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9" SM Utilathe Restoration
- Thread starter YYCHM
- Start date
Oooops. Won't do that again......
Today I parked the saddle a little too close to my 4J and hit the run switch. One jaw immediately locked up on the saddle.
No real damage to the saddle or jaw but man the chuck sure got torqued on tight.
Pictured is what I ended up using to break the chuck free. And no I didn't whale on it with that hammer, just a few well placed taps on the end of the bar did the trick. It's an awkward one handed maneuver as you need to hold the head stock pulley with one hand and swing with the other. If I could have gotten both arms going on that bar I could have probably pulled it loose.
Today I parked the saddle a little too close to my 4J and hit the run switch. One jaw immediately locked up on the saddle.
No real damage to the saddle or jaw but man the chuck sure got torqued on tight.
Pictured is what I ended up using to break the chuck free. And no I didn't whale on it with that hammer, just a few well placed taps on the end of the bar did the trick. It's an awkward one handed maneuver as you need to hold the head stock pulley with one hand and swing with the other. If I could have gotten both arms going on that bar I could have probably pulled it loose.
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That's a good question. Threading usually has the compound set at the magic angle so that the leading edge (only) of the threading insert is fed & doing the cutting. Now that's kind of similar to one kind of regular turning insert geometry, but different than many others which may be zero, plus or minus degrees relative to feed. Having said that, many threading inserts actually say OK to feed straight in perpendicular to lathe axis up to a certain thread size, no compound pre-set. And technically a threading tool nose radius is defined based on the thread size itself, so you may not have much choice in the matter.
I find MY threading speeds are so pathetically low relative to any kind of typical turning guideline purely because I personally feel crashing into the chuck is not conducive to long term lathe health or my bank account balance LOL. Unless you have some lightning speed reflexes to disengage threading or reverse threading or dynamic brake... the real life constraints tend to dictate the operation.
I find MY threading speeds are so pathetically low relative to any kind of typical turning guideline purely because I personally feel crashing into the chuck is not conducive to long term lathe health or my bank account balance LOL. Unless you have some lightning speed reflexes to disengage threading or reverse threading or dynamic brake... the real life constraints tend to dictate the operation.
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historicalarms
Ultra Member
Yup...lots of antidotal write-ups in old publications about the dangers of threading a chuck tighter under power...if it make a KA-THUNK when it comes tight...an equal KA-THUNK will be required to remove the chuck.
Back in the days before the D mounting system when every chuck was threaded, lots of reading material about having to machine the chuck back plate off in the case of 3-jaws and the entire chuck body in the case of one 16" 4-jaw that I read. From the story, it stated that the lathe operator was installing the chuck and had it just spudded on a thread or two when a tool was dropped and hit the "go" lever on the lathe...it was set at 1000 rpm and the whole shop heard that chuck come up tight to the spindle. some attempts were made to mechanically hold the spindle and remove the chuck but it seems that it was quickly realized that damage to the headstock-spindle would occur before removal so the lathe operator was instructed to machine the chuck body from the lathe...his employment was ceased with the last cut, it was reported.
Recent Youtube discussing some of the same screw on / back plate issues thread & concentricity issues.
ps - this isn't the first time I've heard about some of the cheapo 5C chucks being gronked together with either high torque on the screws or permanent Loctite or whatever. I'm sure there is a way to remove but kind of too bad because sometimes these parts can be treated as 'kits' that you can tweak into a decent tool ala Stefan. But you have to get in there first. (I would bet a coffee the scroll teeth are probably the root issue, not grit).
ps - this isn't the first time I've heard about some of the cheapo 5C chucks being gronked together with either high torque on the screws or permanent Loctite or whatever. I'm sure there is a way to remove but kind of too bad because sometimes these parts can be treated as 'kits' that you can tweak into a decent tool ala Stefan. But you have to get in there first. (I would bet a coffee the scroll teeth are probably the root issue, not grit).
I oil my spindle threads on the old von wyck lathe and make sure the chuck threads are spotless when turning on the chuck. The 4 jaw is a 12” and weighs about 80 pounds. It’s ka-thunk is pretty audible when you spin it on nicely ..... can’t imagine if you crash it
I try and make a habit of taking off the chucks when I’m done as a couple of times I’ve had to chuck up a piece of 2x4 and apply some persuasion to break the seal
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I try and make a habit of taking off the chucks when I’m done as a couple of times I’ve had to chuck up a piece of 2x4 and apply some persuasion to break the seal
Sent from my iPhone using Tapatalk
I finally got fed up with my apron leak and opened it up.....
All the external shafts are above the oil fill level so it must be the leaking from the housing. The gasket material that was used is next to non existent. The good news is that all the internal gears etc appear to be in great shape. The pinion gear does show some wear, but not a lot.
