slot.
b  Need to make up a screw and turn away so its a very good fit in the slot. Now you will see what Chinese machines are like.


Proper tools to do the job one thing but if only doing once as a one off why bother making those tools. Screwdriver will have done the job or even a drill in the two holes, they don't need to be tight.

Having said that have to make those types of tools up so they don't mark finished product used weekly.

Might be confusing others when you say spindle moves with above screw. Check the tolerance in the quill, its Chinese, mines worn badly putting the lock on get around 1.3mm side and backwards movement towards where the rack and pinion is., poor design.