Oh boy, you guys are gonna hate me.

[RafaelMarujo]

I think that the “height” of the tool may be misleading. One could certainly imagine a lathe with a non-horizontal cross slide. Let’s say it moves upward along a 10° incline as it approaches the spindle axis. So the tool height would change relative to the (horizontal) carriage ways, but as long as the tool starts in the right place, it will move along a diameter of the workpiece. To set the tool height, one would be measuring from the inclined cross ways, not the horizontal carriage ways.

Such a configuration is perhaps more complicated in some aspects for setup, but should be no different in operation.

It does seem like something is off, as wear alone cannot account for the discrepancy you have noted.

Right that's what been eating my brain, how would almost 5mm wear on a machine like this

I was thinking about that too.
In engineering one of the ways I test a theory is to take it to extremes. If it holds true at the extremes them it likely is true at the small scale that is hard to see.
So in this case if the cross slide were at a 45° angle the height of the tool tip above the bed ways would obviously change as the cross slide is moved. Even though the 45° inclined cross slide would function just fine. What is important is that the tool tip follow a straight line that goes thru the center of the spindle. The angle of that line is irrelevant, just like the lathe being level is irrelevant, In theory it would work just as well bolted to the wall. What is important is the the mounting of the lathe does not impart any twist in the bed.

So after more thought, What is important is that the cross slide moves in a straight line that is 90° to the Center Line of the spindle. As long as the cross slide is moving in a straight line it does not matter what angle it is at. Once you adjust the tool height to spindle center line the tool will always hit the diameter of the part it its tangent point, which is what you want.

As far as the dial markings being way off, are you sure the lathe is calibrated in mm and not in inches? Are you taking up all the backlash before you measurement? Some lathes will move the tool tip 1mm per mark which means that it will remove 2mm from the dia. Some lathes are the opposite where the graduations on the dial are for how much is being removed from the diameter of the part. There is usually something real near the dial to tell you what the calibration is, If not then you need to measure it to verify what you have.

Ohh I see OK that makes sense... I was picturing in my mind the crosslide going forward but also upwards, but it makes sense that it always traces a straight line tru the center!
The dial yeah I'm pretty sure thats in mm because is never misses by a lot, just enough to be as annoying error, and also 1mm in the dial is 1mm off the workpiece.
With the wear thing accounted for what should I do to correct the bad surface finish and the taper its cutting?
It's cutting about 0.03mm taper in about 100mm

 

[Flyinfool]

The taper and the surface finish may be two unrelated issues.
First is to figure out the surface finish. a good surface finish will make for more accurate measurement for getting out the taper.

What material are you cutting and what kind of tool are you using? Pictures of the tool and surface finish will help. along with speeds feed and depth of cut.

 

[RafaelMarujo]

The taper and the surface finish may be two unrelated issues.
First is to figure out the surface finish. a good surface finish will make for more accurate measurement for getting out the taper.

What material are you cutting and what kind of tool are you using? Pictures of the tool and surface finish will help. along with speeds feed and depth of cut.

OK I will clean everything, reassemble the lathe and chuck and document everything...

 

[Flyinfool]

Before you put it back together, re-cut all of those oil grooves so that oil can actually get to where it is supposed to be. That will slow down any more wear.
I almost wonder if the saddle did not have a defect in the casting and they just kept grinding at the factory till it worked properly?? If there was 5mm worn off that surface I would expect to see a lot more galling and other nastiness.

 

[RafaelMarujo]

Before you put it back together, re-cut all of those oil grooves so that oil can actually get to where it is supposed to be. That will slow down any more wear.
I almost wonder if the saddle did not have a defect in the casting and they just kept grinding at the factory till it worked properly?? If there was 5mm worn off that surface I would expect to see a lot more galling and other nastiness.

That's possible I guess yeah, I will do that...
Boy I was wanting to machine a big piece of cast iron on the shaper </3

 

[sdelivery]

It is not that expensive to glue on some turcite and get it back to something a little more useable.

 

[Richard King 2]

I got an email back from Adam...I was mistaken, he's in Spain, but said he is about 14 hours drive, but willing to help as much as he can

 

[Richard King 2]

Wow is that worn. When the oil groove is gone it is bad. It is important to bring the saddle back to the proper height and if you can't find Turcite. Look for a Phenolic laminate grade linen weave. It comes in different sizes and is glue on just like turcite. It is what we used before turcite got popular. A very simple way to test the saddle alignment is to indicate where the carriage bolts on. You can put a mag base on the front side of the bed and the plunger type indicator on the underside and shim up the saddle with plastic shim stock super glued on and the slide the saddle to and fro. Then use that figure to calculate how much angle it is off plus the ridge you depth miked. Look inside the brass nuts and look at the feed screw thread, I suspect they are sharp like a bolt thread. They should be square or acme threads. It the saddle bottom is that worn, then I predict the saddle top is worn a lot in the middle of the flats and dovetails are worn a lot too. What is the travel of your shaper? If you had a dovetail cutter, you might be easier to mill the top flats and dovetails. You will have to raise the cross-slide too. I asked about the headstock as those heads sitting on flats can be turned so you can turn straight. The bed is worn on the flat front near the chuck and it turns a taper big on that end. If your not wanting tight tolerances you can turn the head so it turns a test bar straight. You loosen the headstock and it probably has a pivot pin to move the head to turn straight. Many Asian lathes are built that way and it makes it so much easier to align a worn bed headstock. I also suspect the spindle bearings are bad. I can tell you how to test them, but tomorrow. It's bedtime for me....lol...

 

[RafaelMarujo]

Wow is that worn. When the oil groove is gone it is bad. It is important to bring the saddle back to the proper height and if you can't find Turcite. Look for a Phenolic laminate grade linen weave. It comes in different sizes and is glue on just like turcite. It is what we used before turcite got popular. A very simple way to test the saddle alignment is to indicate where the carriage bolts on. You can put a mag base on the front side of the bed and the plunger type indicator on the underside and shim up the saddle with plastic shim stock super glued on and the slide the saddle to and fro. Then use that figure to calculate how much angle it is off plus the ridge you depth miked. Look inside the brass nuts and look at the feed screw thread, I suspect they are sharp like a bolt thread. They should be square or acme threads. It the saddle bottom is that worn, then I predict the saddle top is worn a lot in the middle of the flats and dovetails are worn a lot too. What is the travel of your shaper? If you had a dovetail cutter, you might be easier to mill the top flats and dovetails. You will have to raise the cross-slide too. I asked about the headstock as those heads sitting on flats can be turned so you can turn straight. The bed is worn on the flat front near the chuck and it turns a taper big on that end. If your not wanting tight tolerances you can turn the head so it turns a test bar straight. You loosen the headstock and it probably has a pivot pin to move the head to turn straight. Many Asian lathes are built that way and it makes it so much easier to align a worn bed headstock. I also suspect the spindle bearings are bad. I can tell you how to test them, but tomorrow. It's bedtime for me....lol...

Yes I will do that, I'm more than grateful for the time you already dedicated!!
Flyinfool also has a really good theory, if you can read the comments and give your opinion that would be awesome..
My shaper is my pride and joy, she's a big ol meanie and has more than enough travel for the saddle to fit
I thinks she's also pretty accurate, I don't know about the usual tolerances for shapers but I can usually cut about 200mm long with about 0.02mm deviation... The saddle won't fit on my mill tho..

 

[Richard King 2]

You may ask management here to switch this thread to the rebuilding / reconditioning forum. More members will benefit from it there.