Part 1: Teardown We are replacing the damaged spindle bearings on our JET GH-1340W, 13x40 gearhead metal lathe. While we perform the repair, we will also replace all ball bearings.
Wow, you sure are brave. My 13X40 Jet Lathe is now 15 years old. So far it has held up well, it is very accurate and no problems with the bearings. The inside of the head does not look a nice as yours, but no chips or junk. I've changed the oil several times little or no grit in the oil. Can't wait to see how you put it all back together.
Hello Yuchol, your Videos are just great ! As mentioned before, the outer Bearing shoud be a tight slip fit on the Spindle, but it never is on import Lathes. But its easy to correct with a Lapping Ring made from Aluminium and some abrasive compound. You could place some wick in the oil feed holes of the Bearings, this would prevent any particles from getting in. The restriction in the flow is no Problem, tapered roller bearings dont need a huge oil flow. They run cooler if they dont need to displace a lot of oil. Some fine wire mesh, like on an oil burner Nozzle (not the sintered stuff) could also be used. Greetings from Germany !
Wow! I'll even say it backwards woW! That is a shot in the pocket book after buying that lathe. Thanks for showing your method behind the madness on replacing the bearing. Good luck! Looking forward to the next one.
Makes me wonder if I should open mine up too. Great video Yuchol. I now see that you aren’t afraid to tackle any job thrown at you. Can’t wait to see the second part.
Great video, Yuchol. When you put the headstock back together, might be a good idea to attach a magnet to the drain plug to catch any filings as the gears wear normally.
more than 1 magnet would work in different locations. they won't dislodge from the case if put in the correct places, and will prevent future damage. Nice work. I probably would have taken the handle gears out.. you are already 99 percent there. So little work, and you are waiting.
Wow! Great job Yuchol! Can't wait for part 2, maybe 3. That's a lot of work. Guess we'd be better off if they just sent us a box of parts and we could clean up and assemble them our selves. That would cut the cost even more. Keep the great videos coming. Stay safe.
Yuchol, this video has been a huge help to me. Thank you! After recently purchasing a Victor 13x40 a few issues have been found. One was that after running for a few minutes the chuck end of the spindle was puking oil. Seeing how the headstock is assembled was a huge help. Mine isn't identical but it's close enough that there were no surprises when I opened it up. I have a heat gun identical to yours and it worked great with a little patience. The primary reasons for oil running out of the headstock appear to be overfilling and a bad gasket under the bearing cap. A cloudy sight glass didn't help matters. The rollers and races are no longer shiny but still smooth and runout inside the spindle with a dial test indicator was .0001-.0002 so I saw no point in replacing them immediately.
Nice job Yuchol, you are doing what should have been done at build. It is completely beyond me why companies put time into line boring castings for shafting, and then just leave burrs everywhere. The de-burr and clean would be less than one tenth of the machining time..... So sad that everything these days is made to a price point rather than a standard. You are bringing it back to life nicely, well done. Jon
Nice video. I am so happy to see a person who cares about his equipment. Your initiative and patience are obvious to me. Also takes courage to tear into a repair not knowing how much work it will involve to finish. Cleaning the headstock will bring years of trouble free service. Enjoyed watching you proceed with the repair and wish you success in reassembly. Thanks for sharing.
Thank you for the movie. Consider putting some big magnet (for example from old speaker) into headstock close to oil pump drop - naturally wearing stuff will not flow internally, but stick to magnet. It also gives better view about oil quality - small pieces will not be visible without optical zoom (at least 2$ small watchmakers x10 magnifier).
Hi Yuchol Watched your video again. Use to build big race engines about 25 years ago. In the heads where the oil returns back the the main block we epoxied some of those small rear earth magnets to catch and metal files also give a tell tail sign something was wearing out Just a thought. I would hate to go through this myself I have a couple in my old King machine which is also a Chinese made but I have had very good success with since 2004. I change oil about every 6 months and pull the main cover off to check those magnets for chips or filings. Keep up the good work. Cheers Fred
👍 thanks for sharing. These repair videos are the most valuable in my book. They're the rare ones. I'm in the process of cleaning up a Colchester before I put it in service. Sure hope I never have to go under the hood!
