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Those two quotations is why I buy my farm equipment bearings off Ebay. I don't need aircraft certified quality and I don't need to pay the counterman at Napa (the one who can't find the bearing I need anyway). I simply use the bearing number if it is still visible or the OD, ID, thickness and seal type. It also lets me do the order on my free time and without the 40 mile round trip to town plus waiting for a counterman to notice me.
yUp, 40 round trip is certainly a show stopper for a silly bearing. I only have about 1-1/2 miles one way. I also bought a 3/8 key stock section, 12". It was solid steel. the NAPA equivalent had some kind of coating on it. I prefer the non-coated
 
has anyone come up with a reason the motor key has that plastic key with a smaller metal peice in the middle? It only makes sense if the plastic is to reduce shock on start up or maybe reduce vibration but, to me, neither is really a good reason.

Ah, was just examining the mechanism--turns out the key slides as the pulley expands. Mystery solved, but now I REALLY don't like it. Will have to make a piece that self lubricates, can take the pressures involved and won't break with that hole in it. I have some stuff that may work. Hmmm.
 
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Ladies and Scholars:
I have a fun problem that I dread starting, so I thot maybe y'all could make some suggestions.

This Bridgeport motor shaft has been damaged. Maybe I tol' y'all about it earlier, that I was commplaining about a plastic key having broken, the metal key put in the middle of it being completely destroyed and the screw nowhere to be found. I've completely disassebled the head and that screw is STILL nowhere to be found.

Well, here is the result of the destruction as far as the motor shaft goes.

The one photo makes it look like it actually has a crack in it, Will take a closer look at that--hard to see with naked eye.

besides completely replacing this or the motor, I thimpfks there may be three or more possible solutions: epoxy (not my favorite idea), metal bond (never had any experience with it), Brazing (might work), and TIGging, This last one is my favorite, however, I'm thimpfking that might get the shaft too hot. Any ideas?
 

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Well, after a careful examination, there is no crack, just looks like it in that photo. My son suggests putting a piece of ceramic backing in keyway and TIGging it. MIght work if I can find a piece of ceramic that would fit in it. I thimpfks his other suggestion is better, just tig it then use a dremel on it..

I'll have to clean that really well, no matter what I do, so acetone?
 
Ladies and Scholars:
I have a fun problem that I dread starting, so I thot maybe y'all could make some suggestions.

This Bridgeport motor shaft has been damaged. Maybe I tol' y'all about it earlier, that I was commplaining about a plastic key having broken, the metal key put in the middle of it being completely destroyed and the screw nowhere to be found. I've completely disassebled the head and that screw is STILL nowhere to be found.

Well, here is the result of the destruction as far as the motor shaft goes.

The one photo makes it look like it actually has a crack in it, Will take a closer look at that--hard to see with naked eye.

besides completely replacing this or the motor, I thimpfks there may be three or more possible solutions: epoxy (not my favorite idea), metal bond (never had any experience with it), Brazing (might work), and TIGging, This last one is my favorite, however, I'm thimpfking that might get the shaft too hot. Any ideas?
Well - - - I've done this more than once or twice - - - but its not a lot of fun and if done well - - - you can have almost a new shaft.
1. take apart totally
2. check for straightness (quite important)
3. I welded up the shaft using either sick or mig but in the round so there's like a snake around the shaft
(Don't need tig unless you're already comfortable with it!)
You need to weld hot enough so that there is NO porosity in the weld and that you have good adhesion to the shaft!
(using mig keep your volts up! - - - you're looking for a strong sound weld not necessarily a beautiful one!)
I would suggest welding right through the keyway - - - much easier than trying to get a good weld, the right amount of build up and not touch the keyway.
You might need to put the shaft down a couple times in the welding - - - -you do NOT want the shaft to be red hot at the end of the welding.
(At least imo anyway!)
4. let the shaft cool slowly
(putting it into a roll of insulation works, putting it into DRY sand works - - - you want slow cooling!)
(minimizes change - - - I'm assuming the shaft is a better quality steel than 1018 or similar)
5. machine the shaft in your lathe (filing would take forever!!!!)
6. machine the keyway clean
7. assuming you've done a good good machining - - - time to re-assemble (check for straightness unless you've done it earlier - - - should be good!)
I'd almost want to use new bearings but that's not necessarily important - - - - depends upon what the chancellor of the exchequer says (grin!)
8. you should be good to go

(That should be a good part of a day's job doing it but when you're done - - - unless you tell them it shouldn't be easy to see the fix!)

