drilling rubber bumper

[dendweller]

I saw a post from a while ago about putting the bumper in the freezer overnight and drilling it for an extension.
I gave it a try and was surprised it mostly worked. Wouldn't get through the last 1/8 inch, probably thawed by then, I just cut that slice off and worked well.

Wondered what others are doing, I drilled this for 7/16. Looks like unique has them at 3/8th. Actually, that's probably what I got from that 3/16th bit. Maybe I'll order a bag of those and see.

Thanks

 

[Sheldon]

If you "drill" them with live tooling in your lathe you might have better results.

 

[ldmitchell]

Here is what worked for me when I needed to make a hole in a bumper for an extension.
I made a hole cutter out of an empty 30:06 rifle shell. I cut the shell at the diameter I needed, held the shell in the tailstock drill chuck and bumper in the lathe chuck.
It made a nice neat hole. Used a little water for lube.
Leonard

 

[Ssonerai]

Not sure i really am clear on the question?

I use the type of bumper that has a 3/8"-16 threaded projection.
OTOH, I have shaped them OD & use a surface grinder and spindex, no freezing.

Have also drilled rubber plugs in a collet with relatively fast speed, small feed; however if i wanted it to look good would probably use the highspeed attachment with a grinding bob in the tool and cutter grinder. I do use water base mist or coolant when shaping rubber on the grinders.

There's also a drawer full of rubber plug cutters here made from tubes of various sizes and materials, by turning a sharp edge on it in the lathe, and using like Leonard describes. (Though have not specifically used a munitions shell yet )

 

[dendweller]

Not sure i really am clear on the question?

Here's what I'm after, this is the one I did by freezing. Seemed like it must of thawed by the time I got to the back, it just stretched so I cut the back off with a razor.

 

[dendweller]

Here is what worked for me when I needed to make a hole in a bumper for an extension.
I made a hole cutter out of an empty 30:06 rifle shell. I cut the shell at the diameter I needed, held the shell in the tailstock drill chuck and bumper in the lathe chuck.
It made a nice neat hole. Used a little water for lube.
Leonard

Thanks, that does sound like it would make a neat hole.

 

[Sheldon]

So are these suggestions about having a dremel or router on the carriage? Sorry if it's a silly question.

Yeah, I have some Porter Cable laminate trimmers set up on quick change tool holders. I did a few extensions making my own inserts and drilling/trimming bumpers at first. I used a 1/4" end mill in the router.
I've been using these for a while now.

Tap a piece of phenolic for an insert, then chuck up on the tap for your final pass for the OD on the insert. Glue that in and now you have a nice removable extension bumper.

 

[Ssonerai]

Here's what I'm after...

OK, i was a little slow on the uptake.
Sheldon gave a better answer.

However, ID/OD grinding is not a bad set of options to have in your cue-making tool kit.
I have found with tough problems with flexible materials and some multi-piece metallic inlays, that grinding (& patience) can sometimes be the only solution. Gotta watch the heat, though, esp with the metal inlays. They will swell and de-bond.

 

[dendweller]

OK, i was a little slow on the uptake.
Sheldon gave a better answer.

However, ID/OD grinding is not a bad set of options to have in your cue-making tool kit.
I have found with tough problems with flexible materials and some multi-piece metallic inlays, that grinding (& patience) can sometimes be the only solution. Gotta watch the heat, though, esp with the metal inlays. They will swell and de-bond.

Kinda funny how it worked out. I had quite a few of those bumpers around. One batch was pretty stiff, the other was soft. I didn't like the stiff ones much harder to put on, take off etc.
The stiff ones, you could just chuck up and drill. It wouldn't go through the back, once it was a thin layer it just stretched, but it was easy enough to just slice off the 16th of and inch at the bottom. The soft ones acted like rubber. Now I like the stiff rubber better.