Lathe Thread Adapter Question from a Noobie

[NewfoundlandLaw]

Hey All

So, after 6 months of using my King Variable Speed lathe, (1218VS) I've decided to upgrade to a 220v Laguna Revo 18/36. The King has been great but I want something more substantial and I've used the Revo and love it.

My question is this: I have lots of 1"x8tpi accessories that I love, but the Laguna is 1-1/4x8tpi. Is there any downside to just using a thread adapter or am I better off buying all new accessories?

Thanks All!

 

[lorbay]

They are ok. But the more things ( pieces) you put between the head stock and your Chuck increases the chance for runout. Not a really big deal on a wood lathe but it is horrendous on a metal lathe


Lin

 

[monophoto]

As Lin says, there is a risk that a thread adapter might not be perfectly machined and therefore contribute to runout. In addition, thread adapters consume a couple of inches of effective bedway - so if you are moving to a lathe with a 36" bed, you might only be able to use 34" of that length.

However, the other side of the coin is that replacing your existing tooling entails cost.

I upgraded from a 3/4x16 spindle to a 1x8 spindle, and made conscious decisions about individual tools. Basically, my logic was that if a current fixing would only be used for relatively short spindles, then it was unlikely that any incremental runout would make much of a difference, so those could be handled with an adapter. But fixings that would be used for longer spindles where runout would be amplified by the length of the spindle needed to be upgraded to avoid the need for an adapter.

So the bottom line is that specialty fixings (eg, a wine stopper mandrel) could be used with an adapter. My chuck actually was a 1x8 model with an adapter to fit on a 3/4x16 spindle, so that was an easy change for me.

Final thought - this is something where you might choose to invest a small amount into an adapter initially so that you can use your new lathe, but with the expectation that over time, you would upgrade those accessories where using an adapter introduces compromise.

 

[JimB]

When I upgraded to my PM3520B I had the same issue. I bought a Stronghold Chuck for doing large bowls so I wouldn't need an adaptor. However, for some of my other accessories, including my small chuck, I use an adaptor when using them on the PM however Since I still have my Jet mini lathe I still want 1x8 threading on some of my tools.

I actually have 2 adaptors. One is 1-1/4 x 8 to 1x8 and the other is 1x8 to 1-1/4x8. That way I can use any tool on any lathe. The adaptors haven't caused any problems with runout or any other issues. I bought mine from CSUSA.

 

[moke]

I did exactly the same thing you are doing about a year and a half ago. I think I got the adapter from PSI.....if I recall there were a couple of grades and I got the better one. Who knows if it is really better or not? I used to drill on the lathe with the adapter and a PSI drilling chuck with no issues. The Revo has a long throw on the quill so it was easy, but since I have gotten a metal lathe and I drill on it. ( I really don't know why, the newer toy, I guess)
The Revo is an awesome lathe....a big beast, and very smooth. I got it right after they came out, and have not had any complaints to speak of since. For the two subsequent Christmas's after, I asked for the Laguana lights each time, so now I have two and I have to tell you that is a little extra that really makes the lathe. PM if you have any other questions, I have set up several for my friends. I have only seen one bad review since they came out....everybody I know that has one loves it.

 

[monophoto]

I used to drill on the lathe with the adapter and a PSI drilling chuck with no issues.

OP was asking about thread adapters. Mike's response touches on a related issue - morse taper adapters.

It is possible to purchase adapters to fit between an MT2 spindle, and an MT1 fixing (such as a jacobs chuck or a pen mandrel). I think it is also possible to find MT3-MT2 adapters. I don't know if it is possible to go in the other direction. The issue is that if the taper on the fixing is smaller than the taper on the lathe spindle, then the adapter can be a simple sheath. That is, the smaller taper will fit inside the larger taper. But if the taper on the fitting is larger than the taper in the lathe spindle, then the adapter has to be fairly long. That again raises the issue of runout.

In addition, one has to worry about the fact that if you use adapters to mate incompatible tapers, you now have two tapers to be concerned about. All it takes is a little bit of crud on one of the tapers to cause intolerable runout.

When I did my upgrade, I recognized that I use my jacobs chuck a lot, and I didn't want to have the hassle of dealing with adapters. Fortunately, most jacobs chucks consist of a chuck body and an arbor - the arbor is double ended with a jacobs taper on one end (JT-33 - to fit into the chuck body), and the morse taper on the other end. And it's possible to purchase relatively inexpensive replacement arbors so that a jacobs chuck originally purchased for use with a smaller lathe can be 'modernized' to work with a larger lathe.

 

[moke]

Louie, I was actually talking about thread adapters...I use the PSI drilling chuck, it is 8x1. The Revo is 8x1 1/4. But for as big as the Revo is, it is still MT2 both in the headstock and tailstock. On the revo I turn both between centers and on a mandrel, the mandrel I have is 8x1 with the mandrel screwed into it and I use the thread adapter for that too.
On my metal lathe the headstock is MT4 and the tailstock is MT3, so I have more adapters than you can imagine, not to mention a mt3 extender that moves the jacobs chuck out more over the carriage.....to find more and more precise adapters, you might look on line at Victor Machine.
Just my .02