Using the flat way as a replacement for a worn V way.

[TRC]

V way of the tool side is worn. It's my first lathe and I did "the mistake".

To make it short, the previous owner likely didn't knew the difference between way oil and the crap he smeared all over the lathe.

I'd like to use the flat way of the tailstock. This one probably isn't badly worn near the chuck.

I was planning to use a bronze shim to raise the carriage about a 0.005 below the height the ways are at the end of the bed.

What I want to know if it's a good idea, if someone have tried and if a single, flat sliding will be enough.


The lathe in question is a 16".

 

[michiganbuck]

I don't understand your plan. Running bigger work the effect of some bed washout may not be as severe on the part size, so that should be considered.

 

[Gard]

I think you would have more problems trying to support the saddle on the tailstock flat than you will have using the worn V way. Do you know how worn it is? How tall is the ridge on the saddle or V way?

 

[john.k]

Using the inside flat would make for considerable overhang,and maybe vibration..........the saddle is also likely to lift on the rear slideway ........it might be an interesting experiment to grind the front V away completely ,and reconfigure the saddlle as a flatbed lathe.

 

[johansen]

Support the carriage on the tailstock flat way and then re scrape/ grind the front v ways to match it.

You could even take your compound off, build a 45 degree angle plate to hold it to the cross slide, and use the compound hold a tool post grinder off the edge of the carriage. It will be cantilevered out a good distance so you will need a counter weight.

Make the angle plate reversible so you can move the grinder to the other side of the carriage.

Once you get to .003" or so.. quit while you are ahead, unless you can make your own kingway type fixture to measure the twist and distance between the v ways at both ends of the lathe.

You may need to re scrape the carriage, but If you are careful to remove the same amount from both sides of the V way, you won't need to rescrape it very much.

Next thing to do is relive the middle third of the carriage.

 

[TRC]

I don't understand your plan. Running bigger work the effect of some bed washout may not be as severe on the part size, so that should be considered.

I want to use the tailstock flat way with the carriage, since the v way is worn a bit. And I need to work on some small part.

Do you know how worn it is? How tall is the ridge on the saddle or V way?

The ridge is about 0.05" on the V way. Is it bad?

it might be an interesting experiment to grind the front V away completely ,and reconfigure the saddlle as a flatbed lathe.

If only someone was willing to try this out on their lathe...

Support the carriage on the tailstock flat way and then re scrape/ grind the front v ways to match it.

You could even take your compound off, build a 45 degree angle plate to hold it to the cross slide, and use the compound hold a tool post grinder off the edge of the carriage. It will be cantilevered out a good distance so you will need a counter weight.

Make the angle plate reversible so you can move the grinder to the other side of the carriage.

Once you get to .003" or so.. quit while you are ahead, unless you can make your own kingway type fixture to measure the twist and distance between the v ways at both ends of the lathe.

You may need to re scrape the carriage, but If you are careful to remove the same amount from both sides of the V way, you won't need to rescrape it very much.

Next thing to do is relive the middle third of the carriage.

Are you referring to something like this:

I'll try this in last resort. It doesn't seem to be a bad idea (if well done), but I will try everything else before grinding/scrapping the bed and the saddle, since it's not a reversible choice.

 

[Gard]

I think most people would consider 0.050 " of wear on a lathe V way to be a lot. I guess it depends a little on how you are measuring it. Some photos might help. I recently went thru this on a SB 10L lathe with a 4' bed, the carriage would be 0.025" lower near the chuck than at the far end. I had the entire bed planed so all surfaces are now straight and parallel, cost was $250. https://www.practicalmachinist.com/forum/threads/how-bad-is-this-sb-10l-bed.403510/

 

[Peter from Holland]

Bedwaywear if about the same in front or the back ways is trubblesome with small diameters much more as with bigger diameters
It has little effect if the cutting tip is a bit higher or lower on a bigger diameter
However if the carriage tilts because of more wear at the front or back that would be a bigger problem
That moves the cutting tool in or out giving a 2 times as big difference in diameter
So consider scraping the less worn ways so the carriage stays level perhaps

Peter

 

[Richard King]

How about showing us a few pictures. Tell us what your plan is for using the lathe. Do you use the tail-stock to support the end of shafts? Is the lathe bed hard or soft? Is it an Import or American made machine?

 

[TRC]

Sorry for the late replies, I was sick this weekend.

Some photos might help.

On the pic with the calliper.

How about showing us a few pictures. Tell us what your plan is for using the lathe. Do you use the tail-stock to support the end of shafts? Is the lathe bed hard or soft? Is it an Import or American made machine?

Soft bed, 1942 16"x36" (117C) SBL, imported straight from freedom land to make ammunition for the Canadian army. Soft way. The tail-stock is not level yet, so no, I dont use it. (I'm not doing long pieces yet, I know the 3 time diameter rule).

I'm using the lathe to do a bit of everything, but mainly small diameter stuff. I'm an engineer, and the kind that make machinist refuse my order due to my insanely small part. Of course, I'm not expecting to reach my target diameter of around 1/16 with this lathe as it currently is. I'll mount another spindle in front of the first one, in such a way that I can reach 20k rpm or so.

So consider scraping the less worn ways so the carriage stays level perhaps

I'm no expert on lathe science, but wouldn't it be a better idea to scrape the less consistant and worn ways, so that they are parallels with the less worn ones?

Here are the pics

https://imgur.com/a/yO9DI6o

In case you've never used imgur, you can navigate those with the arrows on the pictures.

