Thread: mt3 problem

Thanks Ueee,

I think you may be right Rob as the other MT3 tools do sit well in the quill, but it is hard to know the best way to go as I would
rather make a new arbor than a new quill. I will check the quill tomorrow ,I have a loos MT3 and will try and get an accurate measument
on the proper dept of the quill , Ueee's I dear looks alright but I would hate to butcher the tool as it would take a lot of the thread away and might scoch it all up,so I will be at it tomorrow, thank you both.

Nearly missed you then Phil well the CTC mob don't think it is a rogue ,and they don't make the separate type either,they said that's what they make.
so I would have to go else where,would make it expensive ,,for the old fellow.

Hi TKO,

Sounds like the CTC boring bar is just not compatible with your quill. Rather than modify either, what about getting an MT3 extension sleeve?

Here's the first one I found on ebay... you might do better with a more thorough search.
MORSE TAPER EXTENSION SLEEVE 3MT - 3MT FOR LATHE ETC FROM CHRONOS | eBay


Regards
Ray

PS I Just noticed you are in Shepp... that's where I am.

But Ray, one end of the extension sleeve might not fit.

TKO
Whats the largest dia of the taper at "to small" in your picture
https://www.woodworkforums.com/f65/mt...4/#post1629860

It should be bigger than 0.938"
If its not thats the problem. and a fix like Ewan/RC might be the go?
It it is bigger your quill is the problem. and maybe turning the end off it would be the go?
At least, thats the way I am reading the one taper dim chart I have checked.
Machine Tool Shanks (Tapers)

Stuart

Boring heads are made first and foremost to fit a mill. And low cost boring heads are probably aimed at hobbymills, that usually are limited by distance between table and quill. Hence it makes sense to keep the MT arbor as short as possible.

Facing off the tailstock barrel is IMO a bad idea; I would not want to modify a good machine tool, just to make it accept one particular make of tool. Especially not if it was a low cost tool. If that boring head arbor is halfway soft, I would try to face its shoulder off. If its hard, I would make a new arbor. That is fairly easy even if you do not own a taper attachment, as MT3 blanks can be bought cheaply. Another idea: the arbor of that boring head is threaded, so you can be swapped for a parallel shank arbor or an R8 or an int-type arbor. It may be possible to buy another arbor for it? I have a similar cheap India made boring head that came new in a box with 3 different arbors. You could even consider getting an MT2 arbor for it, and use a sleeve to make it MT3. Chris

Originally Posted by TKO

Thanks Ueee,

I think you may be right Rob as the other MT3 tools do sit well in the quill, but it is hard to know the best way to go as I would
rather make a new arbor than a new quill. I will check the quill tomorrow ,.

I wouldn't face off the quill, but it would explain why the morse is loose and comes right up against the back of the fitting.

Machining off the rear of the fitting should fix it, although you may then have to take a bit off the threaded section if it bottoms out at that end as a result of being inserted further.

Rob

I should add if the taper on the boring bar is less than 0.938"* you maybe able to have another go at getting CTC to exchange it.

Originally Posted by cba_melbourne

Facing off the tailstock barrel is IMO a bad idea; I would not want to modify a good machine tool,

But one could argue if the hole in the end of the quill is larger than .938"*.......then it isnt a good machine tool regardless of the brand name on it ....... Maybe someone reground the taper and didnt face the end? (I dont recall what lathe TKO has.) Then again I'm not to sure about the idea of using a boring head in a tailstock**, but assume TKO knows what needs to be done. If the error is in the quill this problem may reappear with any new MT3.

Having said all that, personally might be tempted to mod the boring head, but I would like to know where the error lay. Next time the mismatch may not be as obvious.


One other idea, some people like the idea of having a piece of paper around the taper. That might be enough to give you a short term fix if nothing else.

Stuart

*Unless someone else can find another size for an MT3?
**unless its for turning tapers.

The problem solved Rob was right after checking the quill was over size at the entrance,as there was 3/16 of an inch to the measure area ,after my calculations I decided to remove 1/16thfrom the quill cleaned end up every thing now fits proper ,made a small end peice to fit ,and I am a happy chappy,,now I know that is against the grain for most of you ,to remove the qill end but it has been that way for a long time no doubt ,I would like to thank you all including RayG ,stuart, CBA,for their comments, as well I have managed to get a photo of the finished job with the extension piece.








Also I was not right in thinking that removing the back part of the boring head would weaken the thread don't know where my head was at the time.

Looks good to me.

I think you did the right thing with the quill, as it was only a small amount taken off.

Cheers

Rob

Thanh's Rob ,I don't feel so guilty now,managed to find a pic of the 11 buk lathe I have

Eddie
005.jpg

It's not actually going to make any difference to the quill travel, as the effective morse taper is still in the same position.

Lathe looks good.

Got that Taiwanese style about it

Cheers

Rob

Good to see you have it sorted

I checked my TS taper this morning, and the big end measures .930", 8 thou under the gauge line size. I guess it just depends on the lathe and whether or not the taper has been re-ground at some stage.

You are right Rob it was really surplus any way.it is a Taiwanese lathe ,had it for 20 odd years and still in very good condition,does not get to much work now,I did make a alteration a long time back, to change the belt over you had to lift the cover and it was a nuisance
there was always tools to shift ,so I altered it and removed the part's that lifted the lid and fixed a handle out side that you can see behind the chuck that would activate the same as what the lid would do, would have been the best thing I have done to the lathe,had to fix two rollers to the back of the head stock to take up the slack so that I could change tools without having to turn of the motor or lift the lid.


Hi there Ueee,the lathe tail stock has never been ground,the chuck has been trued up once some years back, other than that it is still in very good condition,I had the boring bar as a present ,mostly I used the cross slide for that type of work,and i was disappointed when it would not fit the tail stock many thanks for your input,.

Eddie