HTH
 
Well - - - I've done this more than once or twice - - - but its not a lot of fun and if done well - - - you can have almost a new shaft.
1. take apart totally
2. check for straightness (quite important)
3. I welded up the shaft using either sick or mig but in the round so there's like a snake around the shaft
(Don't need tig unless you're already comfortable with it!)
You need to weld hot enough so that there is NO porosity in the weld and that you have good adhesion to the shaft!
(using mig keep your volts up! - - - you're looking for a strong sound weld not necessarily a beautiful one!)
I would suggest welding right through the keyway - - - much easier than trying to get a good weld, the right amount of build up and not touch the keyway.
You might need to put the shaft down a couple times in the welding - - - -you do NOT want the shaft to be red hot at the end of the welding.
(At least imo anyway!)
4. let the shaft cool slowly
(putting it into a roll of insulation works, putting it into DRY sand works - - - you want slow cooling!)
(minimizes change - - - I'm assuming the shaft is a better quality steel than 1018 or similar)
5. machine the shaft in your lathe (filing would take forever!!!!)
6. machine the keyway clean
7. assuming you've done a good good machining - - - time to re-assemble (check for straightness unless you've done it earlier - - - should be good!)
I'd almost want to use new bearings but that's not necessarily important - - - - depends upon what the chancellor of the exchequer says (grin!)
8. you should be good to go

(That should be a good part of a day's job doing it but when you're done - - - unless you tell them it shouldn't be easy to see the fix!)

HTH
#2 should be stick NOT sick! (edit didn't want to work!!! - - - - argh!)
 
#2 should be stick NOT sick! (edit didn't want to work!!! - - - - argh!)
Yeah, I got that. Well stick is out. Would NOT use stick. Never thot of MIG, however, even so, it seems to me that there is much more precise control with TIG. When you say you weld round it like a snake, that could mean a couple things. Could you explain more or draw a picture?

Thanx for the "red-hot" precaution and also for the "cool down" technique. ONe of my big worries is that no matter what technique is used, it is going to warp the thing. You say you done this a few times?

I will have to file it as this is the only mill I have, it would be like giving yourself brain surgery, not very easy. It will take me more than a day.
 
i know you said stick is out.
but, I would use this process rather than mig.
even ER60 mig is hard to machine or file.
7018 or even 6013 would be my preference (I know nothing about TIG so cannot commen on that) but a number of short stick welds over a time period so shaft wouldn’t get too hot. And it would be machineable or fileable or carbide burr able.
that’s all I got, good luck with whatever you do.
 
i know you said stick is out.
but, I would use this process rather than mig.
even ER60 mig is hard to machine or file.
7018 or even 6013 would be my preference (I know nothing about TIG so cannot commen on that) but a number of short stick welds over a time period so shaft wouldn’t get too hot. And it would be machineable or fileable or carbide burr able.
that’s all I got, good luck with whatever you do.
i thimpks stick has too much slag probs, however one could break off thecovering and use that for the filler with TIG. I know one fella who did that, forget why but he seemed pretty confident.

In the meantime I have discovered the cast iron pulley that fits on the spindle also has a nasty gouge. This is on the INSIDE which makes it more difficult to weld. Have you ever welded CI? I'm thimpfking this is definitely a weird job for TIG, however, I am not sure one can TIG cast. I woujld thimpfk one could but not sure. Weld maybe half an inch, then allow it to cool--can't pein inside that little hole
 
Ladies and Scholars:
I have a fun problem that I dread starting, so I thot maybe y'all could make some suggestions.

This Bridgeport motor shaft has been damaged. Maybe I tol' y'all about it earlier, that I was commplaining about a plastic key having broken, the metal key put in the middle of it being completely destroyed and the screw nowhere to be found. I've completely disassebled the head and that screw is STILL nowhere to be found.

Well, here is the result of the destruction as far as the motor shaft goes.

