What are these?

They look like knurls, but they could be intended to be used for other purposes. It's not apparent to me if they are typical/conventional type knurls or possibly the cutting type.

All of the knurls intended for metalworking that I've seen, IIRC, are supported at both sides by a holder because of the high force required to displace the material of the workpiece (for conventional type knurls).

I don't recognize the company logo of a W inside a diamond, or the A.B.T.C? on the other one.

I think it's likely that these pieces were used as knurls with the home shop made tool holder, but pressing knurls into metal workpieces requires a lot of force, and would be somewhat abusive to use them on a small precision machine.

There are scissor type knurling tools that don't require force from the cross feed to knurl a workpiece. They have a screw between the two floating knurl-holder arms, which is tightened to apply force to the knurls. The stress of knurling is maintained within the parts of the knurling tool, and not applied to the lathe parts.

Not just knurling, but decorative knurling with those grooves. Yes, you just press them, not move them along the workpiece as you would with normal knurls.

Probably for use in gold watch cases and the like.

Enjoy, DoN.

This is more along the lines I was thinking of.. decorative embossing of softer and/or thinner materials.

Thanks.

I have gone through the auction loot for the umpteenth time (on this occasion with a view of adapting the tiny little QCTP to my Taig - see

those interested - hardly a moon rocket!). Every time I look I find something new I did not appreciate before.

Being parallel to the axis of rotation - I don't think Knurling myself.

I think crimping wheels - put a wiggle edge on metal to splice and solder or just make stronger.

I have a large set - 4" wide and 2-3" in diameter.

Mart>

[ ... ]

One feature which is missing is a stop on each tool holder which can be adjusted so every time you drop it on the toolpost it is at the same height. Normally it consists of a threaded stud projecting upwards from the tool holder with a knurled nut on that to engage the top of the toolpost, and a smaller standard hex nut to lock it in place. Each tool goes in its own holder and is preset for height, so when you swap tools during a project, you don't have to keep adjusting the height every time you change.

Note, BTW, that the tool you have in the photos is probably a bit of an overload for the Taig -- a large radius round nose tool. You want something with a much smaller radius for most cutting, so you don't load the motor down so much.

Enjoy, DoN.

Especially as each toolholder has slightly different dimension :-)

I saw the stops on the commercially available QCTP from the Little Machine Shop and on several that people made themselves from scratch. In all honesty the person who made *this* toolpost did not think things through. Even I know enough now not to design it that way. However...it's there. The best I can say is that I can use the 10 or so 3/16 toolbits which I could have done before only with a lot of shimming. I cannot see myself adding the stops to all 15 or so toolholders. I would rather design something from scratch, allowing me to have a handle at the top of the QCTP and the ability to attach at least two toolholders at the same time as well as the stops etc. etc. (I think the originator thought he would attach 4 toolholders at the same time - in its present form the toolpost does not allow this.) OTOH come to think of it each toolholder has 3 set-screws so maybe I can draft the middle one for this duty (or replace it by a suitable post).

Or I can splash $100 on the commercially available QCTP. I understand that the toolholders that come with it include one for parting tools although the details are sketchy. Parting has been a major problem - the only parting tool I have has been ground at a slight angle from a 1/4 toolbit so it binds and chatters terribly. I have not got around to grinding another one.

I only put it in the holder to measure the height - the top of the round nose is nice and flat and when fiddling with the gauge etc. less likely to draw blood.

>> for those interested - hardly a moon rocket!).

:-)

Note that the toolposts like the Aloris and clones thereof may have two stations -- but they are not intended to have both stations loaded at the same time. One is for turning (tool is at right angles to the axis for turning along the length of the workpiece), and the other for boring and facing (tool parallel to the axis, so it can either reach inside a drilled hole in the workpiece to enlarge it, or can move along the face of the end of the workpiece.

There are versions which have a third station, and perhaps even a forth one. For up to three stations -- it is still intended to have only one toolholder at a time. Among other things, the locking system is not assured to lock fully on more than one station at a time.

