08-26-2013, 11:17 PM
I looked up Geometric and Rubometric and yep same basic idea, in most Commonwealth countries it was all Herbert and Ward , to my knowledge the Rigid pipe threading heads on the other hand were pretty universal.
As far as the difficulty setting up pitch circle... I can't say that I agree, the Herbert system has a little scale on the side, you simply turn the knob to set the cutters almost like jaws of a self centering chuck set to the centre mark for mild steel normal fit tighter for hard materials looser for soft and so on,
Theres not a lot of point setting up the head for just one thread but any more than two or three and the time saving is worth it, of course expect to run a couple of tests to get it set up right, but that is production tool setting. If you are as lucky as I am and have enough to set them all up to all your common threads and materials it really is just like using a die holder with the automatic function meaning you can thread right up to a shoulder, I even have some cutters custom ground "plug tap style" so you can thread ultra close to a shoulder.
Unlike the Rigid head these ones use purpose ground cutters, so even if the pitch is the same, a different diameter will mean different cutters.
The other difference to a Rigid head is that not all Rigids have the automatic function, where to my knowledge all Herberts do.
And yes I still use these, I have an exhaustive range of cutters mostly "BA" and some smaller Pipe sizes but one set of Metrics M8 from memory and of course 0BA is also M6. I have to find it... but somewhere... I have a 3MT adaptor I wasn't able to locate it for the photo, I also have a small range of Box tools. I had loads back in Aus but they didn't make the trip, nor did my Mint condition Ward No 3a turret lathe with the lever operated collet chuck with hundreds of collets including square and hex bar stock ones for pretty much all common sizes, I had loads of box tools in that size but... whatever... move countries and some stuff stays behind.
One day I'll get around to making a turret head for one of my lathes they are just so much fun for little production runs, but for now it's just the single holder mounted in the tailstock.
Regards
Rick
PS Mr Shipto, I might need to get to know you
As far as the difficulty setting up pitch circle... I can't say that I agree, the Herbert system has a little scale on the side, you simply turn the knob to set the cutters almost like jaws of a self centering chuck set to the centre mark for mild steel normal fit tighter for hard materials looser for soft and so on,
Theres not a lot of point setting up the head for just one thread but any more than two or three and the time saving is worth it, of course expect to run a couple of tests to get it set up right, but that is production tool setting. If you are as lucky as I am and have enough to set them all up to all your common threads and materials it really is just like using a die holder with the automatic function meaning you can thread right up to a shoulder, I even have some cutters custom ground "plug tap style" so you can thread ultra close to a shoulder.
Unlike the Rigid head these ones use purpose ground cutters, so even if the pitch is the same, a different diameter will mean different cutters.
The other difference to a Rigid head is that not all Rigids have the automatic function, where to my knowledge all Herberts do.
And yes I still use these, I have an exhaustive range of cutters mostly "BA" and some smaller Pipe sizes but one set of Metrics M8 from memory and of course 0BA is also M6. I have to find it... but somewhere... I have a 3MT adaptor I wasn't able to locate it for the photo, I also have a small range of Box tools. I had loads back in Aus but they didn't make the trip, nor did my Mint condition Ward No 3a turret lathe with the lever operated collet chuck with hundreds of collets including square and hex bar stock ones for pretty much all common sizes, I had loads of box tools in that size but... whatever... move countries and some stuff stays behind.
One day I'll get around to making a turret head for one of my lathes they are just so much fun for little production runs, but for now it's just the single holder mounted in the tailstock.
Regards
Rick
PS Mr Shipto, I might need to get to know you
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