Rectifying the saddle of the lathe.

A lot of talk and a bit of milling work.

[@christophercullen1236]

Your last couple of videos have shown me how to fix my " cheap " Chinese lathe thank you. Christopher from Down Under

[@Rustinox]

Go for it, Christopher!

[@TheRecreationalMachinist]

Following with interest - my mini lathe has the same issue. I've just worked around it but one day I may try to improve it...

[@Rustinox]

Thanks. It will be in next video.

[@charleskutrufis9612]

This one scares me, I can't imagine doing this to one of my machines. A man has to recognize his limitations. You certainly are far and away out of my league. Best of luck , I'll be watching. Thank You

[@Rustinox]

You can do this, Charles. Take your time and step by step. It will work.

[@alro2434]

Thanks, very nice video. I'd try twisting it, one direction, then test, then twist in the other direction, then test, just to see if it straightens out or there is still a spring/latent twist in it that still wants to come out & drive you crazy trying to chase it. It may still be a moving target after all these years! Also, thanks for the 'Anti Scraping' message! If engines can lube their rings with cylinder surface scratches retaining lube, I think ways can do it too!

[@Rustinox]

It's still not perfect but it works.

[@jimzivny1554]

A huge part of the job is problem solving and that's how we learn, you're doing a great job

[@Rustinox]

You're right. Thanks Jim.

[@andrewdolinskiatcarpathian]

Thank you for sharing your thought process and how you are tacking the problems you are encountering. If there is one person who will find a solution, that person is you. Keep going, you can do it. 👏👏👍😀

[@Rustinox]

In the meanwhile it's fixed. It will be in next video.

[@garychaplin9861]

Hi Michael, I see comment about warping of the saddle being caused by improper ageing. Ageing the casting does little to relieve the stress from casting, heat treatment properly done is much more effective. however more expensive so not always done. I would also be checking the apron mounting surface to ensure it is flat, if the casting has bowed then the mounting surface is likely to need work. I would also check the top surface of the apron and the hold down casting to ensure that the warp has not been caused by those surfaces not being flat causing the saddle to bow,

[@Rustinox]

Thanks Gary. I fixed the problem.

[@allenhunt3070]

Hi Michael, I'm confident that you will sort it out and get your lathe running much better, because you always stay on course till you work it out. Enjoyed the show! BTW, on the fireball tool channel, he tested the effect of back dragging a file using a shaper and he didn't fine it a significant issue.

[@Rustinox]

I already fixed it. It will be in next video.

[@624Dudley]

Hello Rusti, I admire both your ability to analyze a problem and your courage to rectify it. 👍

[@Rustinox]

No courage needed. Just go for it.

[@bearsrodshop7067]

Well Michel, after 2 hard days fighting the winds here in ole Texas trying to get a new metal roof done, watching this video while having a cold one, was a breath of fresh air (indoors of course). If any can find or fix it, you are the man :-). I have figured it out, "Iam to old an broken dw to be a good labor, but still an operator on a tractor with shop made forks.....hehe! See ya on part two for sure. Our Sammie knows you will figure it out, and be like new! Bear.

[@Rustinox]

Thanks Bear. Stay safe.

[@donaldsherman7905]

I love your style and videos!

[@Rustinox]

Thanks Donald.

[@brucewilliams6292]

Hi Rusty, Thanks for making this video. There are so many of us with less than great lathes it will be interesting to see how this comes out. Keep up the great videos!

[@Rustinox]

Thanks Bruce. I'll show it in the next video.

[@wizrom3046]

If you put it on your Deckel tilt table, you can tilt it at 45 degrees and cut one side of the v groove with your same fly cutter. Then tilt it the other way 45 degrees and cut the other side of the v groove. Then cut the other flat side again. Considering how bad the bow problem is, you should be able to dial in those 3 cuts MANY times better than the current error...

[@Rustinox]

That will be a lot of setup work. I just made id straight with sand paper.

[@melgross]

The “v” is usually 60 degree included angle.

[@1873Winchester]

Using the shaper might also work, if it has enough stroke.

[@Rustinox]

@@1873Winchester The shaper would be the best option to do this, but the stroke is only 220mm and the part 350mm.

[@1873Winchester]

@@Rustinox I do believe my first option anyway would have been scraping it, I would have scraped the middle slightly low instead of perfectly flat. Then as it wears, it will wear into full contact before wearing convex again. That's how Deckel scraped certain items like the gibs on the X-axis table as well, slightly hollow in the middle.

