Thread: Impero II: the cousin of parting tool

Michael I've never seen anything like that before. Apart from being able to be sharpened almost indefinitely, what's the idea behind that?

Hi Michael,
A very interesting tool, i really like the way the head can be rotated to match the helix angle of the thread being cut.

If your looking at making one, why not swap the splines for another taper? then the hardest part becomes making the blade itself and attaching it to its hub. If you do go down the road of making one i for one would be very interested in seeing how you go about it.

Cheers
Ew

Nup, I don't get it Michael ?

I would need a damned good sales pitch to buy that.

I reckon I can cut threads ok now so how would that make them better, cheaper or quicker ?

What is the reason for being able to angle the disc ?

It looks like it fell out of ET's tool box to me

Originally Posted by Michael G

The only way I can think of doing an internal spline that small is with a specially made broaching tool.

How about a shaper?
I've thought about making one but doubt I do enough threading really(though that wouldnt necessarily stop me lol). Wouldnt the straight type be easier to make?

Originally Posted by shedhappens

so how would that make them better, cheaper or quicker ?

The important grinding has been done for you. To resharpen you grind the top and you are good to go again.

Stuart

Originally Posted by Stustoys

How about a shaper?
I've thought about making one but doubt I do enough threading really(though that wouldnt necessarily stop me lol). Wouldnt the straight type be easier to make?


The important grinding has been done for you. To resharpen you grind the top and you are good to go again.

Stuart

Currently I spin a tip or touch up on the grinder anyway ?

What a great improvement on the originals.
It would have been real handy to be able to rotate the heads to suit the lead angle.
Screwcutting tools 006.jpg Screwcutting tools 004.jpg Screwcutting tools 005.jpg

Phil

Originally Posted by Pete F

Michael I've never seen anything like that before. Apart from being able to be sharpened almost indefinitely, what's the idea behind that?

Originally Posted by shedhappens

Nup, I don't get it Michael ?

I reckon I can cut threads ok now so how would that make them better, cheaper or quicker ?

What is the reason for being able to angle the disc ?

I see the advantages of a tool like this as being

• The head can rotate to match the thread helix angle - not critical for most threads but a nice touch
• The correct angle is produced on the lathe when producing the disc - better control & a more accurate angle
• Normally when I grind a tool off-hand I manage to over heat the corners so my ACME threads for example have radiused thread bases. A tool like this has more support for corners and because grinding is only on the top surface, less chance of over heating
• Easier to take threads closer to a shoulder
• Because it is HSS, breakneck speeds are not required
• You would be able to keep a box of cutters for all the thread forms and angles and swap them quickly rather than a selection of inserts or individual cutters

It may be mainly personal preference, but I like it

To make one I think I would press fit the stub into the disc but instead of upsetting/ swaging it over I'd probably TIG it in. The advantage of the spline over a taper would be that a taper could possibly slip whereas a spline will not.

Michael

Michael you have a shaper and a divider. Why is the spline a problem?

PS: I've forgotten what kind of tool post you have, but can't you make a holder to take the 25mm shank? Then you can borrow the boss's cutter.

Originally Posted by Michael G

To give an idea of scale, the disc is 53mm in diameter and the splined stud is 16mm. The only way I can think of doing an internal spline that small is with a specially made broaching tool. It would be a fiddly thing to produce.

Michael

Piece of cake if you have a vertical slotter. I've used mine to make 6mm square holes in replacement chuck jaw screws - I was showing Phil (Steamwhisperer) when he came to visit last year. A 16mm hole is heaps of room.

PDW

Originally Posted by Michael G

To make one I think I would press fit the stub into the disc but instead of upsetting/ swaging it over I'd probably TIG it in. The advantage of the spline over a taper would be that a taper could possibly slip whereas a spline will not.

Michael

53mm dia, this tool is designed for cutting large threads in large machines I suppose.

I think that Ueee's idea of the taper should not be brushed off, the way I'm looking at it is that when cutting threads you normally only take a series of smallish cut's so the load on the tool is fairly light and rarely are the cuts interrupted.

The disadvantage of the spline would be in the sharpening, I think you would need to use a flat faced diamond wheel, the side of a grinding wheel may work for a couple of sharpening's but then you would need to dress the side of the grinding wheel ? Most likely a jig to get the top rake correct would be warranted, if the jig was made so that the axis of the cutting tool could be inserted into it then you would be able to rotate the cutter into the wheel and regrind the top rake perfectly every time. But.....you have the 7.5 degree's of the spline to contend with, as you sharpen the cutter it cannot be rotated to the centre height and you will need to adjust the tool holder height until you get to the point where you need to go to the next spline where upon you will need to start from scratch and move the tool holder height down again. With the taper you would just rotate it to the centre height.

If you rotate the cutter sideways to suit the helix angle then the top rake also has to be adjusted to suit, I can't see why you would need to do that anyway ? All the relief you need is already there.

How much are the replacement cutters Michael ?

Originally Posted by Michael G

To make one I think I would press fit the stub into the disc but instead of upsetting/ swaging it over I'd probably TIG it in.

Michael

Michael these rods are pretty handy for welding HSS to mild or 4140

Cobalarc Toolcraft | BOC Australia

Hi Michael,

Do you have any specs on how big a thread this can cut?
It looks like it could cut at least 6mm(maybe more like 8mm) deep. Thats one large thread!\(well atleast it is for me, now if you were cutting worns that would be a little different )

Stuart

G'day Michael,
The tool you have shown is a fairly nice looking piece of kit.
Before you embark on having a crack at replicating it though, have you seen this type of tool before:

DTM H65 8A Lathe Threading Holder AXA Aloris T10 Insert | eBay

It slips straight onto an AXA holder (if you have one) and appears to have the same versatility as the one you pictured, helix angle adjustment etc.
From memory I'm pretty sure you can get blades for a number of different thread forms if you need them.

I think I've seen knock off versions of these too.
Cheers,
Greg.

Ok....I can see it now

large threads = low TPI = increased helix angle = less/no clearance on the face of the cutter

hence adjust for the helix with the cutter

DOH