What do you suggest I use for a gasket? Would an instant gasket in a tube work, that is what was on it. Would cardboard work?
@Hruul , @YotaBota what did you guys use?
Craig
All the external shafts are above the oil fill level so it must be the leaking from the housing. The gasket material that was used is next to non existent. The good news is that all the internal gears etc appear to be in great shape. The pinion gear does show some wear, but not a lot.
What do you suggest I use for a gasket? Would an instant gasket in a tube work, that is what was on it. Would cardboard work?
@Hruul , @YotaBota what did you guys use?
Craig
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Chicken lights
Forum Pony Express Driver
That’s arguably the best gasket maker out there. Or you could make a gasket from gasket paper, smear some regular black silicone on the paper both sides before assembling
Lots of ways to do it
@YotaBota , @Chicken lights where did you source your gasket goo from?
Gregg Distributors carry the full line of Permatex Products
https://greggdistributors.ca/search?q=Permatex gasket&resp_group=Default,Variations,ItemProperties
https://greggdistributors.ca/search?q=Permatex gasket&resp_group=Default,Variations,ItemProperties
Chicken lights
Forum Pony Express Driver
NAPA, Fort Garry, Traction, they all should have it or can get it, or similar places
As RobinHood and CL suggest, a local jobber should be able to supply you something that works.
Failing that you could order from aircraft spruce, https://www.aircraftspruce.com/catalog/eppages/permatexprod4.php?clickkey=483329
Mine is left over from my airplane days and it's been around for a while and still works well.
Failing that you could order from aircraft spruce, https://www.aircraftspruce.com/catalog/eppages/permatexprod4.php?clickkey=483329
Mine is left over from my airplane days and it's been around for a while and still works well.
I'm kind of curious about this too. I've put some aluminum parts together with various gasket makers & the problem was it stuck too good. I had a heck of a time parting them. His apron is a more rigid piece of iron where some leverage would shear the goop & not probably distort the part. But generally for oil holding seals like this, should there be a gasket plus goop as opposed to goop alone? What does it depend on?
Chicken lights
Forum Pony Express Driver
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For seals we always used to use Loctite plus grease or tranny assembly lube to help seat things
Sometimes silicone on the outside of seals or loctite then grease or assenbly lube on the inner part to lock the spring in place
Interesting question. I’ve never been worried about disassembly so much, as I’m more worried about leaks.
For seals we always used to use Loctite plus grease or tranny assembly lube to help seat things
Sometimes silicone on the outside of seals or loctite then grease or assenbly lube on the inner part to lock the spring in place
historicalarms
Ultra Member
Not sure where your oil level is in the case ( you say lower than all the shafts) but , for my money I would want a deeper oil reservoir than that bottom shaft shown. the shaft outlet on that cover has no seal or gasket provision so I think maybe your oil seep originates from that shaft. I know the carriage gearbox for my "China Doll" has a constant oil seep from the shaft journals on the inside face.
A couple of points on gasket material. Like Chicken, I have basically gone away from paper gaskets and use strictly goop of one brand or another ( they all seem to work) unless it is something built that only a thick paper gasket will work. The thing is that on most aplications, gooped up pieces can be tightened but not over tightened and work fine.
The thing with thick paper gaskets is that they need to be tight but not over tightened especially with cast or alum. box's. They are brittle and can crack between bolts if tightened too much. The paper gasket will compress at the bolt positions but the casting will bend & crack between them.
I would use paper gasket only on a top "splash cover" that doesn't have oil bath to hold in over long periods of time....goop in your apron case.
My (Taiwan 14x40) lathe similar shafts riding in holes in the cast iron apron casting. But I think mine is the last of the vintage before they went oil bath apron. You could pull a parts manual of some of these machines to see how the sealed. I suspect some kind of O-ring or rubber washer, but maybe inset into a machined groove. To avoid machining & experimenting I've read where people have siliconed a loose fitting rubber washer on the casting face. The excess goop makes kind of a fillet around the shaft. When cured breaks free from the shaft (acting as kind of a mold). I'm not sure if the shaft is treated with something like a release agent? Sounds a bit ghetto & never tried it but sometimes that's all it takes.
Brent H
Ultra Member
@YYCHobbyMachinist : make sure you clean off all the old liquid gasket and then use acetone or some other non residue cleaner to be sure both plates are oil free. Apply a thin amount of the sealant as you do not want it gumming up your gears - once you re-assemble let it fully cure before you add oil. I cannot recall any gasket or sealant on the donor lathe. If the apron piece is still in the junk bin I will see if there is any tell tail signs.