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Black_Moons
01-01-2011, 12:17 AM
Hi, How does one align a quick change MT2 adapator to the spindle via the cross slide?
I would love to do some more of my 'smaller' low stress drilling with the carriage, since it feeds in/out so fast compaired to tailstock, its much easyer to peck drill with, But im kinda stumped on how to prevent a bell mouthed hole due to misalignment along the cross slide axis.

I guess its not 100% critical since I glue the inserts into the hole anyways, But it would be nice to get the hole as accurate as I can.

So how do you align it with your spindle along the cross slide axis? Within a mil or two idealy, And faster then it takes to drill with the tailstock..

boslab
01-01-2011, 12:29 AM
I just face off a bit of bar and align with the 'pip' with a centre in the holder, works for me for rough and ready drilling
regards
mark

Davo J
01-01-2011, 03:06 AM
You could put a MT2 dead centre in the tool holder and line it up with the pip as described above or another dead centre in the spindle and use the 6 inch ruler trick, like used for setting tool height.
Using the ruler between centres, you could get it near perfect both vertical and horizontally.

Dave

The Artful Bodger
01-01-2011, 03:15 AM
Yes but, how does one ensure the drill is parallel to the spindle axis before adjusting for height and cross slide position?

Davo J
01-01-2011, 03:41 AM
Just run the dial indicator along the side of the tool holder when setting it up.

Dave

huntinguy
01-01-2011, 03:43 AM
All I have ever done is dialed in the side of the holder. Seemed to work okay for me.

djc
01-01-2011, 04:08 AM
...How does one align a quick change MT2 adapator to the spindle via the cross slide?

Have a little search for posts by Tim Leech on his Dean, Smith & Grace lathe. They have this facility.

You have four degrees of freedom with the drill: it has to be both parallel and concentric with the spindle in both a horizontal and a vertical axis.

For this reason I wouldn't use a QC holder. Here's how I would proceed:

1/ Find a way to position and lock the cross slide to the saddle that is repeatable: as simple (brutal?) as a reamed hole through both and a taper pin. A latch or pin that drops or inserts between two stops is another way.

2/Fix a large lump of metal to the top of the cross slide such that the middle of it roughly coincides with the spindle axis. This must be fixed so that it can be removed and repositioned in a repeatable manner. Again, dowels or taper pins. If the material is aircraft billet, that's better.

3/With drill and then boring head in spindle, make a hole in the lump of metal.

4/Loctite/silver solder/press/shrink in a parallel-sided female MT2 sleeve.

With a little thought, if you position your lump towards the back of the cross-slide, it can serve dual purpose as a rear toolpost.

Ian B
01-01-2011, 05:39 AM
Here's a larger version of what DJC is describing:

http://www.gandmtools.co.uk/cat_leaf.php?id=295

This one clamps to dovetail profiles along the edges of the cross slide and has a 5MT socket.

The problem with using one of the quick change toolholder types is that the thrust when drilling will try to rotate the toolpost. not a problem if the toolpost is pinned to the topslide (mine has this feature), but it could be a problem if you're just relying on the friction of the central locking bolt.

Ian

Lew Hartswick
01-01-2011, 11:05 AM
That removes 3 of the 4 degrees of freedom leaving only the cross-
slide. should be a peice of cake.
...lew...

mike os
01-01-2011, 11:33 AM
couple of Q's

what do you actually gain doing it this way... other than better readout on the depth via the dials/dro?

given the pita of setting up accurately (over tailstock that is already alligned) is it really worth the effort?


I could see the point if CNC, but for manual use?

Ian B
01-01-2011, 11:44 AM
Lew,

If you mean the one in the pic I posted, I think there's an adjustable stop shown at the bottom right. I'd guess that a pin goes in the saddle and the whole unit is slid forward until the stop touches the pin. This would give a very fast way of aligning everything no matter where the cross slide is, and still allow it to be slid back well out of the way when not in use.

Mike, one thing you gain is the power feed option. handy for puting 2 1/2" drills through steel. The only thing that concerns me a bit is the assymetrical thrust - under normal machining, cutting forces press the saddle down onto the inverted vee ways. It looks to me as if drilling with this unit is going to cause the left hand end of the saddle to try to lift off the ways.

The one shown fits my lathe, but I'm not keen on handing 150 quid over for it just yet...


Ian

mike os
01-01-2011, 11:56 AM
OK I can see that... thought we were talking MT2 tho? seems a little small for a big bit?:D


My Dickson post has an mt2 holder with it...;)

Carld
01-01-2011, 12:02 PM
Then there's the fact that a drilled hole is seldom if ever the same size as the drill bit. Aligning the height of the QC tapered drill holder is the one thing that will stay constant after setting. When the drill holder is changed out for other operations and then needed again you will have to establish the alignment horizontally again.

I bought a tapered drill holder and the more I thought about it the more I realized it was easier to use the tailstock for drilling. Slide it up, use it and slide it back. Also, I began to wonder how the drilling force could turn the tool post and bugger up the work.

I decided if I wanted to do heavy drilling I would attach the tailstock to the carriage and use the power feed to move the tailstock along with a slight drag on the tailstock lock. That way I could lock the tailstock quill to take the some load off the quill key.