The post which you have is capable of having two holders installed and tightened equally, as there are separate screws to lock up each station -- just as there is for the Dickinson style toolposts used on Myfords, and on my Compact-5/CNC. Actually, the one for the Compact-5/CNC would probably be very good for the Taig as well. It is way too small for my 12" Clausing. :-)

Aloris does have a four station one with individual locking for each station, so you can set it up like a turret toolpost with your choice of tools -- though usually you have to leave one station empty, as a turning tool with a boring/facing tool one station clockwise from it will have the tools interfering with each other. But the four-station toolposts are designed to be rotated from tool to tool after being loaded with the needed tools in the various stations. This is like the four sided turret toolposts found on some machines. Ideally, these have an indexing mechanism so you can rotate the turret precisely one face at a time without having to take time to set it up precisely at each change.

Perhaps -- though try to also retain its function as a setscrew (just use a longer one) so you grip the tool in the middle as well as at the ends to minimize bowing in the middle which could lead to chatter when cutting.

Not sure about the ones which fit the Taig size of lathe, but the ones for the AXA and BXA sizes hold a pre-made blade parting tool, and hold it at an angle so you don't have to grind a rake angle into the top of the tool. I tend to use "T-profile" parting tools in mine. The profile looks sort of like this (view with a fixed pitch font like Courier, as proportional pitch fonts are likely to produce distortion). /~~/ / / / / / / /__/ / ~ [ ]/ ~ || ~ || ~ || / About 15/16" high -- for the BXA size, smaller for the || / AXA. About 6" long. || / ||/ The '~' mark where the drawing is cut off. --

The above is the end-on view, and the wider top and narrower bottom makes it easier to set up the tool so the bottom does not drag on the sides of the cut.

The top of the tool fits against the top of the slot in the holder, and near the front of the slot is a cutaway where a tapered piece fits in and is drawn by a long screw to wedge the blade in place. If you adjust the degree of extension (either by sharpening the tool bit by grinding off some of the end, or by loosening the clamp and sliding the tool out to cut closer to the center of a large workpiece, or pulling it in to make it more rigid for cutting a harder material) you will need to re-adjust the height. If you have an extension which you use most of the time, you might want to make a gauge which could allow you to restore the normal extension quickly after sharpening, so you don't have to adjust the tool height.

O.K. As long as you realize that it is an awkward tool to use in metals with such a small lathe. It might be nice for getting a nice finish on plastics.

Enjoy, DoN.

This would only be possible by cutting a 7/64 hex key very short and tightening the screws 1/8 turn at a time and then only for tools directly opposite each other - you cannot fit two holders on at right angles. I venture it is quicker to use only one tool at a time as one can access the screw head through the hole opposite. Doing it the other way would probably drive me crazy very quickly.

OK, I did not realize that could be a problem. The Taig toolpost that came with the machine has only two set screws. I note that the LMS toolholders have four.

Perhaps this sort of arrangement might work:

I found it:

The one I have has a V-profile with the top of the V whole 0.002 wider than the bottom and the whole V is tilted about 7-10 degrees off vertical.

As a matter of fact I wondered about the rake angles for parting tools. They also sell (as do others) parting tools ground from a 1/4" bit. I could find no info about their geometry.

I shall have to look at one to appreciate it. But it answers one of my questions (I think): The parting tools also need a rake (at least for aluminium and steel).

I think the guy had to have worked with plastics a lot. Some of the other tools have big contact areas. There are other what I take to be parting tools with the top of the V 1/8" or more and no rake. I tried them on aluminium just to see what happens and stopped pretty sharpish.

This is turning into a full time job :-) Today I bought $15 digital calipers and after an hour of experimenting I think I found a way to convert them to measure the carriage travel. Some flower baskets are next...

[ ... ]

You can if they are short enough -- or have 45 degree beveled ends.

There is no reasonable need for two on opposite sides of the post.

Indeed so.

The more setscrews you have, the more rigid the clamping for a longer tool. If you only can use two, use one near the cutting end and the next one in, so the spacing is minimized.

