Bushings for Coyote pen

[Bope]

I am trying to make my first Coyote pen from McKenzie and I am finding that bushings for other 3/8" tube pens will not fit. I don't buy bushings for every kit I make, I just look for bushings using the same tube diameter and as close as I can get to the final pen diameter. I turn close and then use calipers for final dimension. The tube seems to be about 0.004" too small for a 3/8" tube bushing. The IAP app shows the inner diameter similar to other 3/8" tubes. Anyone else have this problem?

 

[Darios]

To paraphrase :
Man with one set of digital calipers always has an accurate measurement. A man with two sets of digital calipers is never again certain.

Here's the measurements from my coyote bushings taken just now : 0.436 outer / 0.3385 inner / 0.471 outer.

FWIW the bushings just fits nicely with no problem on the tube that came in the kit and with some spare 3/8 tubes I got from PSI. Which is not what I would have expected from the measuring because 0.3385 is closer to 11/32 than it is 3/8s.

FWIW the outer measurements aligns closely with the outer dimensions posted on McKenzie's website :
Finished Lower Section Diameter: .440" and
Finished Top Finial Diameter: .476"

One thing is a lot of the measurements that go into the reference doc and the app are volunteer provided, each with likely differently calibrated tools. (I'm using an accumaster 7410 by the way)

Another possibility is that Mackenzie changed things with the Coyote from when Laserlinez had 'em and/or nobody has updated the core information in the database since then - the reference doc's latest update is in Jan 2021 - so there may be newer information on the app. But the doc shows the only Coyote pen being when it was with Laserlinez it was a twist pen (not a click) and the bushing sizes were even on both ends - 0.466 / 0.345 / 0.466

Or maybe the factory measurements were off when the instructions were printed.
Or the bushing manufacturer was having an off day on day the bushings you are using were created.
Or ... etc. etc.

All that being said, you might want to look to Amazon for a cheapy brass tube expander

 

[Curly]

The tube stock used to make the kit a likely US made and may have thicker walls than the imported kit tubes. The 3/8" size is not the actual brass size, usually the drill bit for the blank hole they fit into. That is the main reason for confusion regarding tubes.

 

[Bope]

I finally got around to doing more measuring. The ID of the coyote tube is smaller than the tubes for other pens that take a 3/8" hole. I took the coyote pen parts and they were a slip fit not a friction fit into the other pen tubes. Others that mix and match their bushings and pens note that the size of the coyote tubes is unique and require their own specific bushings.

 

[philipff]

To paraphrase :
Man with one set of digital calipers always has an accurate measurement. A man with two sets of digital calipers is never again certain.

Here's the measurements from my coyote bushings taken just now : 0.436 outer / 0.3385 inner / 0.471 outer.

FWIW the bushings just fits nicely with no problem on the tube that came in the kit and with some spare 3/8 tubes I got from PSI. Which is not what I would have expected from the measuring because 0.3385 is closer to 11/32 than it is 3/8s.

FWIW the outer measurements aligns closely with the outer dimensions posted on McKenzie's website :
Finished Lower Section Diameter: .440" and
Finished Top Finial Diameter: .476"

One thing is a lot of the measurements that go into the reference doc and the app are volunteer provided, each with likely differently calibrated tools. (I'm using an accumaster 7410 by the way)

Another possibility is that Mackenzie changed things with the Coyote from when Laserlinez had 'em and/or nobody has updated the core information in the database since then - the reference doc's latest update is in Jan 2021 - so there may be newer information on the app. But the doc shows the only Coyote pen being when it was with Laserlinez it was a twist pen (not a click) and the bushing sizes were even on both ends - 0.466 / 0.345 / 0.466

Or maybe the factory measurements were off when the instructions were printed.
Or the bushing manufacturer was having an off day on day the bushings you are using were created.
Or ... etc. etc.

All that being said, you might want to look to Amazon for a cheapy brass tube expander

I wholeheartedly agree with this method. All my bushings are in a junk pile waiting to be melted down. Philip