Next Project Boring Head

Two things that I am wondering about. One is what size boring bars should I drill the holes in the head for? I don't have any metric drills and my imperial drills are in 1/64 increments. I am leaning towards 1/2" boring bars. Other choices under consideration are 3/8, 10 mm & 12 mm.

You might consider making your boring bar holes as large as is feasible, which gives you the flexibility to sleeve for smaller diameter bars. The boring head I use has 1/2" holes, and so far I have made sleeves for 1/4", 6mm, 7mm, 8mm, and 10mm boring (and threading) bars.
 
That sounds like a good suggestion. Right now I have the holes at 1/2." I could go maybe as large a 3/4." Is it important for any reason to have the inner hole centered in the head?
 
The only changes I made to the original plan were reducing the drive shank to 3/4"
and using a piece of round bronze for the adjusting nut instead of a small steel rectangle, also went to 1/2" boring bar holes instead of 3/8".
The plan is solid for use as written keeping it centered is crucial to me for adjustment YMMV ...........................:cool:
 
Need some help. I have never used a dovetail cutter. Don't own one and have never even seen one except in pictures. They are not expensive but not cheap either. I am thinking about buying a couple. My problem is what size do I need to buy to cut a 60 degree dovetail that is 3/8" high and goes in around 3/16." I have searched the web for the sizes of dovetail cutters. Based on what I found I would need a 1" dovetail. That seems pretty big to me. Are these made to standard dimensions? Or is every manufacturer different? Help me out.
 
Mickri:

I bought a 60deg X 25mm HSS dovetail cutter from Banggood for $9.99 to cut dovetails for some AXA tool holders. It worked great and is still sharp.

I have had good experience with Bangood's Chinese HSS dovetail cutters, as well as with their carbide end mills. Here is the selection of dovetail cutters they offer, including a table with specific dimensions. You can see from their sizing chart that the 25mm cutter will cut a dovetail 10mm deep, which is just over the 3/8" that you need.

Unfortunately, you will need a way to hold these cutters, all of which are metric. Since I have a number of their carbide end mills as well as their dovertail cutters, I invested in a set of metric R-8 collets to hold them.

HTH, Bill
 
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I use metric ER32 collets in the mill/drill so metric isn't a problem. And 25mm is basically a 1" cutter which is what I had found as the size I needed in my research. Thanks for the use report.
 
I’m not seeing how you’ll adjust the head. The head of screw is usually cut into top and bottom pieces then the head is grooved to interlock with I believe top portion. Bottom has a ear on it to engage the screw so it has two flat surfaces. Or flip flopped. Just a thought.
 
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