Quote from: Steve1 on April 29, 2022, 10:28 AM

File it down.

Though contact the head maker before that - they may not be aware of the issue, or your head was wrong made etc. etc.

Once you file it, you cannot (safely) use the old head with that key, so the head maker should at a minimum compensate. Ideally shipping you a fixed head.
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Not planning on using the old head.  I'll check with manufacturer

According to JIS standards the dimensions for a 5 mm keyseat is 4.97-5.00 mm. While the Sheartak keyseat measures 4.90 mm, so as mino said, the issue is with the Sheartak product.

In the event that they do not offer the cutterhead shaft with a properly sized keyseat, I'd reduce the width of the key using a whetstone not a file. That way you can reduce the size of the key in small, repeatable increments. I'd also only trim one side of the key keeping the other side original/straight.

Quote from: festal on April 29, 2022, 02:52 PM

Yep reached out to them.  I checked mcmaster just in case and also saw that size of 5mm keys is undersized by -0.030mm to 0.000mm so sheartak is definitely out of spec.  Waiting for the engineers to get back to me.  Don't have a whetstone but I do have super fine dmt diamond stone.  Would that work?
Didn't know to remove it from one side only.  I was going to do both sides equally

The DMT stone is fine.

Trying to take equal amounts from both sides buys you nothing as there's no need to center this item...the key doesn't care. 

You're only going to remove .003"-.004" total from the key.

Just measure, take 4-5 strokes, remeasure and proceed until you're within .001" of where you need to be, then just take a stroke at a time and fit by hand.

It'll be interesting to hear why Sheartak didn't feel the need to follow a standard. 

Quote from: festal on April 29, 2022, 06:07 PM

Already in progress. Down to 4.95mm so far.

Heard back from sheartak

Alex,
It’s disappointing that you find the keyway is not wide enough for your key.
The keyway should be 5mm as on our print. We mill the keyway with a 5mm end mill.
I am wondering if there are burs on both sides. There are two ways to fix this.
Fill the both sides of the keyway. As the keyway is open, this can be easily done.
Grind the key a little bit. If you a bench vise, clamp it between the jaws. File both sides with a coarse file or grinding stone.
If you don’t want to bother, you can return it to us for full refund.
We apologize for all the inconvenience this issue has caused to you.


Sent from my iPhone using Tapatalk

That's interesting...having spent 40 years in engineering there's a major disconnect here with Sheartak internal QA/Engineering folks.

From a Quality Assurance standpoint you need to be absolutely certain that the products you're shipping are within specs. This guy's saying that the print calls for 5 mm and they use 5 mm end mills so it must be 5 mm, without being the least bit curious if it is or if it is not 5 mm. And by the way, just beaver it out with a file while you're at it...sorry for the inconvenience.

If I were the customer service person, I'd have asked to have the product returned and I'd immediately ship you a replacement part with 1-day service.

At this point Sheartak obviously doesn't care that there may be other cutter heads out there with keyseats that are not within their own declared specifications. And even if Sheartak isn't doing the actual keyseat machining, they still need to know about any dimensional discrepancies so they can work with their vendor to correct any issues. Yikes...

One more thing, the square key doesn't care which side the material is being removed form, the keyseat & the keyway DO care.

Quote from: festal on April 29, 2022, 07:34 PM

Yep annoying. Sorry to say but kind of typical response from Chinese vendor. No qc. Etc. they did offer return for full refund but it involves shipping it to Canada and taking it out since I already installed it . And  they didn’t offer advanced replacement. It was a funny response that print calls for 5mm and we used 5mm bit so it must be 5mm lol.   Wonder if anyone actually checked if end mill is 5mm or they forgot to compensate for tool wear

Anyways thank you for helping . I got it done and installed. Finale measurement ended up being 4.93mm. Fit perfectly with no play

Ya for those reasons you mentioned a manufacturer always needs to have the discrepant product in-hand.

Good for you, it looks good.    What did it take you on the DMT, 15 minutes or so? Fire it up and let us know how you like the upgrade.