Machining a Morse Taper in the Gingery Lathe Spindle

[vtsteam]

Just a small project: adding a Morse taper in my 20 year old Gingery lathe's spindle. Actually, I have a number of spindles for this lathe. They are very easy to change out -- basically you loosen 2 set screws, one in the cone pulley and one in the rear spindle retainer pulley, and slide the spindle out. It probably takes a good part of one minute to switch them.

To me the great advantage n the Gingery to changing the spindle rather having just one spindle and adding attachments is that each attachment is always true centered on its spindle.

The one I'm modifying has a 7" faceplate cast onto it. The other day that spindle was mounted and I wanted to turn a wooden pattern blank on my lathe, I hunted up a wood turning spur center I'd bought at Sears years ago, but found it had a #1 Morse taper for attachment. Since this couldn't be gripped in a chuck and I didn't have any spindles with a morse taper, I wasn't able to use it.

Instead I mounted my 3 jaw chuck and turned the pattern with that and the tailstock center -- though it wasn't ideal for the purpose because both ends of the wooden piece needed to be turned down to a smaller diameter than the center section. I got it done by turning the piece around after turning the tail end first, but decided I really needed to add a morse taper spindle to my lathe. Besides the spur center I could also mount other types of center and even collets.

A lookup in Machinery's Handbook showed a Morse taper #1 starts at 0.475" and tapers down to 0.369". So, it seemed  I'd need a 5/16" bit to start the hole, yet stay under 0.369". Ideally it would be a through hole for the length of the spindle, but that's 8" and I don't have a 5/16" drill that long.

Since most of the through bore would mainly be there to accommodate a knockout bar, or collet retainer bar, it doesn't have to be absolutely precise. I could drill from both ends of the spindle, but even then, I think the holes would be about an inch short of meeting. Well we'll cross the bridge when we come to it, at least I had a jobbers bit, and it will drill deep enough for the taper. On with the show!

[vtsteam]

About as deep as I could get it!

[awemawson]

Steve, it is relatively easy to extend the length of a drill bit by welding or silver soldering an extension on, I have several in the cupboard that I’ve done in the past.

As drill shanks are left soft at the chuck end, I mount the drill in the three jaw with this end outwards, and face it off and drill a hole about half the diameter of the target drill. Then I turn up the extension with a spigot of this diameter and press them together for welding.

If you are careful they end up pretty concentric, but I always start deep holes with a shorter drill anyway so when swapping to the extended one it is well guided.

[vtsteam]

Thanks Andrew. I was planning to do it by silver soldering with just a butt joint in my homemade bandsaw brazing fixture. That gives a good alignment, and I don't think a spigot is necessary. Circular saw and carbide masonry bit teeth are silver brazed on with a plain butt joint. On the other hand, I had also been considering making  D-bit, since I've never actually made one before, as an interesting exercise. But, as I said, we'll cross that bridge when we come to it. 

[Sea.dog]

The difference between saw teeth and the inserts on a masonry drill are that they have a support behind them. You're intending to make a joint, with a very small cross-sectional area, that will be in shear.

[vtsteam]

Don't worry, Sea.Dog. I think 40,000 to 70,000 PSI tensile will handle it.

[vtsteam]

Boring the taper with a simple homemade boring bar -- similar actually to a D-bit.

[vtsteam]

Using the spur center as a test plug. The center's taper is blued and offered up to the beginning bore taper.

[vtsteam]

Hitting a little towards the back of the bore. So adjust the topslide angle to slightly more, in relation to the turning axis.

[vtsteam]

Gettin' closer. 

Notice this spur center has a cross drilled hole. So it doesn't actually require a knockout bar through the lathe spindle for removal

[PekkaNF]

Looks like a good progress. Very slender boring bar, but then again small end of the MT1 is small. I tried to stepdril and use reamer for one spindle. I rushed the job and cock it up. Then I found one MT1 extension and used it, worked fine.

If you don't feel like drilling trough hole in the spindle there are many ways for taper tool extraction. I'm sure this is all very familiar for you, maybe some entertainment for someone else. Anyway MT1 hole is pretty small and limiting factor as spindle hole for turning bar material.

There is traditional slot for drift (needs a tang, or some planning ahead). End this weakens spindle.

There is a thread at the front of taper for extraction nut.

And the most simple: Thread at the taper tooling. Not ideal for readymade tooling, but pretty simple to add on self made tooling.

[appletree]

Providing the drill is long enough for the morse taper, use a bigger drill from the other end, as you are aware drills get longer as they increase in diameter

[vtsteam]

Guys, the point of this exercise in a forum thread is to show others how I bore a morse taper in a spindle. If folks would have a little faith in this process we'll get to a result. I'd really like to see some others doing similar simple projects, using their own favorite methods, so this forum has some meat in it and it attracts newcomers, rather than simply expressing doubts during this process, or assuming a lack of understanding of alternative possibilities. Alternatives are great, but demonstrate them in a thread of your own. Then this forum will really come alive again. 

Personally I think this way of fitting a morse taper works perfectly, to me it is the easiest and simplest way to go about it. It requires nothing more than a drill bit, a dead simple homemade boring bar made out of a piece of hardenable rod or even another discarded drill bit, and the part you want to fit. No five figure taper angles to to look up and deal with, no measuring instruments, no step drilling to calculated depths, no delicate expensive Morse taper reamers, no lathe taper attachments, not even angle graduations on a topslide.

My main motivation in showing this kind of thing is to try to help people to realize that they don't need expensive equipment or high precision instruments or complex processes to do precision work. Not that there's anything wrong with those things, but the unconscious belief these days with so much gear available is that you need to buy your way into precision work, rather than understand how, before such purchases were easily available, people were able to achieve quick and accurate results.

Please don't feel squelched, and continue to comment, but do understand that there's a method to my madness, and yep I know there's lot's of ways to skin a cat. 

[vtsteam]

And here is the #1 Morse taper bored, and the spur center mounted in the lathe spindle. This required no measurement and no special tools. Total time to do (minus taking photos and writing it up) was about an hour and a half.

[vtsteam]

The spur center doing some work:

[krv3000]

well dune

[vtsteam]

Thanks, Bob!