Help with drill-Mill conversion

[irving2008]

Cheers, so I probably need a lock nut as well then? The original one just squeezed the inner race on to the step on the shaft.

The other problem is how to drill the hole in to the end of the quill for the chuck lock bolt. I foolishly thought it would fit in the lathe but that also has an M2 taper, Duh

Is it safe/accurate to hold a drill bit (facing up) in a vise and lower the quill down over it?

Safe - maybe if you can hold it tightly - drills have been used as lathes by holding the tooling in a vice and the workpiece in the chuck (I've done it).

Accuracy, its hard to see how you'd get the drill absolutely in-line with the quill. Here's an idea tho.
Acquire a block of MS say 50mm cubed. Drill an M4 tapping hole through the center of one face and tap M4. Put the cube in the vice with the M4 hole horizontal and accessible through the side of the vice jaws then drill down through the centre of the face with the drill you want to use to drill the quill. Remove the drill and without moving the vice put the drill shaft in the hole and lock in with a M4 bolt.

Remove the chuck and lower the quill onto the drill... careful with speeds and use coolant if poss.

You might need to grind a flat on the drill shaft to locate with the locking bolt.

The accuracy depends on how square the chuck was to the quill initially...

So, JohnS, Robin, BillTodd, etc (as real engineers) where's the flaw in my suggestion?

[BillTodd]

I wouldn't call myself an real engineer, or indeed, any kind of engineer but...

That sound like a good plan to me :)

Ross, What's the end of the quill look like? e.g. does it have a centre spot from the taper machining operation?

The accuracy depends on how square the chuck was to the quill initially...

Actually, your clever plan means the new drill 'chuck' will be properly aligned with the quill travel regardless of vice alignment.

[BillTodd]

Is this an issue if there is a centre spot?

Just makes it easier :)

[irving2008]

Added thoughts...

Size of block = size of drill x 2-ish need enough metal for the locking bolt to remain rigid

If drill shaft < drill size (as it might be if its a big drill) then drill out the hole shaft sized first then use the proper drill to bore down 10-15mm to provide a locating seat... then remove drill etc as before....

Ally instead of MS... can't see why not, maybe go for a bit more 'meat' on it. Only issue might be getting a good lock on the drill... if you never want to use the drill again without some effort you could try loctite in the hole!

thanks for the +ve feedback

[Ross77]

M5 even, so long as you use a good quality screw and key. HT would be overkill, just avoid stainless and cheapies.

Thanks Robin. HT ? high tensile?

10mm slot width or height? It's ok to engineer a twist fit solution.....

10mm wide. Approx 30mm high. What do you mean twist fit :question:

[Robin Hewitt]

Thanks Robin. HT ? high tensile?
10mm wide. Approx 30mm high. What do you mean twist fit :question:

High tensile, yes.

No extra space in a knock out slot to twist into, they are cut to fit the taper tang.

Hopefully you will have room between the spindle nose and the chuck so you can slip a fat spanner in the gap to lever it out.

OTOH you can cross that bridge when you come to it

[Ross77]

Yeah not worried about getting it back out. just as long as it stays in:dance:

Just cut a piece of steel to go in the knock out hole, but cant find my M5 tap, why is always the one you want that disapears in to thin air......

I'm going to try this route first, If it wont hold then I'll drill up into the quill from M8 bolt. I'll get some new taps tomorrow and a selection of bolts.

Let you know if it works................

[Ross77]

It will be a miracle if i ever finish this... with every day comes a new problem

Drilled and tapped the new key for M5 but cant find any bolts long enough. (125mm). Would studding be ok? The other option is to make up a small drawbar 8mm dia. to go thro the chuck then turn down the end for an M5 thread, problem is making it strong enough and providing some sort of slot in the head for tightening.

The next challenge is deciding wether to cut down the main post and fix the head at a set height or allow it move up and down to suit the job, like a proper mill I will need to sort out a better clamp than the existing grub screw arrangement , may be cut a slot and then bolt up to pinch the main post? would this help remove the current play, and provide an accurate reposition when moved?

[BillTodd]

Why did you abandon plans to drill & tap the quill?

Although, I think M5 should be OK. (you won't be taking it in and out all the time)

would this help remove the current play, and provide an accurate reposition when moved?

Might work.

I'm happy with the way my [ame="http://www.cnczone.com/forums/showthread.php?t=70099"]wishbone stabiliser [/ame]works if you want to copy.

[Ross77]

Why did you abandon plans to drill & tap the quill?

Cost..lol the depth into the quill is over 100mm so I needed to buy extra long taps and drill bits. In hind sight it would have been worth it tho as it is definatly the best solution. M8 bolts over 100mm no problem.

Try the cheap option First eh.

Cheers for the stabiliser idea, Not quite what i meant tho. not bothered about rotational postion. I was refering to the the existing head rocking on the post (out of tram(I think..))

In the picture of yours, is that the locking bolts I can see at the back of the head casting?