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Machining a Morse Taper in the Gingery Lathe Spindle

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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!

About as deep as I could get it!

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 Iíve 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.

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.  :zap:
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.


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