How irritating

I’m thinking yet again it’s time to get a boring head and saw this, but it’s got a 3/8 Whitworth draw bar.

**LINK**

I use M12 on my mill.

This will ease your frustration go to another supplier that sells the 50mm heads with a choice of Arbors to suit your machine. Bonus is it will also save you some money

Thanks Jason, I’ll have a look. I went to Axminster first as I was hoping they still had a sale on.

Edit: anyone have any experience of this particular SOBA?

**LINK**

The Arc one looks good but it comes with carbide cutters and I don’t have a green grit wheel to sharpen them. I was hoping to use HSS as included with the SOBA. Any comments/advice on cutters much appreciated as I’ve never used a boring head before.

I have a very similar model to the Arc one, (NOT supplied by them I might add! ) and find it good, but the brazed carbide cutters not so. They seem to blunt fairly easily and the tips chip just by looking at them (in reality, probably more to do with my ham-fisted technique more than anything), but the size of the carbide tip leaves little material to sharpen afterwards

I'm assuming that all these models are made in the same 1 or 2 far east factories.

So, overall, not my best purchase

regards Mike

I bought a Soba about 15yrs ago from Chronos and it's fine and the one I usually reach for. Had the ARC one since I did the Milling for beginners Series and can't tell the difference, tend to keep this with the R8 arbor on it for occasional use on the SX2.7 though arbors are interchangable.

The carbide supplied really only needs a touch up with a diamond slip unless you want to start modifying the shapes for things like external work. I almost always use an insert bar in mine, Set of three Glanze ones via Chronos.

One other thing to bear in mind is that 2" heads tend to take 1/2" tooling and the 50mm ones 12mm or 1/2" depending on source so think ahead of what you might want to use with it.

I suspect the Axi one is actually 2" as it takes 1/2" tools and has imperial scale

Edited By JasonB on 31/08/2023 11:06:22

I modify M12 drawbar fittings by loctiting in a short piece of M12 studding.

The studding is then drilled and tapped 3/8 BSW.

If you try to drill / tap the studding first of all, out of nthe arbor, the wall is so thin that it tears. But in the arbor, it is supported and can be modified without problems.

Howard

Thanks for the comments folks. I want a metric one that takes 12mm tooling and a 12mm draw bar.

When I first got my mill, one tool holder had an 3/8 Whitworth thread so I had to buy a suitable die to make a draw bar. I then decided to go all M12 and re tapped the tool M12. No idea were the old draw bar went, I probably used it as stock for a project.

Chronos advertise various ones here:

**LINK**

I bought a Vertex 50mm-MT4 and had a choice of any arbour I want, Straight, R8 or any morse taper.

I clamped a 6mm Iscar small boring bar(It has squared sides) in its 12mm hole, adjust it's centre using the boring bar insert tip as a guide 1st outside then inside the hole with mill switched off, turn spindlec with hand, and to my surprise it bored just fine, no problems with quil going up or down, light cuts.

That’s interesting Chris, thanks for that.

I ended up getting this one from RTG:

**LINK**

I was going to get a 50mm but I experience a lack of Z height on my mill sometimes and this one seemed quite compact. I paid the extra £12 for the set that included 9 carbide tool bits but I’ll probably grind some HSS bits at some point. I already have a few insert boring bars as well.

Vic, you can make a simple holder for small HSS bits from a bit of 12mm dia bar cross drilled for the tool and tapped up the end for a grub screw to hold it. OK for through holes and saves having to grind 12mm HSS blanks and worry about clearance. Use old Ctr drills etc as the toolbits

Hi Jason, thanks. I was thinking just that earlier. In fact I have a tool just like that somewhere but I’m not sure what size the shank is. One end of the tool has a 90° cross hole and the other end is at 45°.