factional HP gast vane pump

My new-old stock gast rotart vane pump just died. I though it broke a shear pin as only the motor was still spinning. I know, it makes no sense
to have a have shear pin in a small tabletop style pressure/vacuum pump.
Apparently the rotor was held to the motor shaft with some sort of loctite, at least according to the manual and it broke free. The shaft is round and nearly polished, same for the bore of the rotor. The service manual says sent it to a repair depot and never mess with the rotor. Forget that.
What's the best loctite to attach the 1/2" shaft to the about 2.5" diameter rotor? They will be wet at all times with light motor oil, and the runnning temp is too hot to touch for more than a few seconds. I've not used loctite under those conditions.
The stuff that broke free looks slightly yellow, like 5 minute epoxy of some type.
It just seems like real cheap, shitty design to me. I've never seen the inside of pump held together with glue.
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Of course after hitting post I did locate some henckel 243 which is alleged to be the oil resistant blue stuff. I don't have any super thin skinny aircraft type bits to get in there unless the end bell of the motor comes off. This is a single casting that acts as the side of of the pump and holds the motor together. Not sure of they added some obnoxious seals in there so we'll just see if the blue stuff works.
Still baffled by the rotor glued to a shaft design. It's not even an interference fit.
What's the name for installing a roll pin in the direction of a shaft, sort of like how a square key sits? That might be the lazy next option.
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On Sun, 26 Mar 2017 18:29:54 -0400, "Jim Wilkins"

Around here a Dutchman is an inlaid patch, most often a repair to a defect in a wooden piece. I know the device under discussion as a Dutch pin.
The problem drilling the joint between different materials can be minimized by starting the hole with an end mill as close as possible to the desired size, then enlarging, if necessary, with a drill. Still can be pucker-inducing.
My preference is for a tapped hole and set screw instead of a pin. Easier to disassemble, less fussy than fitting a pin, and also retains the mounted component in the axial direction.
--
Ned Simmons

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I second that for a steel hub on a steel shaft. Otherwise tapping along the joint bertween dissimilar materials is worse than drilling.
If the hub is softer than the shaft I broach a keyway in it. The necessary guide is easy to turn to whatever size the hub bore may be. You can set the broach cutting depth to not weaken the hub too much, and adjust the cutting depth with shims sheared from hobby store brass or tin cans.
I mill a key slot in the shaft and then make a key that's a snug fit in the shaft and perhaps a looser one in the hub if there's space for a setscrew. The width of the key is easier to adjust than the slots' because you can use a larger, stiffer endmill.
The key can be stepped without much trouble if the slots are different widths, for example if a 1/8" shaft slot needs extra cleanup passes.
-jsw
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On Mon, 27 Mar 2017 09:00:22 -0400, "Jim Wilkins"

Though not as easy to remove, a broken tap is as secure as a setscrew. <g>
Last time I remember doing this was mounting a herringbone sprocket
bored out to just below the teeth (~8" ID?) on a large hollow machine tool spindle. The sprocket was free machining steel, the spindle was pre-hard 4140. Nerve wracking, but there's a couple set screws in the assembly, no broken taps.
--
Ned Simmons

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The cast aluminum handwheel on my lathe's collet closer is attached to the steel tube with two axial setscrews which are more in the aluminum than in the steel. It certainly can be done by someone with more skill than I have. -jsw
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wrote:


I did this on my sail line reel, aluminum hub, aluminum plate flanges. I shrank on the flanges, but not knowing the spreading force of 1000 yds. of 100 lb. monofilament, decided better safe than sorry. Worked great.
Pete Keillor
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wrote:

Yes, whose pointed tip seats in the small conical depression in the shaft cut by the drill bit. I drill in place, ensuring that it is lined up. Then I remove the sleeve or gear, and tap it and run a file or stone across the tapped hole to debur. A drop of Loctite helps it stay there for a long time.
--
The more you know, the less you need.
-- Aboriginal Saying
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On Saturday, March 25, 2017 at 4:52:27 PM UTC-4, Cydrome Leader wrote:

Where do you live? At times the scrap yard gets some medical hardware. Like pumps from oxygen concentrators. They get two sizes of pumps.
Dan
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Chicago. Pump is running again now for the time being without modifications. Did chip part of the "stone" in the output filter that traps some of the oil vapor, so need to patch that with something.
Used medical stuff always looks too gross to deal with. The stuff is either dirty, destroyed by cleaning an sanitizers or both.
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On Saturday, March 25, 2017 at 4:52:27 PM UTC-4, Cydrome Leader wrote:

Leery of posting any metalworking advice since I know so little about it, but couldn't the motor armature be put in a lathe and the shaft knurled? Then press on the pump impeller?
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Yes, but then the shaft would not fit though the bearing and casting that makes up one side of the pump. They've combined that into one bell for the motor itself to cut down on parts and price.
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On Saturday, April 8, 2017 at 4:34:00 PM UTC-4, Cydrome Leader wrote:

Understood.
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