Key on spindle to high

[mattsutton29]

Hi can anyone give me some advice. Just changed the motor in my woodfast m910. It came secondhand with a 1hp motor. Which is underpowered for my work. I’ve bought a 2hp tec motor and inverter from newton tesla in Warrington. Great company. Only problem is the spindle is 24mm which is fine, and the key is 8mm wide which is fine. But the key height is twice that of the key way in the pulley. What do people recommend. I’ve thought about trying to grind it down to the right height but I’m not jumping in just yet.

 

[Andy's Shed]

Filing it down would be my move.

 

[Distinterior]

They are not expensive to buy. Various sizes & specification here.......
https://www.accu.co.uk/893-parallel-keys?Height+(H)=7mm&Width+(B)=8mm&page=1

 

[mattsutton29]

Thanks guys. If I were to get a new key how do I remove it?

 

[Fergie 307]

If it's a half round Woodruff type then tapping gently on one end should lift the other end up so you can pull it out. Probably easier to just file it down in situ.

 

[ChaiLatte]

They are not expensive to buy. Various sizes & specification here.......

For the page to which you link, the 8mm wide keys are available in only one height, 7mm. The only variable is the length.

A standard key is made to a standard width and height. Please could you find and post a link to an 8mm wide one in less than 7mm high, otherwise you risk sending the OP off looking for a unicorn.

---

To the OP: rather than taking a file to your key, you should be asking yourself why the keyway in the pulley is too shallow and remedying that part of the problem.

Standard metric keyway dimensions are here: Keyway Chart

For a 24mm shaft with an 8 x 7 key, it should project approx. 3mm. Your statement "the key height is twice that of the key way in the pulley" thus implies the keyway in the pulley is only 1.5mm deep. Do you think that is sufficient to transmit the full 1.5kW of power your new motor can deliver?

Returning to your question:

The most likely alternative key (it would be quite unusual for a motor to be supplied with a Woodruff key) is a parallel key. Grip it on the sides with a pair of pincers, wiggle it a bit and it should come out. Grip it hard and you can use a screwdriver under the pincer jaw to prise it out.

It is far easier to file it down when gripped level in a vise than when it is still attached to a motor shaft that can rotate and has a large lump of its body in the way.

You can remove it with side cutters gripping the end, but that is a bit brutal and can raise burrs on the end of the key.

If you have an appropriate wedge, you can insert it between the motor end of the key and the motor body and ease it towards the open end of the shaft. It helps to clamp the wedge lightly to the motor shaft.

 

[Distinterior]

..... Please could you find and post a link to an 8mm wide one in less than 7mm high, otherwise you risk sending the OP off looking for a unicorn....

Well,...I do apologise!
After all, I was only trying to help!

Perhaps you could "find and post a link" to a suitable replacement...?

 

[ChaiLatte]

Perhaps you could "find and post a link" to a suitable replacement...?

There isn't one. And that is my point. Had you posted a page with a selection of 8mm wide keys of various heights, it would have been both helpful and relevant to the question.

Attempting to be helpful is always to be applauded, but doing so without first either knowing or verifying that the helpful thing you suggest actually exists is counterproductive, especially if the person asking the question is inexperienced.

 

[Phill05]

Hi can anyone give me some advice. Just changed the motor in my woodfast m910. It came secondhand with a 1hp motor. Which is underpowered for my work. I’ve bought a 2hp tec motor and inverter from newton tesla in Warrington. Great company. Only problem is the spindle is 24mm which is fine, and the key is 8mm wide which is fine. But the key height is twice that of the key way in the pulley. What do people recommend. I’ve thought about trying to grind it down to the right height but I’m not jumping in just yet.

Mat, any chance of an image to show what is needed please, from what you say it sounds like the problem is the keyway in your pulley has not been cut deep enough.

 

[Distinterior]

There isn't one. And that is my point. Had you posted a page with a selection of 8mm wide keys of various heights, it would have been both helpful and relevant to the question.

Attempting to be helpful is always to be applauded, but doing so without first either knowing or verifying that the helpful thing you suggest actually exists is counterproductive, especially if the person asking the question is inexperienced.

I dont think the OP stipulated a height of the key in his post......How do you know 7mm height isn't the size he actually requires.?

I'm not looking to start an argument with you ChaiLatte, but you do come across as trying to do so.

I'll drop out of this thread now.

Good luck Matt, hope you manage to find what you're looking for.

 

[mattsutton29]

Hi everyone thanks for all your help. I ground it down with an angle grinder then a file. The keyway could not be any deeper. As shown in the photo of the new damaged pulley sent by record power on Friday. Which hopefully they will rectify when I ring and complain tomorrow.

 

[mattsutton29]

Pics of pulley

 

[Fergie 307]

For the page to which you link, the 8mm wide keys are available in only one height, 7mm. The only variable is the length.

A standard key is made to a standard width and height. Please could you find and post a link to an 8mm wide one in less than 7mm high, otherwise you risk sending the OP off looking for a unicorn.

---

To the OP: rather than taking a file to your key, you should be asking yourself why the keyway in the pulley is too shallow and remedying that part of the problem.

Standard metric keyway dimensions are here: Keyway Chart

For a 24mm shaft with an 8 x 7 key, it should project approx. 3mm. Your statement "the key height is twice that of the key way in the pulley" thus implies the keyway in the pulley is only 1.5mm deep. Do you think that is sufficient to transmit the full 1.5kW of power your new motor can deliver?

Returning to your question:

The most likely alternative key (it would be quite unusual for a motor to be supplied with a Woodruff key) is a parallel key. Grip it on the sides with a pair of pincers, wiggle it a bit and it should come out. Grip it hard and you can use a screwdriver under the pincer jaw to prise it out.

It is far easier to file it down when gripped level in a vise than when it is still attached to a motor shaft that can rotate and has a large lump of its body in the way.

You can remove it with side cutters gripping the end, but that is a bit brutal and can raise burrs on the end of the key.

If you have an appropriate wedge, you can insert it between the motor end of the key and the motor body and ease it towards the open end of the shaft. It helps to clamp the wedge lightly to the motor shaft.

Why would you assume that the manufacturer would make the part with too shallow a keyeay, they presumably have some idea what they are doing and will have used a key size suitable for the job. Not just dependent on load, but also the msterial used and what the key is actually doing. In many cases the key merely locates the pulley in a particular position, to preserve balance or for timing purposes, and does not actually retain it, or bear any rotational load at all. It is often the case that you will encounter different key dimensions, for instance when replacing an old imperial motor with a modern one with metric dimensions.

 

[Phil Pascoe]

There's not actually much metal between the keyway and the thread, is there?

 

[Fergie 307]

Presumably why they used a lower profile key.

 

[Spectric]

Why not apply some basic engineering and dress the key to suit, they are not hardened and easily dressed with a fine file so as you can reduce the height so it can be inserted.