Monarch 16" Lathe Restoration: Feed Rod Bushings and Worm Gear
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- Опубліковано 9 лип 2024
- While restoring the apron on my Monarch 16" Model K metal lathe, I discovered that the bushings that guided the feed rod were worn and needed to be replaced. The old bushings were knocked out and the bronze bushings pressed out. New bronze bushings were machined on the metal lathe using an adjustable mandrel turned between centers and pressed back in place. We also installed the half nuts for threading on the lathe as well as the worm and worm gear.
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I agree with Brian Block. Having the ability to get service this day in age is valuable.
Love your channel Keith, not just the channel, but the comments as well. Life happens outside the shop, thanks for posting every week.
Glad to see the further adventures of the Monarch Lathe. Hope the storm this weekend misses you.
Boy Keith, you could not have posted this vid at a better time. Just picked up a Pratt and Whitney Model C, and it has some issues in the apron, now i have a bit more insight to what i will be getting into.
Exactly the same issue on my DSG 13/30. Worm and worm gear shot. Replacement price for the worm gear alone £900. Made a new worm on the lathe and extra length to make a hob cutter. Roughed our the worm gear with an indexing head on the mill and then used horizontal mill with the hob cutter to finish the hob driven gear.
Nothing like a fresh apron. Thanks for sharing the work.
I tried to get some bushings for the concrete mixer locally, nobody had them. I even checked the Motion Industries branch in Riverside, and Grainger. Motion would have had to have them shipped from Chicago, Grainger from Denver. I ended up buying three pilot bushings for a Chevy S10 and machined those to the size I needed. We lost a great resource when the local, old timey hardware store in the area closed up, and another when Mr. Hahn retired and sold his machine shop, that building now sits idle. All the other old style shops in the county dried up as well. Torch and grinder operations are about all that's left.
No new folks to take up the old ways. Same here. All the old standby shops are gone and dried up. And 10/4 on all the junk in the air. Whoever said the allergies got a break in winter, LIED!
I did my Apprenticeship on a Colchester Lathe at the maintenance workshops at the CRB country roads board Victoria Australia and had to deal with Imperial and metric as well as the thread differences of AF, Whitworth and metric
I was told by a machinist that the bushings were Meehanite casting. Hope that helps Keith.
I saw the comment about the bronze gear in the last video and totally agreed. Still, doesn’t make it easier on the bank balance but you just have to bite the bullet sometimes. Interesting episode, it’s sure to be a worthwhile investment. Regards.
Yes, it's the old story of 1 hand washing the other. Sadly, too many folks are in me, me, and only me mode. :>((
Eli D.
Envious of the equipment and the stuff you work on, but mostly envious of the s p a c e you have. It must be great to have that to accommodate the temporary and permanet aquisitions
Will be doing the same thing to my Series 60. Great to have a guide for the journey.
As always, an excellent presentation and I learn something every time you grace us with your knowledge and common sense. Keep up the good work.
Superb work Keith. You have no fear!!!
Thank you Mr Keith Rucker!
I always console myself when I need to buy a expensive part from a OEM company by telling myself that I am just one person and they have a entire staff working to help me. I find great comfort in that. If not for their effort in the long term I would have to use a different company and in today's world where many of the old companies are no longer around, supporting them is the right thing to do.
Good job, Keith. Getting closer to done!
GREAT JOB. YOU WILL HAVE A NEW MACHINE WHEN YOU GET DONE. THANKS FOR SHARING KEITH.
Looks like it is ready to go. Nice job.
thanks for the update Keith
Great work can’t wait to hear this baby humming. Looks like you won’t be regretting not going all the way on anything needed.
Nice job Keith.
Very good.. Couple things to note.. If you look at the product detail for the McMaster bearings they are sized 2 to 3 thou over so you can set the press fit.. I'd add a chamber to the drive rod slot to keep it from cutting into the bushing. It likely don't take much but my bet it that the chamfer is gone where the rod is worn.
The power of persuasion and guts. Masterfully done once again Mr. Rucker. What ever did you do without that shop?
great job Keith , Enjoyed ! Thumbs up..
Thanks for the video Keith.
Hi Keith,
Nice progress on refurbishing the lathe. Looking good.
As a Patreon supporter of your channel, I just want to say that I agree 100% with your decision to buy that new gear, for all the reasons you mentioned. I'm more than happy to have my donation go for something like that.
Looking forward to the next episode.
Joe
i guess you patreon guys paid for that gear this month!
A pleasure to watch you work your "magic"
Very enjoyable and educational. Thanks!
Keith! So many times I wish there were a way to just give ya a helping hand. Let us know when you'll take apprentice and similar. I'm in the welding side of steel work and engineering...and know jack about machining!
Thank you again for these videos!
THANK YOU...for sharing.
I like this series.
The bronze bushings for the feed rod were definitely a repair at some time. Its been a few years, but I think that on mine, it was a solid cast iron bushing that I bored out and put bronze bushings in.
I certainly understand throwing a bone to these long time companys but wow that sounded like part of the whole cow. And yes I have done the same in my electronics world. We all do it keeps the long term companies in business. Thanks for sharing this has been fun to watch. I am not a machinist but watching your stuff and a few of the others like Abom79 and Keith Fenner , it makes me want to try to take up the machine trade. Thanks for inspiration...Vic
thank you keith
I would love to have a press like that, one of the shops I worked in had one. Since then, I haven't used one that even in it's class.
You could use the old brass gear as material for making a smaller gear or for a bushing.
Enjoyed Keith!
ATB, Robin
Good job.
Thank you for video.
You are making great teaching with this channel:) 9:24 instead of expendable mandrel one can use hard, dry wood (for example oak). After soaking up, wood produces quite big pressure to hold bush in place. Metal ending could be necessary for turning between centers. Mandrels, or toleranced rods are better, but it is easily applicable as well and more flexible in usage.
Wonder if it would help to leave those bushings long and simply sticking out of the end of the housing? would greatly add to the effective contact area and extend wear. I would've also considered taking a flap wheel to the edge of the key cut into the rod and break the edge of it.
It is my hope that you and all of your viewers are able to watch you repair the 16" monarch lathe when you have it worn out again.
love the vids!
gracias,maestro de maestros!
It wouldn't be stock, but what you might do is fabricate a pair of keyway fillers, little chunks of metal the size of a key but flush with the shaft, that then have some means of attaching to the worm gear and it's key, maybe a screw along the keyway threading into the worm gear's key, or partial overlap with the worm and a perpindicular screw; just something that would take up the keyway and reduce the cutting tooth effect. Also, if you could put a slight radius on the keyway, both with and without a filler piece that would reduce the cutting action by a lot.
Keith
I could not help but notice that on the lathe that you were turning the bushings on, you are missing a chip cover over your cross feed screw.
That could get ugly if you are ever machining some cast iron.
Very well done Keith. From the video, it looks like the worm driven gear is not centred above the shaft. Perhaps that comes later. I find taking a lot of photos during disassembly helps my memory........
Your socket set is a great source of things to use to press out bushings. Be sure to check your handle alignment before putting all the half nuts in place.
I was wondering about that myself. However, Keith doesn't tend to sweep goofs under the rug. He puts them into his videos to help other folks avoid them. (It was a 50/50 chance; it may just be that he lucked out. Or maybe he checked and just assumed we would all do the same.) If Monarch had assumed that their lathes were going to be renovated by non-factory people for the first time, they might have made it impossible to put together wrong by making the pins different sizes.
I'm kinda waiting to see if he lucks out on the handle alignment too- had he double checked, he probably would have responded to the original poster right away. I wonder if the factory had a jig for aligning the handle and drilling and reaming the tapered hole before assembly so all the parts would interchange or if they hand drilled and tapered the hole on each machine.
I think he cheated on the handle- in the last video, the handle is already in place and no mention of how it was installed.
Hi Keith , could I offer a little suggestion on press fit bushing , I noticed ever so slight missalignment on your first one and it scrapped some bronze from the very slight tilt as it pressed into the cast iron bush . Long time ago when I did work on toolroom jig borer we had the practice of relieving the top 1/16th of a bore out to the dead size ( rather than the interference size ) this had the effect of giving a guarantee of accurate alignment of the insert bush to be pressed in before pushing on it . Same principal will apply on the last 1/16th of the OD when making bush to have interference fit in an existing bore .
i think if I ever have to do this repair to my Monarch I will retrofit a couple of ball bearings to replace the bushings and let the set screws ride in the key way so that the shaft and the bearing bores don't wear and it would be a better design, looks like there is plenty of room for it.
Yeah, that seems to be the right way to go. And there's plenty of space for it. You could get those bearings that have flanges (UCFC205-16) on the shaft holder and put either a loose key that's tied in with a set screw, or just a set screw with the threads that would engage the shaft deleted.
Considering other components on their lathes, i'm kind of surprised that this is the solution they came up with...but that humongous size of cast iron bearing material, makes me suspect that it was initially planned with an actual ball bearing, otherwise, it doesn't really make sense. That's a huge lump of cast iron just to hold a simple rod...
Brian, you are very pragmatic (that's not an insult). Keith likes restorations. I mean, some guys think a '59 ford pickup with a big-block Chevy engine is great, some people would rather drink castor oil in their cocktails than bastardize a classic. :)
Perhaps a poor design, but the bronze bushings will probably outlast Keith don't you think? How quickly do they wear out?
Barry Gerbracht how often is the lathe used ?
But remember that the bearings slide along the shaft so something has to wear. If you use ball bearings they will be harder than the shaft and will wear it out, rather than sacrificial bronze or CI bearings
I must admit I winced a bit when you started beating on that feed rod and it didn't slide well to begin with. I thought; it's not supposed to go like that and then shoop! All good. Sometimes you just gotta resort to whacking em home. Nice job!
Went back to September 22nd and it is the same there
I assume why the right hand tapered pin was mushroomed is that someone didn't line up the bushing's mating surface and the guy just kept hammering the pin until the bushing was forced to rotate into place.
wow those were really egged out....Glad you were able to catch that before it became a bigger issue
i was thinking that some sort of ball bearings also.. but with the bronze bushings.. how about carving a groove for a wick that could allow oil from the sump to lube at least part way into the bushings .. perhaps put the wick groove in as a spiral.. so movement may promote oil flow around to the top wear section.
I just discovered your channel after seeing you in Abom79's latest SNS. Subscribing is a no-brainer!
The reason the bushings wore the way they did is because there's a misalignment between the rod and the carriage. A key would wear the bushing bigger not off center.
It is because of gravity, that long thin shaft hangs down from its own weight so the carriage is trying to support it and thus gravity tries to pull the shaft out the bottom.
07:45 Gives new meaning to fitting a square peg into a round hole. lol
Would it have helped during the final part where you were putting in the feed rod into the bushings plus the worm if the right hand bushing wasn't already installed?
Another great video, thank you sir. 2 questions from a non machinist but a mechanical minded gearhead. 1) Where there is (I assume) lube oil in that gearcase would it make sense to replace those bushings with bearings thus stopping the keyway from shaving the bushings? 2) What is that 5' long piece that looks like an aircraft wing inner support that sits on the top shelf behind you?
How on earth did you align the key inside the worm; " amazing top effort"
They are a well built machine.
You commented about the sharp edges on the keyway acting as scrapers to the inside of the bushes, would it be worthwhile to hone those edges to form a fine flat to take away that cutting edge?
Is it likely that oil will come out of the remaining holes from the roll pins from the saddle oiler?
It would have to be a maintenance item. The key is regularly being rubbed into one side of the slot or the other as it slides down the shaft. Eventually would work up an edge on the shaft.
Impact sockets make great pressing tools, Beware chrome sockets they can be brittle and bury a chip in you!
Should oil the bronze bushing. So it will last a lot longer than normal
Great video Keith. I did wonder whether it might have been possible to mill a very slight chamfer along the slot openings in that rod to reduce the scraping effect on the bushings? Best wishes.
Good idea, was thinking that, too.
Just speculating but I suspect that it might introduce a little slop by reducing the contact area. Maybe some Emory cloth and a quick rub.
1. How do the bushings get oil?
2. Could you scrape the edges of the shaft keyway to reduce the scraping action?
Keith, I would look at recessing the top of the keyway a bit. The shaft sliding and turning on that key would probably raise a burr that machines the bushing away - and is the key worn? Should be easy to run the carriage up and down to the ends and file the edges down. The worn bushings no doubt allowed the worm to shift away from the worm gear causing accelerated wear. Was there wear on the key? The shaft also might have been tapered in the center, it looked like the new bushings were tight on the end, then had tons of clearance as the working area of the shaft went in. Any looseness would mean less contact on the worm. I doubt if you will get enough wear in your shop, but it could become an issue if you sell the lathe at some point. Apologies if I am coming across as hypercritical, no offense intended! :)
Keith I think you are missing a cover on your compound to cover up the screw so chips don't get on the screw
Keith, I thought you said you bought that bushing stock from McMaster. Did you get some solid bronze, oil or PTFE embedded or ? Thanks.
Just a thought, Monarch may have taper drilled and pinned one bushing holder, then loaded in the worm the thrust bearings and a shim to ensure minimum thrust bearing lash. Then, clamp the last bushing holder in place to take the slack out of the whole stack and taper drill and pin it in place. Then pull out the shim.
because of the keyway slot in the shaft, could you hone the edges with a stone somehow that you break the edge and make it dull enough to not cut the bushings but still have enough to not damage or drop the key?
It would have to be a maintenance item. The key is regularly being rubbed into one side of the slot or the other as it slides down the shaft. Eventually would work up an edge on the shaft.
Do you mic a reamer before you bore the diameter? how long will a reamer hold its diameter?
what are then demenions on the bushings holding the feed rod on a 12 inch kk monarch lathe
Keith, some sort or lubrication for the bushing would be great considering once the bushing wear that will cause the wheel to wear all over again and it will cost another $500. Granted the key way in the shaft doesn't help this issue.
Keith, what lathe were you using to turn the bushings? It didn't look like the LeBlond and I don't recall you getting the 10EE running.
I'm curious, why not leave the extra bearing material in place to improve their longevity?
Yes, my thoughts are the same. If no interference, why not?
Could you chamfer the slot in the rod by stoning the edges to reduce the wear on the bronze bushings?
It would have to be a maintenance item. The key is regularly being rubbed into one side of the slot or the other as it slides down the shaft. Eventually would work up an edge on the shaft.
Why didn't you use the spring pin (roll pin) holes for the new set screw holes to secure the bronze bushings?
drilling them is the problem, you are drilling into half a hole, it wont go well, (broken bits wonkey hole)
I'm surprised you felt you didn't have what was needed to machine the worm wheel. I may have a similar problem on a Weiler lathe I'm rebuilding, the wheel is quite worn but I'm sure yet if it's serviceable. What equipment would be needed, maybe some kind of hob, or a form cutter and indexing equipment?
I watched a video on cutting worm gears, I believe its called Hobbing? It is a very fine machining operation that is easy to get wrong and an art form when mastered... still though $530! at the very least,I'd want to have a go!!!
That rod (shaft) that has the key way, could you break the edges on the shaft that had been cutting the bushings? I didn't notice if that had already been done. Good video again Keith; I enjoy watching the rebuilding of the old machinery, Greg.
I thought that too.
my initial thought was to put a key in place to make it a circle again... but grinding the leading edge away would be the way to go here i think...
Perhaps a dumb question, but why not skip the bushings all together and install roller bearings, or needle bearings? Or we're the bushings kept for the sake of a true restoration? Great video, regardless. I always enjoy watching you work.
It looks like the bushings need to meet 4 requirements.
They need to support the shaft as the carriage moves up and down the lathe (shaft moving axially through the bushings).
They need to support the shaft as it rotates to manipulate that worm drive (shaft rotating in either direction).
They need to work in a filthy environment. (You can't put seals on a shaft with a slot in it).
They need to not wear down the OD of the shaft.
Plain bearings (non ball, roller, needle, etc.) are going to hit all these the best.
Question, why two marks? There are only two bushings.
can stand it waiting to see it run eugggg
There was something wrong with the alignment of that shaft from the factory, possibly a design error, or manufacturing error. There shouldn’t be much side pressure on a feed shaft, so those bushings, which apparently had already been replaced, as we see, shouldn’t have had much wear. The gear, if properly aligned doesn’t push very hard against the shaft perpendicularly.
Couldn't you stone the keyway ridges?
Probably should be done on assembly, but with the key riding up and down that shaft, the edge would likely eventually sharpen as the key wears and the slot wears. The key wants to lean over in the slot and push on that edge which will sharpen it up. Maybe it's a maintainment thing to do?
