Mark V Control Sheave Replacement Issue

[Bruce]

Thanks Bill and JPG for the quick responses. Here are the pics. The shaft key and my old control sheave key way are both 0.4 cm (4 tenths of a centimeter) and the NEW sheave key way is 0.3 cm (exactly 3 tenths of a centimeter) (Yes I know you guys are woodworkers and know how to measure but just making sure I'm being clear in my descriptions.

Shaft Key.jpg

Old Control Sheave Key way.jpg

New Control Sheave Key way.jpg

Is it my imagination or is the casting for the new sheave incomplete? It looks like there's some metal missing and maybe a small crack. I've never had one apart, so I may be imagining it.

[wa2crk]

OK my first post went south when I tried to review the pics. The rounded corner on the upper right of the keyway in the pic indicates ( to me anyway) that the bad bearing caused the sheave to wobble and cause the wear. The marks on the key are probably from the set screw. Also the edges of the keyway on the shaft seem to show some wear which could have been caused by a loose and worn keyway.
If this were mine, or I was doing it for someone I would replace both sheaves and the key. ( I like to err on the side of longevity )
The key can be replaced or filed and the edges of the keyway on the shaft can also be be filed but there may still be some slight binding after filing.
Again, if it were mine I would bite the bullet.
Bill V

[Teggy]

OK my first post went south when I tried to review the pics. The rounded corner on the upper right of the keyway in the pic indicates ( to me anyway) that the bad bearing caused the sheave to wobble and cause the wear. The marks on the key are probably from the set screw. Also the edges of the keyway on the shaft seem to show some wear which could have been caused by a loose and worn keyway.
If this were mine, or I was doing it for someone I would replace both sheaves and the key. ( I like to err on the side of longevity )
The key can be replaced or filed and the edges of the keyway on the shaft can also be be filed but there may still be some slight binding after filing.
Again, if it were mine I would bite the bullet.
Bill V

Thanks for all of the input Bill. You and I are alike in that I'd prefer to just fix it all the right way so that it will last and I don't have keep fighting with it over and over. I've gone ahead and "bitten the bullet" my way and ordered a whole new assembly including the shaft (since mine is old and worn and needs a good cleaning, but I also added in a new key, ring, and clip for my current one so I can fix it, clean everything up, and have it as a backup for a rainy day.

I greatly appreciate all of your and JPG's input, I'm thrilled to be a part of this community of woodworkers who I can glean as much from as possible!

[Teggy]

Thanks Bill and JPG for the quick responses. Here are the pics. The shaft key and my old control sheave key way are both 0.4 cm (4 tenths of a centimeter) and the NEW sheave key way is 0.3 cm (exactly 3 tenths of a centimeter) (Yes I know you guys are woodworkers and know how to measure but just making sure I'm being clear in my descriptions.

Shaft Key.jpg

Old Control Sheave Key way.jpg

New Control Sheave Key way.jpg

Is it my imagination or is the casting for the new sheave incomplete? It looks like there's some metal missing and maybe a small crack. I've never had one apart, so I may be imagining it.

Looks the same to me, the pics may be a little different because the 2 sheaves are backwards from each other in the pic. The old sheave had the bearing tear out so it was better to measure from 1 side whereas the new sheave was in tact so it was easier to measure/take pic from the other side.

[JPG]

Great thanks JPG! I'll post an update back here once I can get the parts in.
Do you know if there is a guide to replacing the key? Haven't ever seen one but I know you've posted a lot of how to's on here.

Well you have already got it started.

You will have two obstacles.

1) Getting the clip removed. It is down inside the idler sheave center and is small and not easy to grab with a pair of pliers. You may have to use a small screwdriver or 'pointed stick' to push the clip open(wishful thinking somewhat).

2) The fat key. The idler sheave must slide over it to get the sheave off the shaft. A file run down the sides of the key will help that. After looking at your pix of the shaft, I doubt you could inflict more damage than it already has.

The key has a 'crook' in the end that nests into a depression on the shaft at the end of the keyway under the sheave hub.

The sheave retains the key, and the clip retains the sheave.

If one were desperate enough, a key could be made from straight 1/8" key stock by bending that crook on the end. The deforming must be restricted to the end only. That makes it less than easy to 'make one'.

[wa2crk]

JPG
When the entire assembly is ordered from the factory isn't the sheave,retaining clip and the key, pre-assembled at the factory?
Bill V

[JPG]

JPG
When the entire assembly is ordered from the factory isn't the sheave,retaining clip and the key, pre-assembled at the factory?
Bill V

I assume so not ever having received one.

[Teggy]

JPG
When the entire assembly is ordered from the factory isn't the sheave,retaining clip and the key, pre-assembled at the factory?
Bill V

I assume so not ever having received one.

Yes of course it is! I got extras so I can fix my old one and have that as a backup.

[ChrisNeilan]

Just food for thought. I hate replacing keys. They never cooperate with me! In the past I have resorted to mildly heating the shaft (metal expands) to fit the key in. "Keyword" (sorry for the pun) is mildly heating!

[rpd]

(sorry for the pun)

Never be sorry for a pun.