Here lately I have been having a tough go reaming cork grips. I am using a Batson dream reamer with a power drill.
Starting out small and working my way up to the desired diameter and come to find that one end is out of center. I have
tried drilling a little and turning the grip 90 degrees every so often. Still not working. Ruining cork and hurting the wallet.
What am I doing wrong? These are split casting and spinning grips, not full. Need tips and help!

It's hard to keep the bore concentric by hand or drill. The key is to keep moving up in reamer size. You want to the reamer making contact around the entire ID of the grip bore as you push the reamer into the grip. You do not want to simply move the reamer against one side of the bore. It must make contact all the way around. Once it no longer does that, you move up to the next larger diameter reamer.

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When reaming a grip it’s important to let the grip slip in your hand. I put the grip on the reamer and just pulse grab the grip while turning. By pulse grabbing I mean I just grab the grip while it turning on the reamer for about a second or so, this allows the grip to reposition keeping the hole concentric. If you just grab the grip and hold it so the grip doesn’t rotate while reaming, you are almost guaranteed that the hole will not be concentric. When hand reaming turn both the grip and the reamer. Also the FlexCoat reverse pilot bit, and arbor pilot bits work extremely well for keeping the hole concentric. Final reaming can then be done with the Dream reamer.
Norm

I have the same issues, although doing what Norm suggests about letting it slip in your hand does help.

In an effort to combat this issue, I just ordered some Flex Coat Arbor Pilot Bits and Reverse Pilot Drill Bits from Voodoorods.com that Norm mentioned:

[voodoorods.com]

[voodoorods.com]

These Bits use the predrilled holes in the grips as guides to ensure the bit stays centered.



Edited 1 time(s). Last edit at 01/19/2024 11:59AM by Patrick Coco.

Why don't you guys consider using indivual cork rings mounted directly on the blank - then shaping on cork lathe - like FlexCoat's.
Herb

With the smaller reamer, ream both ends of the grip half way. Then send that reamer all the way through from the bottom. And always do what Tom and Norm suggest.

The reverse pilot bits are among the most helpful tools a rod builder can have.

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Have you tried reaming by hand and see if you get a better result?

Amen to what Norman and Tom said about the reverse pilot bits from Flex Coat. I started making my own cork grips a couple of years ago and had the same problem of slightly off center bores. As Norman said, pulse grabbing the grip helps quite a bit. But when you can bore the hole a lot closer to the OD of the rod blank, it makes the reaming process sooooo much better.

I found that boring my cork rings so they have a .375" bore works best for me. Most of the blanks I work with are slightly larger than .5" so I use a 1/2 reverse pilot bit and wrap the shaft with masking tape to build up parts of it to 3/8". I bore from both ends of the grip. I go about half way from one end, and then complete the bore from the other. That way if there is any little deviation from where the two bores meet. it isn't visible.

BTW, the total length of the shank on the reverse pilot bit is 13 1/2" so figure after you chuck it up in a drill, you can bore a grip up to 13" in length. They're awesome!!!

Oh and I just picked up one of the pilot bits from Flex coat. It's going to work great for boring out foam arbors.

Flex Coat had some great ideas when they came up with these bits.