One more ditto. Fortunately, it isn't too late to do that, The shaft can be slid back and forth and stoned in stages. Better not take too much off or a bevel will be created which can funnel grit and chips into the bearing surfaces. A fairly sharp edge will tend to scrape them into the keyway.
Looks like you added oil to assist you at 26:50.👍😜
maybe take a deburring tool along the keyway to break any sharp edges. Might help reduce the scraping action a bit.
It would have to be a maintenance item. The key is regularly being rubbed into one side of the slot or the other as it slides down the shaft. Eventually would work up an edge on the shaft.
was there a reason not to finish painting the bottom of the apron casting?
thats the inside or the back that bolts onto the machine face, you dont paint there
The long shaft does that only rotate or also has left to right movement? If it only turns could you not tap in a key that is as wide as the bronze bushing thus filling the key slot and maybe remove the scraping action that wears out the bushing?
or even just grind away the leading edge that is cutting the bushing?
The Rod doesn't move, but the apron runs back and forth on it. Any keyway filler would have to move with the apron along the shaft.
Ah ok. In that case there really isn't much that can be done if it's running along its length and it doesn't turn. Hence the perishable brass bushings. Could have left them longer?
Why bother shortening the bronze bushings? It seems there's plenty of room and they might last longer.
I wonder if the half nut is assembled upside down. Should it be around the shaft you put in?
There are two different shafts. One smooth with a keyway for the worm and one threaded for the half nut.
This video was about the feed rod, not the threading screw. On Monarchs there are 2 rods. Some lathes only have 1, like my ancient Hendey.
What is my dear?
My '43 SouthBend is a single shafter as well, God bless its worn out soul.
I'm going to chime in, in accord with some of the other guys. The design on that thing is atrocious. But i'd like to set forth a narrative, considering the other bearings, considering the usual Monarch methods of working their machinery, i think there was initially supposed to be an actual ball bearing in that space. That's a big lump of cast iron bearing otherwise for something that's not really all that much of a worker, in a cast iron frame. SO it's not like it was heat dissipation, and i doubt they planned on putting bronze bushings...initially. So yeah, that's my two cents on that.
Personally, i'd get two flanged bearings (UCFC205-16) and put set screws in the flanges with removed threads that engage the rod, and deal with that nuisance that way. It would also help the worm gear a bit, i don't think it likes sharing bronze shavings with the rest of the machine.
Could you not make a key for the worm to extend out both sides to the end of the bushings and mill these extensions the same size of the shaft diameter. The key extensions would support the shaft in the bushings to prevent the shaft from cutting the bushings. This wearing of the bushings is what destroyed the worm gear. Thanks for the good videos.
That would improve things quite a bit. The sharp edge develops because the relatively short key is thrusting on one side of the slot or the other as it slides down the shaft. The longer the key is, the more the thrust is divided along the length of the key. Should help with the sharpening issue quite a bit. In addition, protect the bushings from being scraped by the edges that do form. In addition, the key protruding outward of the bushings could be ramped to help eject trash out of the slot before it gets into the apron and falls in the worm mechanism.
Why you don't cover that lathe's screw.....
Fun project. Been watching them all.
One cavil: I really get bothered when I hear someone use "WD-40" and "lubricate" in the same sentence. WD-40 does many things; unfortunately, one of them is not lubricate. (Darn! Now I've just used WD-40 and lubricate in the same sentence twiceXXXXX three times.)
@kiker7sboyfriend Beer lubricates me, buddy!
27:20 Technically the small diameter one is the "Worm Gear" and the larger diameter one is the "Worm Wheel"
in the old days we threw a bone . to day trowing an arm or a leg
If you only got 2 pieces of pairs. You only need to mark ONE of the pairs.... The unmark pair is the "other pair"... hehe
If something happens to obliterate a mark, the second one saves the day.
Just think, however annoying it is to get something assembled or you get blocked putting on one part by another, there was once a guy on the assembly line that could do it all day long and in his sleep too. :-}
You only need to mark one bush if there is only two of them:-)
Just what I was going to say. Why put brass bushings back in when you could have easily bored the cast iron housings out and put ball bearings in for the shaft. Then you would never have to worry about them again.
Bushings are actually the best compromise bearing for this application. The shaft must rotate and slide at the same time.