Gday Yuchol, it’s disheartening when you see this issue in machinery, a lack of quality control during in the factory, it’s a cost that could be very easily avoided, I’m really looking forward to seeing the shaper, nice addition to the shop, fun times ahead there mate, take care Matty
I don't think it is avoidable, wherever gear surfaces meet, a break-in procedure might be required. After transport, under load and depending on temperature the dimensions do change quite a bit, which means a break-in at the plant won't cover all of that. How much is acceptable depends, and how much burr those parts had when being assembled. This means with new bearings and freshly assembled a new break-in with oil change might be required - but that's usually done to estimate the preload of the bearings alone anyway.
lee I quite agree although the gears may well have contributed to the swarf in the headstock it's mainly as Yuchol has shown where the headstock openings were bored that has left swarf on the outer edge of the casting. Yuchol clearly shows pieces being broken off of the casting. Failure to deburr during manufacturing by the Chinese factory is the complete cause of this problem
I am learning that setting the proper bearing load is more of an art than science and the preferred method is to look for a temperature rise at the bearings rather than using torque measurement
Ouch. Surprising how little care was taken in putting that together at the factory. If it was 80 years ago I reckon there would have been actual people inspecting it before going to assembly. I guess that's what the paint is for lol. Thanks for the share, Yuchol 😊.
Yuchal, that's Tuff Stuff... I hope the people from Jet Company are watching. That's terrible quality control you should have never had to go through this. Thanks for sharing!
Great video. There's something deeply satisfying about upgrading sub-standard machines. You just know that your lathe is going to feel, sound & cut much better than previously. It'll make you feel good every time you use it. If that's not good enough there's the bonus of having to buy quality tools. The other tab I have open is the Knipex catalogue :-) Looking forward to part two. It was rhetorical your question about the shaper restoration...right?
Greetings, just replaced the countershaft bearings on my lathe, similar to yours and a lot of debris from the failed bearings but luckily the spindle bearings seem ok. Mr Pete is 100% correct, I also had machining chips that had migrated through the chuck end Labrinth Seal, the chips CAN go into the gearbox even without using compressed air. I have placed a large magnet in the gearbox and regularly clean to remove debris, most of which comes from the non hardened gears. Looking forward to see you reassemble,
SKF Aktiebolaget Svenska Kullagerfabriken founded on 16 February 1907. Is a swedish company. S for Swedish, K for kullager (ball bearing) and F for factory. I know they produce all over the world but they are still Swedish ;-) I am very impressed with your approach to this repair!!
Good hunting for those bearings. I spent hours working to find precision bearings for my Boyar Schultz surface grinder spindle. Prices seem to have no upper limit - LOL. Well shot video. Anxious to see the rest of the series.
actually those are tapered roller bearings they will be pretty cheap and easy to find. boyar schultz and most higher precision spindles uses angular bearings which get pricey fast.
Great content, nice work and very informative. Your lathe will perform like new. The source information of the parts and prices was good also. I have a 12 x 36 Enco gear head lathe that I purchased new in 1987. I am thinking it needs the same service as your lathe did. Thanks alot, Ed M.
So it sounds like if you buy one of these machines (assuming mills are made to the same modest standards) either one rebuilds it the day that it arrives, or rebuilds it a year or two later. The major difference being that if you clean it up and deburr all of the internal parts on Day 1, one might ultimately be able to save the cost of replacing expensive bearings and gears. Thank you for this very informative and insightful video. I don't own a lathe and never will, but I think you have made a beautiful investigation into sources of failure. Beginning with the folly of assuming that just because an item has been manufactured to spec dimension it has therefore been made "right." Deburring, cleanliness, seals and lubricants being also and equally crucial for long-term success.
Thanks Josh. I bought this lathe because I’ve had the exact one 16 years ago and that was a good lathe. Unfortunately the first one was made in Taiwan where this one was made in China. The quality just isn’t what it was. There are other brands that I feel comfortable buying today, just not this brand anymore.
@@woodscreekworkshop9939 are these models still sold by anyone other than Jet, but still made in Taiwan? I used one about 22 years ago, but it had been abused in the electric motor shop and needed some work, I wanted to take it home and rebuild it because of the size and I thought it had potential for a home shop.
Great video man! When it comes to bearings, I’ll only use Japan or USA made. I was really surprised at what Jet was asking for a Chinese made bearing. I wonder what the markup is on that. I look forward to part two of this rebuild!
The mark up margins are enormous. Many hundreds of percentage profit. Rolling element bearings have always been a lucrative business. I had several years experience with a work colleague who was a main stockist for several well known bearing brands. The recommended prices are ridiculously over the top on some larger bearings.
I've bought bearings in china (popular auto /truck replacement sizes and was shocked how they were stored and handled. They have no sense of storing, packaging away from silica contamination. So now i pay a premium for japanese.
Some tips to NOT ruin those fine super precise new bearings and the other ones: -put the cups in the freezer to shrink them. -put the cones in your oven and heat them up, mind the temperature of course. I say max. 110-130 Celcius -check housing diameters; if fit is too loose, a bit of loctite works miracles :) And never ever!!!! hammer in a bearing!! might as mount the most crummy el cheapo bearings but mounted correctly! Turn some nylon rings that fit the rings precisely and use that soft mallet to drive them in; all to avoid shock. Better would be to use a press for the cones on the shafts. Brass rings maybe for the shaft mounted bearings (heat!) last tips: -check for markings on spindle bearings for top of run out; usually a dot is etched. Then make sure both bearings are positioned at same spot to avoid -work as clean as you would work on hydraulics -make sure the shoulders are spotless and square. -proper pre load specs for those tapered roller bearings, make sure to make 10 to 20 revolutions so each rolling element makes a full revolution then measure torque with unster. Good luck with the new quality bearings!
Great video. Yuchol. My 25 year old Sharp 1340 is very similar. I've changed oil a couple of times...never looked into it as you have. I need to do that.
Awesome video, great information. I’m sure my 12x36 gearhead lathe will be needing new bearings soon. The de-burring, cleaning, Japanese bearing, and the love in general is gonna make that lathe the machine it should have been when you purchased it. It’s too bad a man can’t purchase a lathe for $10k that wasn’t just thrown together and lasts longer than a couple of years. Jet should have given you the bearings for free. I’d rename the video something catchy like “Jet Lathe 1340 my $10k mistake and how I evened the score”.
It's a shame that you have to do this. It sould be a trouble free machine with the way you are going about repairs. Nice choices on the bearings and the tooling that you bought for the job. Great job on the way you presented everything in the video. Looking forward to the next video, hope you show going through some of the sub assemblys. Andy
Hey, great video. Well done on taking it on. On my colchester i added an in line oil filter meant for a tractor. It has a removable can with the filter and a mount with hose tails at the inlet and outlet. Very easy to mount between the oil pump and gearbox. Also, for cheap bearings, if you know anyone living in china, buying them on taobao is really cheap. Most sellers wont ship outside of china. But you can get all the big brands like skf nsk etc and high quality but they're about 10% of the price of in the uk. I have worked out there and stock up when i can. Thanks for the video!
Thanks for showing, I like the way you handling this open heart surgery operation. I know this is waiting for me along the line. Please let us know after you replaced all bearings and assembled , apart from the spindle bearing noise if the noise running at various speeds has noticebly changed. My gearhead lathe is quiet enough at low gears forward(No complain), a bit noisy for same gears in reverse. At higher speeds like 1800 it sounds scary to me, but not as scary as some racecars with straight cut grears. I did not had the oppertunity to hear a similar lathe 1st hand, so would really appreciate your take on the noises afterwards, thank you again.
Looking forward to Part 2, as I’m curious to the proper fitment of the outboard bearing to the spindle. I always thought it should be a slip-fit to allow proper preload adjustment. I have a cheap 10” Taiwanese lathe that has the same press-fit as yours had coming off, I think I should fix it. Anxiously waiting to learn from your experience!
Use felt to help filter the metal shavings out of the oil in the holes for the main bearings this will allow the oil to wick through the felt. search felt wick its quite common
This was quite interesting, as my 12x36 has some similarities to your 14x40. I had thought Jet would have had better cleaning and quality control, they have a decent name for themselves. My lathe is due for an oil change anyway, I think the lid will come off like after I first bought it and cleaned it, I'm wondering how much crap is floating in the transmission now!
Hi. One more useful tool would be a bearing separator. This comes in two halves which fit round a bearing and then bot together. It has near kife edges that will prise a bearing away from it's neighbour and it also allows long all thread to be used to pull the errant bearing off a long shaft. They are not expensive and well worth having. Probably still need the heat gun. Stay safe folks. BobUK.
I would like to have a lathe that has the old style v-belt system and instead have precision bearings and other equipment critical to accuracy at a affordable price.
Very interesting and informative video. I'm a new subscriber (today) and really like the thoroughness and clarity of both you video and your narration. Excellent work! I really admire folks who just press ahead when faced with challenges such as the ones you've faced getting, and keeping, this lathe in good running order. Good job sourcing those bearings, standard replacement parts charges are such a rip-off. Jet should be ashamed both of the quality of the machining cleanup during manufacture and of trying to make their standard item spare parts a profit source. Good on you for proving how that will backfire. You got better bearing for a fraction of their asking price. My only slight disappointment was that you didn't show us the comparison of the worn old bearings with the brand new ones. Guess I'll have to be sure to tune in for Part 2. Wait a minute, was that a subtle cliff hanger?? Well intentional or not, I think it will work.