The one photo makes it look like it actually has a crack in it, Will take a closer look at that--hard to see with naked eye.

besides completely replacing this or the motor, I thimpfks there may be three or more possible solutions: epoxy (not my favorite idea), metal bond (never had any experience with it), Brazing (might work), and TIGging, This last one is my favorite, however, I'm thimpfking that might get the shaft too hot. Any ideas?

Have you considered LASER welding it? From my reading, I understand it produces much less heat in the base metal, which means less chance of warping your shaft. One of my machine shop friends here in Thailand loves it, he posted this video on his FB page: Laser Weldler
 
Have you considered LASER welding it? From my reading, I understand it produces much less heat in the base metal, which means less chance of warping your shaft. One of my machine shop friends here in Thailand loves it, he posted this video on his FB page: Laser Weldler
That's really nice, but I don't have one of those. Thailand is too far to ship and return too.
 
Hi Richard, In my (small and limited)experience, you should (SIF-) Bronze braze cast-iron pulleys that have cracked. Not sure about the "SIF" alloy, in case that has Cadmium in it, just use a "regular" brazing rod with the correct flux. (Flux the job well from cold and you get a really clean metal for the braze to "take" to).
Also for a steel shaft I would use stick - as I know some people are adverse to the slag, but professional welders get on with it and it really is a good solution to getting the right alloy rods and enough heat into the weld for good penetration. Or MIG.
One job I was on, we were MIG welding 1/2" welds in aluminium (joining 4" and 6" thick bars) and 5mm and 6mm rods onto cast steel components. - The welding Engineer had specified the size, material and current for the Rods (stick), not MIG, for the power needed for the size of weld penetration. I don't think TIG goes anywhere near that size of weld (Current), not that you will either. Slag removal should not be a problem, just time and care, which I know to be a good part of all your work.
Is it not easier to start with a new piece of steel and machine a new part?
Alternatively, instead of welding (are you just in need of repairing a gouged bit of shaft?) you may be able to braze fill the "bruise" cavities with the bronze - which should really minimise distortion compared to welding. How deep are the "bruises"?
A temporary repair may be a good quality epoxy "metal mender" (one of the filled resins, not clear liquid!), I am a bit vague... is the shaft just bruised so you need to fill less than 0.1" of cavity? Maybe a temporary repair will get the lathe fixed so you can use it to make a new shaft from scratch?
Or perhaps another "local" Engineer can make you one? ( I am in the UK, 8 miles from the original Washington, so just too far to drive to your Washington!).
Sorry I don't have any clever ideas, but Bronze brazing is my preferred method for many things, as it heats the whole job and minimises distortion on many repairs, especially on cast iron. Or you end-up heating the cast iron red hot before welding.... (and no advantage over brazing, except when repairing gear teeth).
Cheers,
K2
 
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Hi Richard, In my (small and limited)experience, you should (SIF-) Bronze braze cast-iron pulleys that have cracked. Not sure about the "SIF" alloy, in case that has Cadmium in it, just use a "regular" brazing rod with the correct flux. (Flux the job well from cold and you get a really clean metal for the braze to "take" to).
Also for a steel shaft I would use stick - as I know some people are adverse to the slag, but professional welders get on with it and it really is a good solution to getting the right alloy rods and enough heat into the weld for good penetration. Or MIG.
One job I was on, we were MIG welding 1/2" welds in aluminium (joining 4" and 6" thick bars) and 5mm and 6mm rods onto cast steel components. - The welding Engineer had specified the size, material and current for the Rods (stick), not MIG, for the power needed for the size of weld penetration. I don't think TIG goes anywhere near that size of weld (Current), not that you will either. Slag removal should not be a problem, just time and care, which I know to be a good part of all your work.
Is it not easier to start with a new piece of steel and machine a new part?
Alternatively, instead of welding (are you just in need of repairing a gouged bit of shaft?) you may be able to braze fill the "bruise" cavities with the bronze - which should really minimise distortion compared to welding. How deep are the "bruises"?
A temporary repair may be a good quality epoxy "metal mender" (one of the filled resins, not clear liquid!), I am a bit vague... is the shaft just bruised so you need to fill less than 0.1" of cavity? Maybe a temporary repair will get the lathe fixed so you can use it to make a new shaft from scratch?
Or perhaps another "local" Engineer can make you one? ( I am in the UK, 8 miles from the original Washington, so just too far to drive to your Washington!).
Sorry I don't have any clever ideas, but Bronze brazing is my preferred method for many things, as it heats the whole job and minimises distortion on many repairs, especially on cast iron. Or you end-up heating the cast iron red hot before welding.... (and no advantage over brazing, except when repairing gear teeth).
Cheers,
K2
I thimpfk brazing may be a great repair for the cast iron part but not so sure about the motor rotor. The rotor has all that magnetic steel on it so not going to try to make a new one. As for the gouges size, try to judge that from the photo and my hand size. I thimpfk that brazing might be good on the steel shaft also as long as the "system" has no mishaps like the first one. The gouge is about an 1/8th" deep on one end, and tapers off. Since I have no history of what happened to this engine, I can only surmise by what I see.