[@ED_T]

Nice to follow along with your thought process. I’m afraid that this problem of the bowed V-way is typically solved by scraping 😉

[@Rustinox]

Yep, I think so too...

[@MickZakrzewski]

Hi. I have a very cheap & nasty Chinese mini lathe which had a similar problem. I ended up scraping the saddle into the bed uding a ground up flat needle file and engineers blue (micrometer paste). It was tedious, but worked.

[@Rustinox]

Glad it worked.

[@JourneymanRandy]

That is important to repair. You will figure it out Michel. You always do. Nice work.

[@Rustinox]

I figured it out :) It will be in next video.

[@neilgarrad4931]

Thanks. Much to think about...

[@Rustinox]

Thant's part of the fun.

[@grahameblankley3813]

Very interesting video 👍🇬🇧

[@Rustinox]

Thanks.

[@daveharriman2756]

Hi Rusti, I always look forward to your latest videos, this bow you have on the vee ways can be machined on your Deckel mill, or if this was me I would use a straight edge with marking blue, and scrape the vees untill you get the bow out, taking care to scrape equally both sides of the vees. But I know you don't like hand scraping! but it is really not much of a job, if you weren't so far away, I would gladly help, cheers and take care Dave UK.

[@Rustinox]

Thanks Dave. I already fixed it. It will be in next video.

[@daveharriman2756]

@@Rustinox thats great!

[@catherineharris4746]

Man I'd absolutely love to have a big lathe like that one! Nice!👍👍👍

[@Rustinox]

One day you'll find one. I'm sure.

[@zedostenso3069]

Generally speaking the saddle ways are relieved in the center portion about ¹/3 of the total length of the saddle on the V and flat, makes so the saddle does not rock as the saddle wears. So basically you are working on 4 pads. As the saddle wears Generally on the front ways from carrying the heavy load from the tool pressure. Make sure to get the twist out of the bed first. If it's good proceed with checking the saddle you should start with the compound a work you way down to saddle ways. The easy way for you now is MOGLICE to bring everything back into alignment. Cheers

[@Rustinox]

Thanks for you input. In the meanwhile I fixed the problem. It will be in next video.

[@igorbucharev4831]

thank you for the video. I have the same problem with my machine, I will watch the continuation.😊

[@Rustinox]

It will be in next video.

[@howardosborne8647]

Hi,Michel. The cause of that warp/twist in the casting is most likely because the saddle has not been fully aged by heat treatment before it was machined at the factory. Any iron castings that are not fully settled/stress relieved by heat treatment will continue to move and warp for some time after they are first machined. Looking at the rock in that saddle also leads me to think it has been a big part of your problems with chattering when parting off. I see from comments further down you have resolved the problem now so I look forward to next week's video.

[@Rustinox]

I also think, the parting problems I have comes from the rocking and twist problem.

[@MatthewTinker-au-pont-blanc]

Re-scrape the inside of the "V" to take out the "bow" it won't take much!if it's carrying on one part of the "V" near the middle, the ends are not supported, leaving a gap which will allow it to twist a small amount! get yourself some Prussian blue to test it! It won't take much to scrape it! Cheers, Matthew

[@Rustinox]

I used sand paper. This cast iron is very soft, so easy to work.

[@MatthewTinker-au-pont-blanc]

@@Rustinox Your choice! Scraping is a far better result! I've rebuilt machines and scraped them in! Scraping is daunting, but my personal experience has been that it can be surprisingly satisfying ! Cheers Matthew

[@stewartfrye]

Murphy has moved from my shop to yours, I'm glad to see him go. Lets see how you get along with him. LOTS OF SCRAPING

[@Rustinox]

Keep the door well closed. Maybe he wants to come back :)

[@ydonl]

I enjoy watching you think about the problem and how you might solve it. I think that's great! I also wonder sometimes about your dislike of scraping. I would not want to try to change your brain, but when I watch people scraping, it's like they're saying to their machine, "I love you! I love you! I love you! I will invest the effort, and you will be perfect!". And then if they do not scrape, they don't say that, and their machine might say "Well... I don't love you, either!" 🙂 So that makes it more fun for me to watch you fix things without scraping... I wonder... "How is he going to do it?" You have to be clever, to think about it, as you said! Brains are fun things.