Those bearings would have been installed by heating them to a temperature of approximately 250 degrees farenheit so they would slip into the spindle shaft. Don't directly apply heat to the bearings nor hammer them
Great content. I have a kent kls1340a which is very similar I've also have seen similar defects like yours like leaking all over the floor thought about a drip pan like yours didn't have one so i just put gasket maker around the tray and pedestal now oil drippings just flow into chip pan which i also have to redo some of their welds on pan brackets this machine is only 4 years old and not ad much use as yours but the problem appears to be the fact that they have no pride in their workmanship any more. I thought abou selling my original smaller craftex combo lathe mill but decided to keep it because wont get much for it and I've had to use it to make parts for my other lathe and mills when they break down like when you had to make new detent collar but you can't do it if lathe doesn't work at least it wasn't a critical part that machine won't work while making new one. Word of caution for the lid If you don't use a gasket just sealer that rib on lid needs to have notches cut into to allow oil into the trough for oiling the bearings I reused the gasket but lid was bowed so i notched lid for oil flow a used gasket maker on both sides of the gasket this also cured the major part of my oil leak Good luck with getting it back together and getting it going
You need to loosen the fit of the outer end spindle bearing on the spindle or you will not be able to set the pre load properly! It should be a tight sliding fit. If it binds up as you adjust the preload the main bearing behind the chuck will still be too loose. Phil UK
thanks for the video! Really helps since I will have to do the same thing soon to my lathe soon. Could you add to the description some details on what tools you are using? I don't have a pencil and paper anywhere near by and have too many gray hairs to remember all the details you just went thru. I am always worried about getting sub-standard tools for a quality price. Since you seem to know what you are looking for, the less informed of us (ie me) would really appreciated the info!
I wonder if all of the crud/chips/dirt was in it when you bought the lath from when it was manufactured? I've seen other videos of people taking apart brand new lath chucks and indexing heads. They were full of grit from the factory. Maybe it would of been a good idea to cleaned it out when you first bought it.
Some of the ones I’ve pulled apart have had pipe cleaners shoved down the oil holes. Form into a V, shoved down the hole, then bend flat what’s sticking out to stop it going all the way in. Will definitely stop big chunks of grit.
It's amazing how poor the workmanship was on the inside of the headstock. I bet those chips you found are from the original shoddy workmanship. Big project. I look forward to seeing the rest.
Did you buy this mill new? If so, I would have been HOWLING mad! That's inexcusable workmanship, even from a mainland Chinese produce product. I am looking to buy some shop equipment in the future, and I am struggling with the brand. I think Jet just knocked themselves off the list. BTW - Shop Doggo best Doggo!
I ordered new Timken bearings for my Bolton lathe a few months ago and they are just sitting on my workbench because of the dread of installing them, although I read it makes a world of difference to get rid of the Chinese bearings that's in it now.
Yes, I would feel the same. On the other hand seeing this video and also a whole series from a channel called Swan Valley Machine Shop does provide lots of useful illustrations and tips and tricks for getting the job done. The SVMS videos show complete disassembly of a Taiwanese 12 x 36 lathe (different source, but basically identical to the PM-1236T). That combined with this excellent WCW series will be excellent inspiration for getting these jobs done!
@@woodscreekworkshop9939 Well, my motor burned up on my lathe so I had to do quite a bit of disassembly to dislodge it from where its buried in the back and I took the opportunity to replace the spindle bearings. Wasn't as bad as I thought it would be. Thank you for the motivation!
Dang, Yuchol that sucks, those bearing would have lasted 20 years if the manufacture had a little pride and detail in there workmanship. It's going to be better than new when your finished....enjoyed the video
Big job and big expense. Sort of gives me some happy feelings about my simple old Craftsman lathe. Some of the machine companies price things at ridiculous levels. Sort of like car dealers price repairs. I will be back for the next part.
Very good video how long did it take to get that bad and how much use. Was it run very frequently for several years or less? Also did you have much runout because of the bearings?
I’ve had the late and used it “frequently” for a home hobbyist, the runout was really low. Other than the noise, I had no complaints of the machined parts. I am certain the runout would have gotten worse if I kept using it.