What I have seen is the ways seem fine, the surface of the mill is fine but the grease inside the bullgear was . . . gone! Used up, a small remainder was there, of course but none in contact with the gears. How this grease disappeared, I'd like to know--maybe someone had it apart and didn't replace the grease. The bearings on the shafts are dry (remember these are 6010 2rs bearings, sealed on both sides) but a bit rough. If I had to, I could put it back in, tho' not a good idea since I know it's bad.

So it looks like the mill was basically used well, that is, basically taken care of and not bruted--it had a lot of aluminum chips in it but maybe a novice had been using it and failed to oil/greese it and/or notice that it was noisy or not keeping tight cuts. Frankly, this is only conjecture, I really don't have a clue as to how it was treated, just that most likely the parts workt loose and broke, then twisted around and the small metal insert key (this is a two part key with plastic and an embedded metal part) workt it's way around and finally failed completely. Tomorro I will try to remember to dig out the key and photo it--very funni twist. ha ha. I was watching utub repair vids and there seems to be quite a lot of these plastic keys failing. The screw hole makes a weak spot that the designers apparently don't understand. Frankly, I'm surprized these don't fail in less than a week.
 
Yeah, I got that. Well stick is out. Would NOT use stick. Never thot of MIG, however, even so, it seems to me that there is much more precise control with TIG. When you say you weld round it like a snake, that could mean a couple things. Could you explain more or draw a picture?

Thanx for the "red-hot" precaution and also for the "cool down" technique. ONe of my big worries is that no matter what technique is used, it is going to warp the thing. You say you done this a few times?

I will have to file it as this is the only mill I have, it would be like giving yourself brain surgery, not very easy. It will take me more than a day.
Ja - - - tig control is more precise - - - - but you're just laying down metal and unless you're pretty good at tig mig is a LOT faster.

Snake - - - think like a spring - - - you know round and round we go - - - - like winding a spring.

Well - - - the red hot - - - - its easy to do on a smaller shaft - - - say under 1.5" dia - - - harder on a 2.5 or 3".

Warping happens much more easily is you shock cool something.
Shock cooling is a great tool when you're trying to straighten something that's been badly warped/bent but you don't want that here.

You don't have a lathe?

I said to use a lathe to turn it round.

I'd bet you're thinking of the keyway - - - - well then you will need to file the keyway true.
That's still a heap less filing than putting some material on the surface in spots and trying to file the thing clean and hoping you haven't increased any warpage in the shaft.
 
i know you said stick is out.
but, I would use this process rather than mig.
even ER60 mig is hard to machine or file.
7018 or even 6013 would be my preference (I know nothing about TIG so cannot commen on that) but a number of short stick welds over a time period so shaft wouldn’t get too hot. And it would be machineable or fileable or carbide burr able.
that’s all I got, good luck with whatever you do.
I find 6013 to be a rod that is very difficult to not get slag inclusions on.
In the trade it is called 'farmer rod'.
You get a beautiful looking weld that is all too often not terribly strong. (You want penetration and 6013 is light on that unless your heat is way up there!)
I would use 6011 (buzz box) or 6010 DC long before I would use 6013.
If you want beautiful welds - - - well work with the 7018 a bit more - - - at least then you have a fighting chance for enough strength!