[@Rustinox]

That's a very interesting way to look at it :)

[@NellsMechanicalManCave]

Had a similar problem with my 81 year old lathe Michel. I put a short length of sand paper on the bed V using double sided tape and slide the saddle back and fore only on the high area. Remarked with a sharpie and checked it on an area of the bed. Then repeated until it was close to perfect. It's not quick, but it is cheap.

[@Rustinox]

That's more or less what I did. And it works. It will be in next video.

[@Man-in-da-shed]

“ I hate handscraping. Nuff said,

[@Rustinox]

Ind it's truth.

[@4SafetyTraining]

This is going to teach us some thing, Thanks

[@Rustinox]

Who knows? We'll see...

[@graedonmunro1793]

i enjoyed your vid!!😀😀

[@Rustinox]

Glad you did :) Thanks.

[@bulletproofpepper2]

Thanks for the update. I have rocking in my saddle also. I think it’s a poorly made gib. I am very curious to see how you fix it. The sharpie test is a great start. Thanks for sharing.

[@Rustinox]

I fixed it with sandpaper.

[@LetsRogerThat]

I wish I was there to help you Michel. It was great to see that the screw jack was useful. As I sit here watching your video and saw the saddle higher in the middle, perhaps what we’re seeing is that both ends have worn down a bit. That would explain part of the side to side rocking. There is a substance called “Turcite” that can be glued on sort of like a tape. And is can be scraped and is made for sliding surfaces. If anything can solve the issue that would be it. Of course you’ll have to scrape the high spot to level the surface but it may be the only way to bring the saddle back to original height. Just a thought. Gilles

[@Rustinox]

Thanks Gilles. I used you jack several times. It works great.

[@TrPrecisionMachining]

good video rustinox

[@Rustinox]

Thanks.

[@HaxbyShed]

That was very interesting Michel. I saw Vintage Machinery (Keith Rucker) remachine the v-ways in the saddle but he had a mill where the head could tilt backwards. He pointed out the bed is sometimes induction hardened but the saddle is not so in that way the saddle is designed to wear before the bed. I'll be interested to see how you tackle it. Cheers

[@Rustinox]

It will be in the next video.

[@MyMiniHomeWorkshop]

Perplexing problem to solve, but I'm sure you will get on top of it. 👍

[@Rustinox]

It's done :) It will be in next video.

[@MyMiniHomeWorkshop]

@@Rustinox I knew you'd get it 👍 I'm currently battling with a 5 kg lump of Cast Iron and I think it's winning

[@ianbertenshaw4350]

Careful Michel - There is a big rabbit hole right in front of you and you don't want to fall into it 🤣

[@Rustinox]

I know there is. That's why I take my time to think a bit.

[@edsmachine93]

Looks like you figured out the problem. I think that you can scrap this in. Thanks for sharing. Take care.

[@doug3458]

Scrape?

[@Rustinox]

I used sand paper. Worked just fine.

[@doug3458]

Good to know, I'm not really into scraping either.

[@RRINTHESHOP]

I think you will get it fixed, one step at a time.

[@Rustinox]

Thanks. In the meanwhile, it is fixed.

[@Lesfac]

Without the use of a surface grinder I think I would use fine emery paper wrapped around a former that fits the vee groove. With careful use and checking with the Sharpie method I think it should be possible to make a big improvement, even if not perfection.

[@Rustinox]

That is exactly what I did. It worked out very well. It will be in next video.

[@jonsworkshop]

Hi Rusti, I think you have found the root cause, and now you know what it is, I am 100% sure you will fix it! Cheers, Jon

[@Rustinox]

Thanks Jon. It's already fixed. It will be in next video.

[@MrFactotum]

eyup Michel well thought out, and i'm sure you will improve it further with a little thought, trouble is with any machine they get worn unevenly depending what they are used for, so you may not get it perfect, but much better. ATB Kev

[@Rustinox]

I fixed it. And it works.

[@stevewilliams2498]

Rusty. It is a good job the "Vee" way needs adjusting. You were making a mistake only doing one side. Removing the surface on the flat section will make the saddle sit wrong on the Vee. It will also make the cross slide lower at the back changing the centre height as the tool travels.

[@Rustinox]

I dressed the little error with sand paper.

[@harlech2]

Good luck, Michel.

[@Rustinox]

Thanks Nick.

