Jet 10x24 Compound Slide

[Erevojoe]

ok, I've posted questions about this lathe before but I'm starting over with a new post. I've had enough trial and error to phrase my questions a little bit better and might be able to understand the answeres this time.

I have a 1976 jet 10x24 that I've been rebuilding for about two months now. The compound rest/top slide was missing and I tried finding a piece from another unit that would work but now I'm just going to make a new one. My biggest mistake so far was thinking that the top of the compound should be level with the centerline of the spindle. I bought a used unit, got it bolted up and then realized that with the tool post and the tool holder, the cutting edge was now 1.5" above the center of the chuck. So, 1/2 of that money was waisted cause cutting that much material out of the new slide would not leave much material left between the tunnel for the threaded rod and the area behind the tool post. So here are my questions.

1) what is the standard gap between the top of the compound and the center of the chuck on a 10" lathe

2) what material is good enough for a compound slide? Ductile is too rich for my blood. I'm looking at either a 2024 al or 6061 al. I might go with a cold rolled steel. I'm new to this. The old one looks like it was cast iron and the new one looks like a high grade cast ductile. Looking at basic specs of those materials I'm guessing any material with a tension strength over 40k would be good enough. I just want to make sure I'm using something strong enough, but soft enough to be the weak link in the event of a crash. I'll take s broken slide over more expensive parts any day of the week.

Thanks.

 

[george wilson]

I used to have that very lathe,but that was in the early 70's. A great little lathe,it was!

However,I have no idea at this point about the measurement you seek.

My reply is to advise you to NOT go with aluminum by any means. Go with mild steel at the very least,if you don't want to go with dura bar cast iron. Aluminum will eventually start to gall on the sliding surfaces,and you must be sure to keep mild steel oiled. Cast iron is best because it has a built in lubricant of graphite and is very hard to ever get to gall(though it IS DEFINITELY POSSIBLE ON ROTATING SHAFTS if you don't keep them lubricated).

I used to have a spare compound for your lathe model,but years ago it was sacrificed when he compound on a Sharp 13" lathe cracked across the "T" slot. I had to adapt the Jet compound to fit the Sharp.

I do not think the compound for the Jet was much more than 1" thick,and the swivel base was about 3/8" or 1/2",if that helps you any. The compound could have been a little over 1". I just can't recall by now.

There is a member here who lives in Lanexa,Va.,who owns a Jet 10 x 24",but I can't recall his name. You might start a thread advertising for his name.

 

[Erevojoe]

Thanks for thanking the time to set me straight. Although I haven't been able to use it much yet, I have fallen in love it's this lathe. I spent ten years as a r&d mechanic for Harley Davidson and one point I was in the middle of the swamp with nothing but a smithy 3in1 and my own intuition. Even thou my only experience with cutting metal was in tech school, I learned to hate that machine real quick. This machine was just small enough for me to get into my shop (after disassembling everything except the headstock) but rock solid compaired to any other hobby lathe I've seen. Power cross feed, backgear, reverse threading tumbler, it's great. My photobucket app keeps crashing so I can't post pics anymore. Maybe I can get my iPad updated and fix that soon.
Set me straight again. I think y qctp may be for a larger lathe as well, it is huge. But as long as I make a slide that works with it it's ok right? the only really important thing about this is that it's strong enough, not above or below the center line, and any moving parts move straight and true.

Should the tool holder of the qctp hang off the top Slide or should it sit on the top of the slide. I have searched for pics of them being used but I find both. i am going to set it up so the top slide is just far enough below the center line of the spindle that my tool holder will be lined up with center when it's sitting on the Top surface of the slide. The base I'm using is very thick so I am going to use it as my final cut. If I get my math off a little bit, I'll just take it out of the bottom of the base. It's at least .350" thicker than it needs to be.

 

[george wilson]

I am not quite sure what you are asking. The blocky body of the qctp sits centered over the T slot on top of the compound. It couldn't be in any other position,with the hold down bolt going up through the center of the qctp's body. The tools therefore necessarily DO hang out to the side of the qctp.. If they did not,the qctp's body would hit the metal you're trying to turn. Making cut off's would be impossible.

But,here's a valuable piece of advice: NEVER let the compound hang out past the dovetail until there is no support UNDER the T slot. That is how the compound on the used Sharp 13" lathe got broken. It apparently was cracked nearly through when I bought that lathe,but nobody expected that,or noticed it. So,one day it just let go. No one in my shop would have been such an inexperienced machinist as to let that happen.

This is another excellent reason to NOT use aluminum for your compound,since it would be broken a LOT more easily than making one from mild steel. I would not hesitate to make the compound out of mild steel,because the sliding of the compound's dovetail is so limited,and so slow that with mild steel it will never gall,especially with even just a small amount of oil. The only time you will ever move the compound very much is when you are turning a taper. This is also the only time when you might have to allow the T slot to stick out beyond the support of the swivel base beneath it. Mild steel would actually be stronger than cast iron in resisting breaking. It could bend,but it won't just crack off like cast iron.

As to vibration: Cast iron is the best metal for damping vibration. But,for this single purpose,I doubt seriously that making a mild steel compound would add in any noticeable way to chattering. The cast iron bed is the most important component of your lathe as to damping vibration.

 

[Jester966]

"going to set it up so the top slide is just far enough below the center line of the spindle that my tool holder will be lined up with center when it's sitting on the Top surface of the slide"

If I understand you correctly - I recommend against that. While the idea would help rigidity, you need some allowance for adjustability with the QCTP for using a variety of tools.

 

[AR1911]

The correct QCTP for that lathe is AXA or 100.
I'm real surprised you can't adapt a Grizzly slide to that thing.

 

[george wilson]

Make it so that the tool holder is about 1/2 way up the tool post when a tool mounted in it touches the center height of the lathe.

I never used anything but the old fashioned lantern tool post on my Jet,so I can't advise you about the size to get. I'm sure an A or B would be fine.