Why does my woodruff key fall out?

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by comboprof posted 05-07-2014 12:00 PM 2160 views 0 times favorited 21 replies Add to Favorites Watch
View comboprof's profile


277 posts in 1154 days

05-07-2014 12:00 PM

Topic tags/keywords: question tablesaw woodruff

On my 20+ year old craftsman table saw the woodruff will periodically come off and disappear into the dust collector.
What can I do to prevent this? (dust collector I could usually find it on the floor.)

-- -- Cheers, Don K. (Michgan's Kewenaw peninsula)

21 replies so far

View hairy's profile


2377 posts in 2951 days

#1 posted 05-07-2014 01:02 PM

Try a few drops of superglue.

-- stay thirsty my friends...

View Craftsman70's profile


243 posts in 1544 days

#2 posted 05-07-2014 01:20 PM

Is the set screw missing from the pulley or does it not lock down on the key?

View crank49's profile


3979 posts in 2390 days

#3 posted 05-07-2014 01:38 PM

Maybe the keyseat is wallowed out or the key itself is worn down. The setscrew should normally hold everything together tightly, but if it was allowed to run loose for a long time everything gets sloppy.
A new key might help remove half the looseness.
Permatex makes products, like Loctite, to hold things together but they also will make it very difficult to disassemble if you ever need to; not impossible, just difficult.
I have known of folks using JB-Weld to fix a wallowed out keyseat in a shaft.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View Grandpa's profile


3256 posts in 2095 days

#4 posted 05-07-2014 01:57 PM

I used to have a problem like this on a Craftsman band saw. In my case it was a straight key. The woodruff key is a half moon shape but non the less mine would come out. I could tighten the set screw etc and nothing helped. It came off the motor in my case and fell into the belt guard. I bought a stick of key stock and put in a new key. In my case the stock was about 8 inches long and I cut it to length then dressed it down until it went into the slot. Try this first. That is a cheap fix with nothing permanent. As Crank said Loctite will stop the set screw from coming out. They make 3 (I believe) grades with each successive grade being more difficult to remove. I don’t think I would want to use anything stronger than the Blue or medium grade. There is also a Bulldog set screw with teeth on the bottom end to stop it from coming out easily. If the keyway is ruined the common fix in the machine shop business is to turn the shaft 90 degrees and make a new keyway. You can do this with a broach or hire it done. Bottom line about the key coming out is “sometimes it just happens”.

View Paul's profile


439 posts in 3009 days

#5 posted 05-07-2014 01:58 PM

Perhaps if you took a center punch and tapped lightly alongside the keyway you could tighten it up a tad.

-- If you say 'It's good enough', it probably isn't.

View bandit571's profile


14058 posts in 2103 days

#6 posted 05-07-2014 02:39 PM

Recheck the set screw. There SHOULD be two of them. One to hold the key in the slot, the second keeps the first from loosening up any. Only one set screw? Get a second one, and a new piece of key stock.

-- A Planer? I'M the planer, this is what I use

View Redoak49's profile


1819 posts in 1408 days

#7 posted 05-07-2014 04:24 PM

You could clean out the groove and key and then use some Lock Tite. I shy away from using a center punch on a shaft unless absolutely necessary.

View comboprof's profile


277 posts in 1154 days

#8 posted 05-07-2014 05:25 PM

Thanks for the replies. I think there is some vibration that cause the set-screw to untighten this time the blade was at 45 degrees. Perhaps it does not happen as frequently when the blade is at 90 degrees. I’m not sure. The key fits snugly in the groove so think that’s fine. Anyway I picked up some blue (medium strength) Permatex threadlocker and will dry a drop on the threads of the set-screw.

bandit571: I am mystified by your remark that there should be two set screws. Where would the second one be located? I only have the one that is on the pulley and I can’t see that there would be room for two.

-- -- Cheers, Don K. (Michgan's Kewenaw peninsula)

View bandit571's profile


14058 posts in 2103 days

#9 posted 05-07-2014 05:33 PM

On the 113 saw I have, there is space enough for two set screws in the same hole. Of course, the key stock on mine is a bar, not the bigger half moon. You might want to check that again. Maybe there IS a second set screw down inside, and it needs to be tightened down better?

-- A Planer? I'M the planer, this is what I use

View comboprof's profile


277 posts in 1154 days

#10 posted 05-07-2014 06:23 PM

I see one on top of the other. Got it. I don’t think so but I’ll look.

-- -- Cheers, Don K. (Michgan's Kewenaw peninsula)

View changeoffocus's profile


457 posts in 1037 days

#11 posted 05-07-2014 06:31 PM

If it helps, I just looked at one adjustable pulley and it has two set screws one that aligns with the keyway and the other locks down on the hub to hold the setting.
On a fixed pulley it has one set screw directly in line with the keyway.
It’s for a fan but IMO most of these are standard.
I have also had good luck with center punching the key only as some else suggested earlier.
Good luck.

View comboprof's profile


277 posts in 1154 days

#12 posted 05-07-2014 07:02 PM

Just went and took off the pulley. There is only one set screw. I put a few drops of threadlocker on it and we will see. This was the pulley on the blade arbor by the way and not the motor. Maybe the motor pulley has two set screws. I’ve never had an issue with the motor pulley so I don’t know.

Now my next trouble is the lift paddle of the on/off switch on my less than one month old DW734 planar came off. Under warranty so hopefully it will be replaced. I had to drive 45 mins to get to the “local” authorized repair shop. Meanwhile I can operate the switch with out the paddle , but is a pain. I suppose I should start a how to repair a DW734 paddle switch thread. Grrrrr I’m never going get my project done.

-- -- Cheers, Don K. (Michgan's Kewenaw peninsula)

View MrRon's profile


3891 posts in 2663 days

#13 posted 05-07-2014 07:15 PM

How can a woodruff key fall out? It is a semi-circular piece of steel that fits into a semi-circular cavity in the shaft. Once the pulley is on the shaft, the key cannot come out.

You must be talking about a straight key which is a square cross section piece of steel that slides into a groove in the shaft and pulley. If that is the case, it could fall out because the key no longer is a tight fit with the grooves. A little loctite will keep it in place. Apply to the shaft only; not to the pulley.

View comboprof's profile


277 posts in 1154 days

#14 posted 05-07-2014 08:27 PM

MrRon: Nope it is as exactly as you say a semi-circular piece of steel in a semi circular cavity in the shaft. It falls out all the time. But I agree you would think this would be impossible. I think the set screw loosens the pulley slides over enough that the key is free and falls out. Otherwise I cannot explain it.

I should mention that this all original parts that came with the saw Allso it is a 113 saw.

bandit571: I find it interesting that on your 113 say its a square key but on mine its a half circle. They must have been a change in the manufacturing. I’ll go find the model number and we can compare.

-- -- Cheers, Don K. (Michgan's Kewenaw peninsula)

View woodchuckerNJ's profile


1140 posts in 1053 days

#15 posted 05-07-2014 11:22 PM

Can’t imagine how a WOODRUFF key is falling out without the pulley moving.
A WOODRUFF is a half moon, so it just doesn’t slide out.
Sounds like your pulley is not in the right spot …

Use blue locktite on your screw that holds the key and pulley in the right spot.
if your pulley is a dual set screw, use the loctite on both screws.

-- Jeff NJ

showing 1 through 15 of 21 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics