Stuck Morse Taper - new to this!

[JonnyB]

I’m new to this forum and fairly new to milling having just bought my first one recently. It’s a new 350W Mini Mill by Osaki, I guess it’s just a rebrand of the Chinese made model, and exactly the same as the Clarke CMD300. It’s new and unused with all the original ear wax still on it but I bought it off someone on eBay. Looked all fine but now I have started to try to use it, I’ve noticed the Morse taper attachment is really stuck in the female shank (or whatever you call it). I’ve tried getting it out the normal way - releasing the draw bar and give it a hit (I actually damaged a couple threads doing that so have learned not to do that but put a 10mm steel rod and hit that instead). No luck. I’ve tried heating the female part of the Morse taper with a micro butane torch and tried hitting it again - still no luck (although I don’t think I managed to get it that hot, so have ordered a proper propane torch). Now I’m wondering if I am missing anything (a locked thread or something I should know about), or where I will need to dismantle the drive and attempt to dismantle with a hydraulic press or something?!
Any ideas? I tried to cold spray (with an upside down air duster can) the drill taper but it had already hot from conducting a lot of heat from the butane torch and the condensed gas was just vaporizing on contact without managing to cool it down at all.

I’m guessing I need to put a lot more heat into the female shank because it probably barely 100 deg C or so, but it makes sense that I heat the outer and cool the inner parts but they are contacted very well so seems tricky to do.

Has this happened to you before? Any tricks you can recommend? Better to torch and hammer or dismantle and press it out?

Thanks for the help

[Dr Stan]

First I highly recommend working on your posting so your text is not so huge.

I'm not familiar with this model, but usually there is a cross slot in which one can insert a drill drift to remove a stuck MT sleeve, etc.  Please post a pic of the spindle so we can get a better idea of the problem.

[rleete]

You just locked it up too tight. Hit it with a larger hammer.

[f350ca]

I'd be very careful heating a spindle, the bearings won't like it.

[JonnyB]

Oh wow, just opened this on a computer; the text is huge! I copied from text app on my phone (as my phone kept refreshing and losing my text) - anyway...

Here are some photos. I loosened the lock nut with a c-spanner but don't think that actually has anything to do with changing the taper attachment, so have tried hammering with the nut loose and also tightened.






I might need to buy a mallet for that (I assume steel for impact, not rubber).
Not sure how to drift it out. Doesn't seem to be any points to drift from.

[rleete]

Remove the inner bushing - the black ring that is where you put in the drawbar - and put in the largest piece of steel rod you can fit inside the taper. Hit it with a hammer. It will pop out, you just have to hit it harder than you think you should, as it is jammed up in there.

I have the same mill. It is common for inexperienced users to way overtighten the drawbar and get the tapers locked up.

[EdK]

(04-16-2019, 01:30 PM)JonnyB Wrote: Oh wow, just opened this on a computer; the text is huge! I copied from text app on my phone

No worries, I fixed it for you.

[Highpower]

Just a suggestion. You might want to start looking for a new drawbar and drill chuck arbor now rather than later. My spidey senses are telling me the threads on both pieces are just waiting to cross-thread and/or seize together soon.

[JonnyB]

Thanks for the resize.

Great suggestion... One 4lb hammer and a 1/2" wrench extension bar later (and as you suggested, removed the bushing to fit the bigger bar in), it worked!  I moved the mill from my flimsy wooden bench to the concrete floor and lowered the z axis to minimise the force on the vertical pillar. did require a bit of a whack, and my 1lb hammer wasn't up to the job. I re-cut the thread on the draw bar, looks a bit beaten up but at least it threads again fine.

Thanks for the help. Now to see if my cheap chinese ER32 chuck has been made properly (I've heard they can be hit and miss in terms of quality control!).

[Hawkeye]

For future reference, on those mini-mills, loosen the drawbar just enough to leave about a 1/8" gap under the nut. If you only have a few threads engaged, they will be stripped very early in your career. When mine stripped out, I used a grade 8 bolt of the appropriate length as a replacement, with a T-washer to support it at the top end. I keep a brass hammer handy to whack it out after the slight loosening. (keeps the nut from getting mushed out) The replacement has held up for quite a few years.