Hmm ... if you've got a place to mount it. As shown, it would remove the middle screw from play as a clamping screw.

O.K. Those are piston style, which certainly could not handle two tool holders at once. The lever turns a cam inside the body, and the clamping position for the lever is 90 degrees different for the two stations. (The wedge style moves two wedges down at the same rate, so two holders of *precisely* the same size in the dovetail would clamp at the same point of lever travel -- but the odds of such precision in dovetail width are pretty slim. :-)

The holder for the parting tools has no rake -- this one simply clamps through the bar along the top being held down by the four cap screws. This means that you will have to grind a little rake at the end of the parting tool's top. And after a certain number of re-sharpenings, you will have to grind off the end and make a new rake.

All of these parting blades seem to be of the 'T' shape which I described.

That is the kind which was made for the old Armstrong style tool holders to go into lantern style toolposts. Those used the angles at the top and the bottom to clamp the parting tool into the holder, but you would have to grind the top flat from side to side, and with a rake for proper parting.

A trick to make the 'T' style work even better is to grind a shallow 'V' parallel to the length along the top. This causes the chip formed to be pinched in narrower, and thus to clear out of a deep parting slot more readily.

The tool itself probably has no rake, but some toolholders can provide an adjustable rake. One style, which I originally found on jeweler's style lathes, has a segment of a circle at the bottom of the slot, and a rocking steel wedge which fits the curve. You adjust the angle (and the height of the tip) by loosening one clamp screw and tightening the other, to change the tilt of the rocking steel wedge. Of course, the bottom of a lantern style toolpost has a similar rocking piece, but only one clamping screw.

Yes. You *can* make a rake by grinding the top, but your tool lasts through more resharpenings if you have the rake built into the holder.

In the case of the holders which you pointed out, this would require the parting tool holder to be taller. Perhaps aim for about 8 to ten degrees rake.

I like the choice of thicknesses offered in the actual parting tools.

[ ... ]

:-)

Of course. :-)

The main thing is to preserve the part covered with the fabric in the beam. The jaws can be milled off without problems (ideally with the head removed at the time. :-)

:-)

Enjoy, DoN.

P.S. That 3" milling vise looks cute. A clone of the Kurt Anglock style, but smaller and more affordable. Now if I could just find a 2" of the same design for the Emco C5 mill (adaptation of the mill column for the Compact-5 lathe, but with a heftier X-Y table below it.

These *aren't* :-)

Seppuku?

After your comment it would make more sense to make this arrangement on the distal set-screw rather than the middle one.

It seems less hassle than having to grind a whole new parting tool from 1/4" stock.

I have seen a home made one like that.

It just occured to me that it might be simplest just to make a separate toolpost just for the parting tool along the line of the original Taig toolpost just with a shallower groove inclined at 8-10 degrees and half an inch wide to allow the use of commercial parting blades *if* one parted at a single distance only. Is the groove on the toolholder that holds the T-shaped parting tool shaped in any special way or can one just get away with a rectangular profile?

Which is why I am interested in the commercial ones rather than having to cobble something that small and thin using a bench grinder.

I took them apart and put back together again. The main hassle I see is to find attachment points on the Taig. I hate drilling and tapping any of the tools if I do not have to. Fortunately the Taig has a surfeit of T-slots.

??? Which one? LMS?

That's what your milling machine is for. :-)

>

What about if you use the middle screw, and make it a particularly long one, with the knurled height-adjusting nut and the locknut below the head but well above the holder? You'll have to loosen the locknut and re-adjust the height nut anyway if you change the tool bit in the holder, so that should not be a problem.

And you don't need the extreme overhang anyway -- just a knurled nut large enough in diameter so it overlaps the side of the toolpost. The overhang on that one would proably reach to the middle of your holder, which is just air anyway. :-)

I can't seem to find the 1147 toolpost that the one with the overhang fits anyway. :-) I wanted to see just what that screw was supposed to touch.

[ ... ]

>

Agreed.