 

[Richard King]

That's know as "the South Bend Ridge" very common on soft bed machines. The saddle that runs against it is shorter so if the bed is worn 2 times more. I use the tail stock ways to measure the amount the bed is worn. Take apart the tailstock and use the bottom as a sled to mount a mag base to and put the indicator on the saddle ways as close to the headstock or around the headstock and zero the indicator.

Then slide the tailstock sled down the bed to measure all the saddle ways. The tail-stock never wears in front of the saddle, so the TS ways will be dinged up and you should file or stone the dings (burrs) Logically the bed will be worn gradually and get less you go down the bed. The inside of the front V will be worse. Check the bed and magic mark how bad it is and show us. Like I said if you take off the saddle and measure the South Bend Ridge on the underside of the saddle it usually is 2 times deeper then the bed. Once we know the total amount of wear we can give you a good estimate on what to do next.

You will not be re-inventing the wheel here as all types have been done tried in the years people have been rebuilding machines. I would not consider grinding the bed in the you tube show. There was a guy who used the TS ways and making a L bracket that holds the lathe compound with tool bit to plain the bed on You Tube. I helped my Dad do something similar in 1966. It was a real pain and we were pro's. Once we got it close we scraped it. We had straight-edges, gages and knew how to scrape. You would be better off sending it to a grind shop like Cash Masters or someone with a Planner like Steve Watkins.

 

[john.k]

When you grind a bed with the owner looking on,often they are dismayed that whats being ground away is the good part of the bed............the worst worn part is the last to start to grind,and that doesnt seem right.............and so we have all the u tube videos of guys grinding the scored ways under the chuck until they are nice and clean..........they are actually making the wear worse.

 

[lucky7]

Where in Canada are you?

A South Bend like yours is relatively easy to re-align after grinding the bed. Just shim down the lead screw to account for amount of wear/grinding of bed, and amount of scraping of saddle. Many other lathes without the ability to move the lead screw would require you to build back up the saddle with turcite or equivalent.

Before putting any time or money into an older lathe like yours, I’d want to know condition of rest of lathe. Is it worth it? Could there be other, better condition lathes in your future?

 

[Richard King]

I just looked up this online, they're in Quebec. They have a surface grinder it says. https://www.meyertool.com/meyer-tool-canada/

 

[awander]

If you use a flat way to replace an existing V way, what will then locate the saddle in the X direction?

 

[TRC]

Where in Canada are you?

Before putting any time or money into an older lathe like yours, I’d want to know condition of rest of lathe. Is it worth it? Could there be other, better condition lathes in your futur

Quebec, around Montreal.

The spindle and its bearing look fine, I think these where the only that where not greased up with god know what.

other than the ways, the cradle and its shaft are badly worn out. Mine is a 1942 model, from before they started using bearing there. I made a post about that too. Fortunately, it should be an easy fix, since it`s just a new shaft and 4 bushing that need to be made.

The gears seem to be fine. Some tooth are visibly thinner than they should be, but they seem alright.

The half nut and the cross slide nut are about to die... these are only a fine wall away to be thru holes. These are on my "to do before they break" list, since these are expensive.

Other than the wear, no rust. Just a load of grease and gunk everywhere, in every orifice imaginable. I hope it's worth it, since this thing is about 3k less than any other lathe in the area.

I just looked up this online, they're in Quebec. They have a surface grinder it says. https://www.meyertool.com/meyer-tool-canada/

Screw the grinder, I'm gonna have my ways plated back to original thickness with that https://www.meyertool.com/platinum-plating/

But more seriously, these guys are about 45 min of walk from my place. If they don't charge too much for a good grinding, they would be a good solution.

When you grind a bed with the owner looking on,often they are dismayed that whats being ground away is the good part of the bed............the worst worn part is the last to start to grind,and that doesnt seem right.............and so we have all the u tube videos of guys grinding the scored ways under the chuck until they are nice and clean..........they are actually making the wear worse.

I dont follow you... Are you saying that they don't remove the material at the right spot and doesn't make the ways straight?

If you use a flat way to replace an existing V way, what will then locate the saddle in the X direction?

I was not planning to get rid of the v way. There is two V way for the saddle. one of them is more worn out than the other. If I use the flat way, then the other V way would be entirely responsible for the X direction by supporting both side of the V.

 

[AlexyL]

@TRC i just called these guys a few minutes ago, they rebuild lathes of all sort and can grind, scrape, re align your lathe if you want to. I’m waiting for them to call me back to see how much they would charge to re grind my saddle and scrape it on my 13”.

http://www.specialitesam.com/fr/cnt/nos_services/usinage_et_rectification.htm

Cheers!

 

[Richard King]

Looks like a GREAT company. Good luck

 

[TRC]

@TRC i just called these guys a few minutes ago, they rebuild lathes of all sort and can grind, scrape, re align your lathe if you want to. I’m waiting for them to call me back to see how much they would charge to re grind my saddle and scrape it on my 13”.

http://www.specialitesam.com/fr/cnt/nos_services/usinage_et_rectification.htm

Cheers!

Can you share the price for your 13"? The 13" is not too far to the 16" in size, so it would give me a good approximate.

 

[john.k]

Be sure you are seated when the price is revealed......in a slight tangent,the guy I reground some lathe beds for last year died suddenly last Monday.....suspected C19 ......he was the fittest 78year old imaginable,and used to run marathons .