I didn't even think of using a air grinder driven burr for cleaning out the keyway - - - LOL - - - that would make it quite easy.
(Air grinders can be quite hard on the hands in these kind of functions - - - not saying anything about their use - - - just pitching out a warning so it doesn't hand someone RSI because they over did it!)
 
i thimpks stick has too much slag probs, however one could break off thecovering and use that for the filler with TIG. I know one fella who did that, forget why but he seemed pretty confident.

In the meantime I have discovered the cast iron pulley that fits on the spindle also has a nasty gouge. This is on the INSIDE which makes it more difficult to weld. Have you ever welded CI? I'm thimpfking this is definitely a weird job for TIG, however, I am not sure one can TIG cast. I woujld thimpfk one could but not sure. Weld maybe half an inch, then allow it to cool--can't pein inside that little hole
IMO repairing a small bore is better done by machining the bore larger and inserting a sleeve.
If you want a very strong way of doing that - - -
1. machine bore to some at least 1/4" larger radius than the hole.
2. machine a plug and make it to about 0.0005 to 0.001" bigger in OD than the ID of the enlarged hole.
3. if worried about holding drill 3 - 3/16" holes at close to 120 degree spacing in the interface between the plug and the pulley hole.
3a. drive in 3/16" pins and mushroom the ends
4. now machine the bore
5. you have a true strong and accurate fix (should be good for the klife of the machine if there aren't some other flaws somewhere else that cause things to go kittywumpus again.

Its not a strong to make a very thin sleeve and the take only a wee bit off the bore but that's also a possibility.

With tig - - - cast iron - - - well best is a piece of the original and away you go. (that's how they fix piano frames - - - grin!)
 
Ja - - - tig control is more precise - - - - but you're just laying down metal and unless you're pretty good at tig mig is a LOT faster.

Snake - - - think like a spring - - - you know round and round we go - - - - like winding a spring.

Well - - - the red hot - - - - its easy to do on a smaller shaft - - - say under 1.5" dia - - - harder on a 2.5 or 3".

Warping happens much more easily is you shock cool something.
Shock cooling is a great tool when you're trying to straighten something that's been badly warped/bent but you don't want that here.

You don't have a lathe?

I said to use a lathe to turn it round.

I'd bet you're thinking of the keyway - - - - well then you will need to file the keyway true.
That's still a heap less filing than putting some material on the surface in spots and trying to file the thing clean and hoping you haven't increased any warpage in the shaft.
Yes, turn it round on the lathe--no problem. I was thimpfking of cutting the slot--not possible if the mill is operating on it's own parts.
 
Hi Richard,
Sometimes it is possible to re-configure the mounting of the part and tool - such as setting the shaft on V-blocks clamped on the cross-slide, using a DTI in the chuck so you get it perfectly square to the rotation axis of the lathe main-shaft, and fitting the milling cutter in the chuck/collet on the lathe main-shaft? Shimmed up to adjust the height of the workpiece adjusts the side-cut of the tool in one plane, depth of cut is by moving the saddle, and length of cut (keyway) is using the cross-slide? But it really depends on size of lathe versus shaft as to whether you can set-it up.
Or a trip to your mate "down the road"...? (I have lots of useless suggestions that my imagination can explore).
K2
 
Ajoeiam, re post #245: Distortion after welding is usually a combination of the size/stiffness of the parent part, and the amount of weld and heat input.
Simply: The weld is molten, so when it "freezes" and becomes attached to the already "frozen" parent metal, it is cooling from a state that is hotter than the parent metal. The differential contraction as parent metal and weld metal cool cause internal stresses at the weld interface... and if great enough to distort the parent metal it is these stresses that cause distortion. Uneven cooling can make that condition worse, as we tend to cool parts with quenching "the far end" of the part, but this can cool the parent metal faster than the weld and exacerbate a problem that is inherent in the welding process. Pre-heating and normalising are simply ways to reduce weld stresses, thus reducing distortion. But microscopically, all weld repairs distort parent metal because we lay and bond molten metal onto cooler "frozen" metal. It is just that we can get away with some very small distortion when it is so small it is within tolerance.
K2
 
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