[@dreamsteam8272]

Nice Video.... I always hate to adjust my lathe.... it takes hours and the result is ok... but not perfect... 😅 i think i'll never get a perfect result..... Stay healthy Michel !

[@Rustinox]

Good enough will do :)

[@melgross]

The rear clamp should never touch the back of the bed rail, just the bottom. I’m not sure if you were saying earlier that it was. Only on flat beds without “V” rails are there side guides. It’s hard to figure out why the dovetail is curved. I’ve seen a curve vertically in old saddles that match wear in the bed which had the bed ends curved upwards, in opposition, but never sideways.

[@Rustinox]

The last time I installed the clamp, it wasn't touching the side of the bed. And now it doesn't either. And indeed, it shouldn't. I managed to get the twist out of the saddle with sand paper. It will be in next video.

[@Gottenhimfella]

@@Rustinox I had the same thought. It is the the 45 degree surfaces of the front upstanding prism of the bedways which prevent carriage twist in the horizontal plane, but they can only do this if the FRONT keepers (that hook under the front of the bed) are free of clearance beyond the minimum needed to allow the carriage to travel along the bed.

[@Gottenhimfella]

Otherwise the push-off forces on the tool can cause the carriage to ride up the inside prism until the front keeper stops it. Especially at the tailstock end, where there is no downforce from cutting.

[@davidberlanny3308]

Hi Michel, looks a difficult one to diagnose and rectify. One thing comes to mind was Emma showing us round a friend's workshop where he was doing courses on scraping and overhauling machines, I wonder if he could provide some input. One way or the other you will improve it. Have a great weekend and good luck from Spain!! PS This week I came across a steam engine outside the RENFE workshops in Granada hidden out of view and a bit neglected. It turns out that it was built in 1904 by Ateliers de Tubize in Belgium.

[@Rustinox]

Nice, a Belgian tuf tuf machine :)

[@howder1951]

Lots of work to get your head wrapped around the problem, just have to devise more ways of measuring I suppose. This is what scares me a bit about my equipment, but I should really put the oils grooves in mine, as it was recommended to use grease and I want to convert to oil. Enjoyed, cheers!

[@Rustinox]

If you don't have the tools to do it, use your imagination :)

[@joell439]

👍👍👍👍👍

[@Rustinox]

Thanks.

[@JamesP_TheShedShop]

Love that shaper. Perfect size. On you lathe ? Are the ways break away at the chuck? Great video. Thank you

[@Rustinox]

Tha ways are more or less OK.

[@nobbysworkshop]

That's a real problem you have there Michel. I wish I had the experience to help. I hope someone in the comments can offer a solution. Sure you will get there in the end. Cheers Nobby

[@Rustinox]

Thanks Nobby. It's already fixed. It will be in next video.

[@nobbysworkshop]

@@Rustinox That's great news Michel. I'm pleased for you. Looking forward to the next video. Cheers Nobby

[@kolbroshop884]

its good educational video, but if i were in your place i would start from the bed. Check the bed for twist and wear. Then i would go on the bow in the saddle...

[@Rustinox]

I don't have the right tools to check the bed. But it looks OK.

[@markedevold1261]

👍

[@Rustinox]

:-)

[@stevengehm1287]

😊

[@Rustinox]

:-)

[@Steviegtr52]

MM funny one. I do hope you get it sorted out Michel. Can the rear heel have a vertical shim to stop the axial rocking. Regards. Steve.

[@Rustinox]

Thanks Steve. I'ts fixed :)

[@kimber1958]

hey Michelle Looks like there might be some good ideas in the comments to solve your problems good luck with it brother Hope you get fixed to your satisfaction

[@Rustinox]

Well, itis fixed.

[@brucematthews6417]

