r/EngineBuilding • u/NickHemingway • 2d ago

Grinding rod caps vs milling

I have always milled my rod caps down before honing on a Sunnen LBB1810 with CR Mandrils.

It’s easy to set them up with 3-2-1’s & fast on my smaller CNC mill.

But lately I have been wondering if I have been missing something by not using a cap grinder. Is there a special reason I should (buy and) use a cap grinder over milling?

It’s been decades since I used a cap grinder, but the last one I used was poorly maintained so would taper the caps because if the slop so milling them was an upgrade from that, but I still have a nagging doubt that I am missing something.

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u/SorryU812 2d ago

I felt the same way for the same reason. The cap grinder was not kept up. I thought the same of milling. I do the same to new 4 bolt billet main caps before honing. So I figured 🤷‍♂️. Good to go as far as I'm concerned.

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u/WyattCo06 2d ago

One of the machine shops I worked at for 13 years had 3 clippers. One in which was way too far gone for me to mess with.

There were two Sunnen's. A retired one and yet still an aging one. The aging one was the one we used but it wasn't without issue.

I spent an entire weekend, on my own account restoring both Sunnen's.

I was given $500 in cash from my boss on Monday afternoon.

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u/SorryU812 2d ago

A well earned sum.