Grub screws

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STRR
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Re: Grub screws

Post by STRR »

If you choose to drill and tap the split between the shaft and hub, BE SURE to match mark the two as you have them drilled originally. When you take them apart in the future, you'll be glad you marked them as you reassemble.
pete
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Re: Grub screws

Post by pete »

There's not enough information given to provide an accurate answer to your question. Is this a plain coupling you've already bought without any keyway already in it? Or are you asking about the best way to use a coupling you haven't bought yet? I guess it's not impossible plain couplings are out there, but I'd be surprised most wouldn't already come with some type of method of locking the coupling to the shaft to prevent rotation. What does the shaft on that alternator use? As others have already said, a grub screw with even a flat machined on the shaft is a poor very low torque method that almost for sure is going to give problems. And yes some pulley's and couplings do come with set screws that bear against a woodruff or straight key, but the key itself takes all the torque load.Even most half decent lathes above a 7"-8" swing use some type of keyway for the hand wheels and the loads are certainly far less than that alternator drive would see.
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Bill Shields
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Re: Grub screws

Post by Bill Shields »

Many Lovejoy type of couplings come "rough pilot bore" with no keys or screws.
Too many things going on to bother listing them.
Richard_W
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Re: Grub screws

Post by Richard_W »

armscor 1 wrote: Sun Dec 05, 2021 5:00 pm Commonly referred to as a Dutch Key.
I am from Dutch heritage but have no idea how the name came about.
For the last 50 years I have only heard it called a dutch key. Sometimes it the way they do it on new equipment.

Richard W.
pete
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Re: Grub screws

Post by pete »

Thanks Bill, that's not something I knew.
Russ Hanscom
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Re: Grub screws

Post by Russ Hanscom »

On some automotive alternator applications, the pulley is pressed onto the shaft, no key or other retaining method. With the correct fit, obviously works.
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Bill Shields
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Re: Grub screws

Post by Bill Shields »

Russ Hanscom wrote: Tue Dec 07, 2021 10:30 am On some automotive alternator applications, the pulley is pressed onto the shaft, no key or other retaining method. With the correct fit, obviously works.
very true -> but you need to be careful with small OD LJ type of couplings -> the shrinkage needed to make this type of 'grip' work can cause the coupling (particularly if pot metal) -> to crack along the axis.

Pulleys have the advantage of greater diameter and ability to handle the press fit.
Too many things going on to bother listing them.
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liveaboard
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Re: Grub screws

Post by liveaboard »

Automotive usually uses a flange fit and self tightening nut. Some have keys.

I've worked with many, and modified a few.
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