[ ... ]

The groove is a little deeper where the wider T-head is. Or the slot is slightly tilted to fit the V-shaped parting tools, and this works with the T-head ones as well.

But why make a separate toolpost -- just make a separate tool holder to fit your existing toolpost.

Understood.

Indeed so.

This one:

It showed up in the left sidebar yesterday. I had to search for it today. They seem to move these things around.

Enjoy, DoN.

[...]

After milling 8 t-nuts down to size over a whole afternoon I am wary of doing the same to 15 or so very small parts when I can use one at a time :-)

[...]

I could not find it either. I am sure there are several ways to skin this particular feline.

OK. I suspect that the depth and width of the part of the slot that accommodates the transverse portion of the 'T' is not critical - as long as the vertical part of the T is snug against the side of the holder. This should be doable even with my Kalashnikov-like skills.

I have two toolposts now:

1) the original Taig which clamps the tools into it directly - there are no separate holders 2) The "auction" toolpost with many holders, none of which would take a 1/2" parting tool from LMS. Each holder is 0.612 tall. Any taller and the height adjustment will diminish significantly. OTOH It may be worth having a go and make a slightly taller one but given the way the holders are milled to fit the post it will not be a simple propostion - not in my hands, anyway.

The thought was simply to take an existing chunk of aluminium and mill a 10 degree inclined slot with a deeper portion near the top, drill and tap for set screws and a central holding screw, make a posh handle like I made for the Taig toolpost and voila! However, if my daughter's guilt stretches to a LMS QCTP I shall be grinding tops of the parting tool to get the rake. No point having a dog and barking yourself.

BTW, in my studies I came across an interesting conversation from this forum that you had about year 2000 with a gentleman called R. Bastow (sp?) who I believe went under the pseudonym "tee-nut". It related to parting tools and their use. He seemed to advocate a side relief ground in the top part of the tee back from the cutting edge as well as the shallow v-groove along the top like you mentioned earlier. Actually it was only then I grasped how it was supposed to work but could not get to visualize the practicalities of making such a feature. The nearest I got was clamping it in the mill vise and run a pointy contersink along the top.

Interestingly, he never mentioned the top rake but at his stage of life he may have been taking it as given. I read a few of his other posts and his knowledge of the subject seemed encyclopaedic.

Talking about spirited threads, I have to mention another one that I came across: Ed Huntress holding forth on grinding HSS tool bits in 2001. A really well presented argument including extensive research showing convincingly (to me anyway) how an oft repeated lie becomes the truth.

[...]

Just like most supermarkets. I have got a 2" which looks similar but then I would not know the subtle differences. All's I know that mine still lifts things up a bit when tightened.

Mill a long piece of stock to the T-nut profile, and then cut it into individual T-nuts. Probably a good idea to drill and tap them all before cutting them free.

[ ... ]

Indeed.

[ ... ]

No problem with the right sized cutters.

Right. I've actually got two of those -- one for use without the headstock riser block, and one for use with it.

Two V grooves the same depth and the proper spacing apart. Easiest with a horizontal mill with two V cutters separated by the right size spacer, but doable by other systems as well.

The screws really should operate a clamp bar, as it is easy for setscrews to slip on the narrow top of the parting tool.

:-)

Yes -- it was a serious loss to the newsgroup when he died.

That sounds like a good way to dull the countersink. The parting tool is HSS (High Speed Steel) and likely even a high cobalt version thereof. What you want is a grinding stone in a Dremel type tool, with a diamond used to dress the stone to form the negative of the 'V' needed. Something like this: ________ [] || ||

With the industrial tool holders which he was familiar with, the rake would be provided by the holder. It is only when you get to the tiny ones for Taig and Sherline sized lathes that you lack this.

Indeed so.

The thread about whether you should quench the HSS as you grind? I agree with his position that you should not.

Event the Kurts need a little help. They now come with some small O-rings which fit under the moving jaw, and are compressed by the pull-down feature to pull down the workpiece at the same time. The design of these is that there is an angled projection below the moving vise jaw which engages a matching angle on the moving nut, so when you tighten it it slides on that angle to pull the jaw down tightly. Some of the clones have a problem in that the angled portions are not ground smooth, so they stick instead of slide where they should.

