Tipped Tools

First off inserted tip tools are, in general and massively oversimplifying, designed and engineered to work best for fairly specific jobs under fairly specific conditions. This means industrial strength machines and, usually, CNC speeds and feeds. In particular they are mostly made to work on what can be called the back side of the spindle hp per unit volume of metal removed curve where going faster and working harder means you shift more metal per hp. Fine with full enclosure and mechanical chip conveyor but somewhat worrying with an open machine, especially in the home shop. Under industrial conditions each tip edge usually lasts only a few hours, often less, but the amount of metal shifted in that time is impressive.

At home its much more comfortable to work at relatively low metal removal rates, on the front side of the curve where hp needed goes up faster than metal removal rate. HSS tooling works fine in this region. The general run of Model Engineer machines have neither the strength, speed or power to drive industrial rated tip tooling into their design operating range hence the perception, in some Model Engineering circles, of tipped tooling being inferior to HSS. If you insist on using something outside its design operating range poor performance should be no surprise so its only to be expected that a randomly chosen insert will not give of its best.

There are approximately a zillion different types of insert out there. All the major makers produce lots of data enabling the informed purchaser to select a decent insert for the job. All that data and choice is a major, major headache for the normal guy. Best answer is to go to a specialist, such as Greenwood Tools, who will be able to advise you on a suitable style and grade of insert that will work well on your machine. At home you will almost certainly be running the insert outside its design envelope but it will last a lot longer. I understand you now have a Smart & Brown model A which makes life far easier as you have decent speed and strength so could run some inserts to their design loading.

The RDG tools sets look nice in the catalogue but I don't know how well they are made. Proper location of inserts is essential or they will break quite easily. Also I see no specifications as to maker, material and detail shapes of the supplied inserts nor any details of speeds and feeds. All vital information. I personally would not deal with a firm so unprofessional that they cannot be bothered to supply such. A bit better than the no-name E-Bay cheapies who don't even know the type of insert, assuming its a standard that is. One such supplier not only offered non standard inserts but was unable to provide replacements!

Parting tools are much easier. Just buy one of reputable make. Mine is a Kennametal with 3 mm wide inserts.

In my view best bang per buck in the home shop lathe tooling is HSS bits in properly used Armstrong / Williams / J&S (best) holders along with a decent size grinding table and nice set of templates so that you always sharpen to the same angle. Proper use of the tool holder means that, except for the occasional difficult job, the shank of the toolbit is either at 90° to the lathe axis (normal turning) or parallel to it (facing). The holders are bent to facilitate this. If you have a simple tool height gauge its easy to leave the holder mounted and interchange bits as a very poor mans QC system.

Clive

Edited By Clive Foster on 29/11/2011 22:35:21

Posted by Wolfie on 29/11/2011 21:12:57:

OK I need to buy a boring tool and I'm looking at RDGs selection of tipped tools.

 

First off, are tipped tools any good, I have been told that they are inferior to ground HSS tools? (My ground HSS parting tool broke )..........................

 

Edited By Terryd on 30/11/2011 05:54:35

Edited By ady on 30/11/2011 08:15:14

(My ground HSS parting tool broke )

Edited By ady on 30/11/2011 08:22:23

It only has two wheels like any other and one is a wire wheel and the other is a fairly fine stone which is taking ages and ages to remove metal from HSS.

 

Yes I know I could change the wheels over each time but thats a big hassle as well for two reasons. One is that I have to dismantle the whole guards set up to get at the nuts at each end of the spindle.

 

And secondly and far more of a pain is that for some insane reason I can't hold the wheel at the other end so I can do the nut up,  because if I do it undoes the nut at its end (opposite threads???) and I struggle to get either of them done up properly. There doesn't appear to be another way of holding the spindle so I can do the nuts up

 

Edited By Wolfie on 30/11/2011 11:08:45

Posted by Wolfie on 30/11/2011 11:04:08:

 

..................................

 

And secondly and far more of a pain is that for some insane reason I can't hold the wheel at the other end so I can do the nut up, because if I do it undoes the nut at its end (opposite threads???) and I struggle to get either of them done up properly. There doesn't appear to be another way of holding the spindle so I can do the nuts up

Edited By Wolfie on 30/11/2011 11:08:45

Edited By Terryd on 30/11/2011 14:55:06