Self ejecting drawbar M1

Looked at quite a few posts re designs for self ejecting drawbars but can't see how to get one to work with my Senior MI without work on the spindle. Thought of making some type of cage fitted to top cover of vertical head but looks very inelegant. Can loosen a Clarkson chuck with wedges between base and chuck but started to use straight M2 collets for drilling etc. and the only way to remove those is to strike the drawbar, can't be doing the bearings any good. Anyone come up with a solution in the past?

Graham W

'Tom's techniques' shows him with a pneumatic drill attached to the mill top with forward/reverse. I still don't see how that deals with disengaging a taper unless he's using a impact action on the undo. Whether that is more or less damaging to bearings......

Most of the industrial designs are for 30/40/50 or R8 tapers rather than Morse 2. From the video you can see that Tom's machine has an R8 collet, so loosening the drawbar is all that is required for the collet to simply drop out. The air driver does that for him.

With Morse you are stuck with wedges or hammers - or a cage to reverse the quill back up against. The bearings can't be that delicate surely. Give it a good belt. Use a plastic / leather hammer to reduce the severity of the shock load. You will soon learn how hard you need to tighten the collet and how hard to hit it. It's a great justification for buying a(nother) milling machine with a proper quill.

Murray

My mill is R8 and you still have to give it a tap to get the tooling out. I have been looking at this from SPG.

http://spgtools.com/viewtool.php?pid=105

I've just made two self ejecting drawbars for my mill which takes MT3 collets. Why two? Well the first one didn't work out too well! I made a captive drawbar using the threaded top of the spline drive. I made use of an existing 42 x 1.5 mm nut that holds the pulley on and all seemed well except the quill lock is not man enough to stop my drawbar from pushing the quill down when you undo it. Plan B was to thread the top of the spindle as another guy has done. The tool end of the drawbar is threaded M12 x 1.75 mm for the collets so I've threaded the inside of the spindle M14 x 1.25mm and made a nut and threaded collar to suit which is pinned to the top of the drawbar. The difference in pitch ejects the collet when you undo the drawbar.

Watched the video and it shows a sorta cage on top of head which is along the lines of that that I came up with, it'll do the job, but its somewhat awkward in my opinion, wanted something more self contained. Hadn't seen the SPG Tools offering but the power drawbar looks more industrial than hobby, I don't have air and the cost is way to high.

Muzzer, the Tom Senior will do for me, it's not going to get changed, whether or not its got the 'correct taper' LoL

GW.

Hi All

My Emco FB2 uses MT2 tooling and I prefer to use the arrand type tool holders. The tool ejection is simple the spindle top has a collared nut with a hole large enough to get a 10 mm allen key through the draw bar is a long M10 allen bolt when you tighten it it draws the tool into the taper when you slacken the bolt the head hits the underside of the collared nut and ejects the taper. I have a few draw bars M10, 5/16 whit and a plain one for tanged MT 2 tooling all simple stuff and works very well.

Peter

Ok guys, thanks for all info. Done some more searching on the web this afternoon and a 'self contained' type, for the want of another term, looks to need the spindle in the head modifying which is a route I didn't want to go, presume the FB2 has such a spindle from Peter's description. Will make a cage picking up on the 3 allen pins holding the top plate on, extending them with a pierced top plate to allow access and a moveable plate moving below this plate that any drawbar will screw up against to release the collet. Not very pretty but heyhoe needs must.Thanks again.

GW

Against all belief whether hammering drawbar, pushing, extracting tools from tapers, pneumatically hammering drawbar and so on, in fact every method is going to impart stress on bearings. Think logically.

Bearings are cheap even paying for the most expensive quality ones, SKF are only £30 for Super Lux top and bottom not even shopping around.

Hi Graham

One small point make sure you can easily change over the draw bars you will need more than one type. If you use Mt drills or a drill chuck with a tanged MT you need a shorter plain ended ejection bar so being able to change from one to the other easily is important.

Peter

If you don't tighten it up too much you don't have to hit it hard to release!

Just gathering the parts to manufacture one like Stub Mandrel published in MEW 223 for my X2 mill.

Could this be adapted?

(Neil - people do make things from the mag)

* Danny M *

Fine line between to much and not enough tightening. Wonder if any damage would be caused to taper of the spindle if either a collet or chuck started to slip????, Would like to avoid the possibility.

Changing bearings in the head is a topic covered in the Senior Yahoo group but if you can avoid doing it for as long as possible seems sensible to me as many seem to have had some difficulties.

Danny. Don't take MEW so didn't see the article. Have made a start on the extension pins for the top plate so will go with that type now,

There is an useful article in MEW 133 about making and using various adaptors in the Clarkson chuck fitted to a Tom Senior E type mill. Using these adaptors minimises the need to remove the Clarkson chuck.