I think the bearings are all made on the same manufacturing procedure and graded accordingly to run out and the p5 tolerance is stamped on the bearing which you pay an arm and leg for.
The production lines for the lower class bearings are not set up to take the all the measurements needed for the higher precision bearings. Precision bearings are usually made on separate lines since they get much more hand fitting and measurements taken. If the rings or rolling elements do not meet the tolerances, they are reground until it is within them. They cost so much more because the labor to make them is significantly higher.
@@mikeb1520 Damn right you are, I used to sell bearings and had an engineer over for super precision spindle bearings problems with an OEM machining center customer. Long story short; all bearings of the run out quality needed be ABEC 3, 5 and 7 are made in specialised produstion lines or plants. The amount of inspections and measurings make these type of super precision bearings so expensive. The most expensive ones are made in sets that are marked not just with top of run out (etched dot), but are sorted and marked with an etched V mark across the set to avoid mixing the bearing set up Guess what; that OEM customer had some apprentice mixing up a set of 4 angular contact bearings, no wonder they had troubles.
ervie60 I used to work for FAG Bearings in the Barden Bearings building, Barden only made ABEC 7 and 9 bearings, these P5 bearings in the video are scrap to them :). The ABEC 9 bearings had their own temperature controlled room with dedicated grinding, honing and measurement equipment, as well as employees. The people making ABEC 9 bearings only made that class bearing. After seeing the work that goes into making bearings of that quality, the prices don’t seem so outrageous.
@@woodscreekworkshop9939 Yeah, sure will do. I'm just going to fix do a job or two on the lathe first. I've got plans to redo the bearings in the mill, and I want at least ONE of my two machines to work, in case I have to "fix" something.
neodymium magnets stuck down in the corners of the headstock.. will pull all the steel and iron particles out of the oil.. Do you have a CO2 only fire extinguisher... that you could discharge down the spindle tube to shrink it to allow the bearings to be slid on easily.. or pickup a 5 dollar pack of dry ice from the local ice supply or wholesale grocer. you may want to stop at a parts store and pickup a tube on a card of permatex 85420.. inside the tube is Permatex. you can spread that out really thinly. to seal the cover on.. Please spend the hour and Blue up the top cover mounting flange and see how much contact you have with the top of the headstock case.. before installing anything.. please measure the holes that are the drip oil feed to the spindle bearings.. take the measurement and go over to a transmission parts supplier or sometimes just a automatic transmission shop and see if they have some cone shaped filters to put in the holes.
I bet it is going to feel great to have new high quality bearings in your lathe. I have a 50 year old Colchester with the Gamet bearings. If it ain't broke, don't fix it, in my case. I think when some lathes need spindle bearings, it's time for the scrap yard. If you had to pay over $2,000 to replace bearings in your lathe would you do it? Or look for a new one? I had a 13" South Bend lathe that was made in 1941. The cast iron bearings were in new condition. Maybe those guys knew a thing or two about quality. Of course the max RPM wasn't 2,000+
I was repairing my milling machine spindle today, it is 100 years old, It runs smooth now, but the taper has a 16um runout (7 tenths), not very good, I am sad
It's a shame that alot of the final handwork is skipped. I guess these companies are trying to come in at a price point. I imagine that most customers would be happy to pay for a couple more hours of labor considering the difference it would make.
Dear brother I designed a 12 speed lathe Headstock by watching your both bearing replacement videos but it's not working properly I think lot of points are missed due to the fast videos could you please upload the original full video with normal play back so that I could come out of the problem in which I am badly stuck. Please do give me some solution otherwise my job will be in danger I designed it for a company in which I am working with.
Hi Yuchol I've a Taiwanese Dar Sin 1230 Geared Head Lathe ( Sold by Frejoth (Acra)). I imported myself 1982. I shall renew the spindle bearings in near future. It might be vise to renew all the bearings and clean thew whole headstock. Did you take any video of disassembling, and assembling the gear shafts, gears and bearings?
Careful, OEM's often order with a specific tolerance on precision and unless you know what it is you may not be getting what you need. Even from a reputable bearing supplier those prices seem to good to be true.
Good work cleaning that up I had the same issue of stupid tight bearings with my mill spindle a while back. I suppose it's better than loose PS at 0:51 it looks like you dropped your lathe dog on the floor :P
Wow, that should never happen on a new machine. I guess the people saying you need to flush the grit out of these brand new are right. Makes you wonder if you need to redo the rest of the machine as well.
