i figured i would go ahead and lap the rings on my rifle. i've got a man at work that i can get to make me a lapping bar but is there anything special about them. I need one for 30mm rings. what does 30mm measure? Is there any thing special I need to know about. Is it just a solid bar or does it have groves cut into it. I've seen some with groves cut into it i guess it's just to help hold compound

Don't know the answers, but I have opinions.
I have a 1" bar and have lapped all my rings for years.
I bought a commercial model.
I would think that the bar would need to be hardened steel or it would wear "too small" quickly.

1.181

quote:

Originally posted by ted thorn:
1.181

Yep

quote:

I would think that the bar would need to be hardened steel or it would wear "too small" quickly.

Seems logical but that's incorrect. Fact is, the lapping compound will embed in the softer surface and then cut the harder.

My "lapping bar" is a 1" hardwood dowel I charge with Clover Brand valve grinding compound; it has worked great for some 15 years. I have never worked on 30mm rings but IF I needed to I'd lathe turn a dowel to 1.181" an go to work.

A "proper" lapping bar would be made of cast iron. Before you have one made measure the diameter of several scopes.
Then buy Burris signature rings with the polymer spherical inserts and forget the lapping business.

All of mine have been CRS

Well as long as the bar is softer then the steel ring. I know Leupold uses 12L14 for there bases I don't believe they use that for there rings though.

The lap need to be soft. And I would take a piece of CRS and anneal it then normalize Just for GP.

+1 SR4759 Hit the nail on the head!

God Bless, Louis

sounds great i'll get one turned down to 1.181 and give it a try. what grit lapping compound do i need to use. i've got plenty at work to choose from it seems a shame to go and buy some when my company wants to help me out. lol

Just plain ole Valve Lapping compound in fine grit works for my use.

I turn down old cast iron window weights, works just fine. Best to use someone else’s lathe for that. I only lap the bottoms and it only adds a few minuets to the job. If it helps or not? Duno, but it hasn’t hurt yet. Earl.

220.....and this is my lapp

I like that setup.
Thanks for the pics, that explains everything

Ted, other than a wood lap, your's looks like mine.

Well, my drill is DeWalt yellow. And my 'drive shaft' is 16" of moderately stiff outboard boat steering cable to permit easier alignment in the rings but the principle is the same.