Never used an extension, I presume here you have a 2MT socket in your tailstock barrel and want to use a 2 to 3 MT convertor. What I did was I made a #3MT tailstock barrel, forced upon me by the fact that the ex-school Emco Maximat S11 had suffered at the hands of the 'yoof' and the tailstock barrel had been detached and used for unimagined purposes (or just thrown in the local canal!).

The barrel just happened to be 30mm diameter and in my 'scrap box' was a Go Kart back axle of 30mm ground bar (with a hole through it) but even better it had a 3mm keyway along the majority of its length. The tailstock had a 2.5mm key in it to radially locate the barrel – so a quick re-make of that to 3mm and I had the perfect new barrel. I made a PB bush nut to fix in the end of the tube for the leadscrew, and then reamed the barrel to #3MT (purely because the hole through the original axle suited a #3 MT minor diameter). The nose of the barrel protrudes about 40mm out due to the #3 MT would otherwise interfere with the keyway.

It's not too difficult to make a new barrel – and you can make it as long as you like. On my other machine (a Raglan LJ) I have a capstan operated tailstock, home made again, but using a Raglan 5" capstan tailstock casting for the rack pinion housing.

Martin

There is no reason not to if the work requires it.

I have a '2MT to 2MT adapter' for my Myford. I find it very useful for some operations such as tapping or using small, and therefore short, drills. I bought it from Chronos. I didn't have great expectations for accuracy as it's almost certainly Chinese but was pleasantly surprised. The runout is about a thou. The resistance to lateral forces is not great, as you might expect, but it could support light turning eg clockmaking. It seems fine for axial loads though.

Andrew

If you are worried about droop or wobble, and if space permits, you can always snug the fixed steady fingers onto the extension.

Nice picture from john showing the main disadvantage of an extension in the tailstock.

Its too darn long! So you can't leave it in place all the time.

Especially if its a same size to same size one.

Due to the need to accommodate both MT shank and tang in the extension barrel you have around 4 inches or more of extension which is not only rather more than you need but also unnecessarily magnifies any alignment errors.

Pretty much all of our home workshop size lathes tend to be short in the tailstock and of limited travel. Around 2 to 2 1/2" of useful travel before inadvertently popping the tool out on retraction is common and just not enough in practice. Main reason I swopped my SouthBend Heavy 10 for a Smart & Brown 1024!

Many years ago one of the guys on the SouthBend Forum described his modifications to increase tailstock poppet travel to, I think, around 3 1/2" or a little more. He screwed an extension piece on the back of the tailstock to accommodate a longer poppet and feed screw. As I recall it he made the extension bore a little larger than the tailstock bore proper to avoid potential alignment issues.

As its a permanent modification you could ream the whole bore after fitting to ensure accurate sizing and alignment and make a larger poppet to suit.

He reported that the extra inch or so gave enough travel to eliminate reach over the cross slide issues and made drilling deeper holes much easier.

Its what I would have done if a bout of bad temper had not coincided with a £££ offer for the Heavy 10 the same weekend as a 1024 appears within collection range!

Clive

Hi, I have a 2 to 3 step up one that I have used on my Boxford for larger drills that can't be used in the 2MT tailstock. But the thing is, knowing the limitations of such use and basically not trying to push it through too fast. haven't had any problems thus far, but it's not a regular occurrence and I don't expect to drill double the size hole, about 1-3/8" in a piece of cast iron is as big that I have done.

Regards Nick.

At a quick glance there's nothing wrong with my hands, apart from a few minor cuts. But those are inevitable when manhandling large sheet metal parts on and off the mill.

Andrew