Your last finding of some "hourglass" like wear in the V way of the saddle is almost certainly the issue. I'd say that you need to scrape the V of the saddle to restore the riding points out at the ends to stop the pivoting. But I know you said you hate scraping. So I'll suggest that you use your "multi tooth scraper", otherwise known as a file, to do much the same to the V way as you did on the flat at the back. I don't have a proper scraper. So on occasion I've resorted to a file to "scrape" an area down in the same way as you. And it works very nicely. So I'm all in favor of setting up the saddle at a 45 each way so you can work "flat" to the surfaces and ease the high spots until you find that the V is riding at the outer ends of the "feet". You're removing metal at roughly the same rate. Just with a different tool. And with the felt marker to work with it can be done with very nice sensitivity to amount and "close enough" spotting. I hate to say it but you milled the back flat way to be parallel to the cross slide dovetail. And it was tippy. I'll bet it was tippy due to the wear on the V way. But you fit the rear flat way to match the worn V way. So you're back to the dovetail of the cross slide being at some slight angle to the bed ways. If you work the V of the saddle down to match be sure you check the dovetail to ensure it stays square to the bed. You're playing with the risk that it might end up with slightly concave or convex cone faces if not done with care. Ideally a big facing cut is supposed to be very slightly concave. VERY slightly. We see this if we polish a face cut on the lathe with fine abrasive on a surface plate. The outer rim polishes first and the middle last. But it is supposed to almost not be enough to see by any other means. Hope that helps!

[@Rustinox]

Thanks for your input, Bruce. I already fixed it. It will be in next video.

[@donisys]

Whetstones and patience on those v-bed ways my friend. Been there, done that and got the t-shirt. No fun at all.

[@Rustinox]

Indeed, no fun...

[@cyclebuster]

get the blue out and paint it all it has to have some wear issue. maybe some lapping compound and lap surfaces together?

[@Rustinox]

That sounds scary. I don't want to touch the bed.

[@cyclebuster]

@@Rustinox I know, but it works great for valves and hydraulic bodies etc.

[@paulshouse524]

It sounds to me as if the V-channel is too large, or otherwise distorted. I can't imagine how you could get that motion any other way. Let me say though, the things I can't imagine about a machine tool could fill a vast area.

[@Rustinox]

Lol, thanks Paul.

[@russelldold4827]

I have suspected the prismatic slideway was "bell-mouthed" from problems shown in previous videos. I think a previous owner tried to fix it and either he or the person he entrusted to do the work distorted the carriage when they clamped it before machining. For me the solution lies in scraping, but since you claim you're allergic to the process I'll wait to see your solution.

[@Rustinox]

Too high clamping forces. That makes sense.

[@frank77154]

If you want, you can borrow my biax powerscraper and some straight edges. I think I don't live to far from you. Greetings

[@Rustinox]

That's a very generous offer, Frank. Thank you very much, but no need. I already fixed it with... sand paper. And it works just fine now.

[@MrWreeve]

I foresee some scraping in your future.

[@therealspixycat]

You can also clock the V grove of the saddle? To get an idea if that is the problem?

[@Rustinox]

Indeed, but I don't have the right tools to do that.

[@therealspixycat]

@@Rustinox what do you need in terms of tools? Put a magnet of the indicator on the cast of the machine?

[@JeremyMakesThings]

Wait, you mean the saddle isn’t supposed to twist back and forth on my lathe? 😂 No one likes scraping, but you have to do what you have to do. I’d say get some blue, blue up the ways, and get a real good idea where the saddle is contacting they ways.

[@Rustinox]

Thanks Jeremy. It's already fixed. It will be in next video.

[@sidetrackmetalworks2058]

How do you eat an elephant? One bite at a time! Good luck with your elephant Michel. Chasing inaccuracies can get frustrating, especially when all you want to do is make chips!

[@Rustinox]

You're right. One by one.

[@billshiff2060]

So what is the final result here?

[@Rustinox]

Much better, but still not perfect.

[@taranson3057]

I think your lathe bed is twisted. Maybe you will need to shim the lathe bed feet to remove the twist

[@Rustinox]

For what I can measure, there's no twist in the bed.

[@taranson3057]

@@Rustinox there are precision machinist levels that are used to do the checking. A very minor twist of the lathe bed will show up in the finish and cause grey hair, hair falling out, colorful metaphors being screamed out and so on and so forth. There’s a good bit of KZbin video on how to check the lathe bed for a twist.

[@richardjones-sl2zd]

Funny how the indicator's movement doesn't seem to be quite in sync with you moving the carriage; as if it has a life of its own. But whatever, I expect you'll get to the root cause soon enough, even if its annulment might be a step harder. Happy hunting.

[@Rustinox]

The indicater was installed in the part with a wave in the surface. But indeed, it's not constant.

[@rafirafilandzki8354]

sorry byt I don't understand very well, you touch the dial indicator to the lathe bed in a place that is not used to move the carriage. How sure are you that this plane is well machined and parallel? Regards

[@Rustinox]

We're never sure of nothing. But that surface is nicely machined.