Grinding small boring bars

[banksy512]

Because the commonly available insert boring bars never seem to go small enough for the size projects I build, I got some square 5C collets to grind the square tool bits round on the end on the D bit grinder and then create a boring bar cutting edge. I made a couple of sizes and seems to work a treat.

[oldnorton]

Yes, make your own small boring bars - I like seeing that.

I recognise the small, commercial tool grinding machine. Please remind me of its trade name.

Norm

[banksy512]

Apr 25, 2024 16:55:36 GMT oldnorton said:

Yes, make your own small boring bars - I like seeing that.

I recognise the small, commercial tool grinding machine. Please remind me of its trade name.

Norm

D bit grinder - they are also excellent for grinding lathe tools. It came with an attachment for grinding lathe tools but the square 5C collets work well for that as well.

I have not tried it yet but I think it would be great for grinding a small trepaning tool.

[johnd]

Great idea, I recently acquired an identical grinder cheaply from fleabay.
It did include some square collets so the boring bars will be one of the first projects.
I dont suppose if you have found a supplier of the grinding wheel spindle adapters?
Mine came with half a dozen assorted wheels but only one adapter.
Thanks for the inspiration.

[banksy512]

Apr 28, 2024 10:44:11 GMT johnd said:

Great idea, I recently acquired an identical grinder cheaply from fleabay.
It did include some square collets so the boring bars will be one of the first projects.
I dont suppose if you have found a supplier of the grinding wheel spindle adapters?
Mine came with half a dozen assorted wheels but only one adapter.
Thanks for the inspiration.

I have only used the one wheel on it so far and I have not found a need as yet 

[johan]

Last time I needed a small "boring bar" I used the remaining edge of a 6mm 2 flute mill. Worked fine. But I since got a small boring bar with inserts:

[pault]

You can get solid carbide boring bars at a reasonable price. Google Micro Boring bar

Have a look at
www.shop-apt.co.uk/miniature-carbide-boring-bars.html