So far I haven't had the need to do any heavy drilling at home like I did at work. I do use a dead arm to hold the drill from turning on some jobs and that too takes the load off the quill key.

EDIT: To align the QC holder I put the flat face against the face of the 3 jaw and clamp the tool post down. Then I put a dial indicator in the 3 jaw and indicate the bore of the taper hole in the drill holder. I only did this once and saw it took to long to do it and the tailstock was faster.

RussZHC
01-01-2011, 12:25 PM
1/ Find a way to position and lock the cross slide to the saddle that is repeatable: as simple (brutal?) as a reamed hole through both and a taper pin. A latch or pin that drops or inserts between two stops is another way.

2/Fix a large lump of metal to the top of the cross slide such that the middle of it roughly coincides with the spindle axis. This must be fixed so that it can be removed and repositioned in a repeatable manner. Again, dowels or taper pins. If the material is aircraft billet, that's better.

3/With drill and then boring head in spindle, make a hole in the lump of metal.

4/Loctite/silver solder/press/shrink in a parallel-sided female MT2 sleeve.


How about taking that big lump and fastening it to the follower rest attachment points (isn't it usually a couple of bolts on the right hand side of the "saddle" (term?)...you may need a third hole say on top of the saddle to establish 3D security but...it would be starting in approximately the correct position vis a vis the spindle

BadDog
01-01-2011, 01:33 PM
Another problem (I didn't see mentioned) is that most cross slides lack a locking feature. Not an issue with normal lathe operations since slack is taken up and held by the cutting forces, not so with drilling. So short of adding one, or using positive location like the pin, getting it to stay exactly located (if required) is a problem.

I have a 3MT Aloris holder, and have found it to be of little use. As long as compound angle changes are not required for repeat parts (in itself not something I do very often), and the tool post has been dialed square (for instance, when parting off is part of the process), then it can be used somewhat effectively for non critical MT tapered tooling. For instance, reaming would work since perfect coaxial alignment is not critical (it follows the existing hole), consistent (calculated) feeds are handled by the apron drive, and you don't have to swap out tail stock tooling for that operation (or at least it removes one or more swaps). But for drilling, not really interested...

Black_Moons
01-01-2011, 03:02 PM
Eh, My idea was to use it because its just sooo faster to retract a drill to clear it of swaff and insert it back in, as opposed to using the tailstock handle. My acrylic blanks need a few withdrawls to keep the flutes clear

Astronowanabe
01-01-2011, 04:22 PM
I do not have one nor have ever used one but if I did I think what I would try first is:

chuck a bit of scrap in the headstock and center drill it with the tailstock

put a dead center in tailstock and another your holder
would want the DC in the holder to have a center divot in the small end
would want the DC in the tailstock to be able to reach that divot

loosen up the toolpost set the front of the DC in the holder in the hole you made in the scrap in the head stock
put the tailstock deadcenter in the divot in the back holder DC
tighten the tooholder down to lock horizontally then tighten the holder in the toolpost to lock vertically

the result should not be the carriage drilling not much dofferent than tailstock drilling as far as alignment goes ... in theory anyway :)

edited: to adjust the ordering of letters for those to whom such trifles matter

Black_Moons
01-01-2011, 05:10 PM
Hmmm, I just realised another method that might work. If you mount a center drill so the flutes are horzontal, You could just test drill and move it via crossfeed untill both flutes are making equal chips. (a few mils out, And one flute won't make ANY chips)

BadDog
01-01-2011, 06:41 PM
Eh, My idea was to use it because its just sooo faster to retract a drill to clear it of swaff and insert it back in, as opposed to using the tailstock handle. My acrylic blanks need a few withdrawls to keep the flutes clear
I just move the TS back and forth to clear deep holes. I recently had to make an order of 7 rollers from 6" x 12" long aluminum solid. Other than facing, the first operation was to drill a hole just over 1/2" dia (using a high helix extra long drill) all the way through, followed by a 1" drill from each end to meet, and finally an adjustable chucking reamer to running clearance for shaft. Talk about clearing chips! But I just set the saddle so the TS came up against it with the ram retracted and almost ready to start cutting. Drill until you need to clear, reverse one round to get the edges off the material, pop the TS lock and slide back to clear chips, slide back to saddle and relock, take up screw slack and begin again. My ram has just over 5" travel, so when I ran out, I cranked the ram back, moved the saddle just under 5" (DRO), and locked the saddle to begin again. I've also used a copper jawed clamp on the ways when the saddle wasn't convenient to use as a stop.

Also, for those talking about swinging a DTI (or other dial) around the lathe axis, depending on dial quality and accuracy needs, you should consider the affects of gravity on the dial. It can be somewhat surprising to see how much affect it can have on readings.

tmc_31
01-01-2011, 06:53 PM
How about chucking up a ground bar in the 3 or 4 jaw then running the drill bit up next it. Then you would align the drill so that it was parallel with the bar.

Tim

Black_Moons
01-01-2011, 07:02 PM
Hmm, Found another intresting solution.
14mm socket + cordless drill = Powerfeed for tailstock (tailstock uses two 14mm nuts to secure the handle)

Unfortualy my cordless drill does not quite go slow enough to be used as power in feed, and I got a drill bit stuck into one of my blanks! Got it out after enough fiddleing however..