Enjoy, DoN.

These were nuts in a clamping kit that did not fit my slots. One by one. All six surfaces. Good for the character...

Several sources including Taig dealers allude to a "rear toolpost" - apparetly you can clamp the parting tool upside down and mount it in the rear post the other side of the spindle. I could not work out what the benefit of such arrangement would be.

Ah. What about an arrangement like this one:

A dental drill in the mill??? Comrade Kalashnikov does not get on with Dremel...

I have no reason to disagree. I thought the argument was compelling. I watched a DVD recently published by a prolific author and machinist who dips his tools (in a nicest possible way) when grinding. Throughout the program I wondered why you would worry about a bit of heat in HSS which will get hot working anyway and was developed for that reason.

I think the issue is almost a social commentary on human behaviour. Was it Stephen Covey who said "If you want to find North it is better to consult a compass than to take poll of all those present"? You would have thought that such issues would not arise in something like engineering which is a discipline on the whole based on facts (unlike medicine or politics). Yet it happens. I still remember the discussion on crimping vs. soldering and the passions involved in that one!

I still think that it would be easier to make one long one and cut it to make multiple ones -- rather than trying to fix a bunch of purchased ones -- especially if the purchased ones are partially hardened as they should be.

The chips fall down from the slot instead of building up on top of the parting tool.

The stresses on the carriage are different, and if the carriage moves, it clears the slot a little, instead of possibly digging in and breaking the parting tool.

I would use them on my Clausing, if the cross-slide were equipped with a rear T-slot.

Hmm ... first off -- I don't like that topmost photo, which is encouraging you to grind on the sides of a standard grinding wheel. There are wheels made for such use -- but the standard ones can break as a result of the lateral loading, spewing chunks of stone at high speed towards everyone nearby.

As for the side clamping -- you would have to mill a groove in the holder, and a matching groove in the clamp plate, to clear the wider 'T' top of the parting tool. You can make the groove a little wider than needed to allow for slight mis-positioning of the grooves, as long as you have a lot of meat clamping from both sides.

As for using the hacksaw blade -- fine for shallow grooves for C-clips and the like, but bad news for deep parting, as the blade will almost certainly bend and give you either a concave or convex end which will need to be trued with a facing tool.

The mill doesn't spin fast enough for what you need -- and a dental drill will burn up like a countersink would. The cobalt HSS of the parting tool is too hard to use metal tools on -- you have to

*grind* it.

But -- the precision is not that critical -- use a hand-held Dremel and guide your hands by the vise which is holding the parting tool with just the 'T' head clear.

He would have the habit of quenching because he *started* machining back when high carbon steel was the common tool bit material

-- and quenching was *necessary* for those, or the tool would get hot enough to anneal.

HSS changed things a lot -- but not for everyone. And the habits of quenching lasted a long time as people learned from other older machinists.

:-)

Machining is an art as much as an engineering matter.

:-) (Of course, it helps that I have a large number of crimping tools and the terminals to use with them. I learned about crimping working for an aerospace manufacturer, and while I also learned how to do *good* solder joints where required, I prefer crimping if I have a choice.

Enjoy, DoN.

=A0 =A0 =A0 =A0 =A0 =A0 =A0You would have thought that

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Yet it

I think some of the dispute comes from listening to the old guy who is supposed to know everything. I am becoming that old guy and have made an effort to read the appropriate manuals instead of repeating whatever I heard way back when. For example:

IIRC the specs for one of their terminals give current ratings from

50A for a hand crimp to 350 for the high-end hydraulic press dies.

jsw

When I grind tool bits, I will probably cool the HSS periodically. Not because the HSS needs it, but because if I do not cool it, it burns my hands. This may theoretically lead to microcracks. But since I usually do some light grinding on the fine wheel after all the heavy grinding, I figure the layer with any microcracks is ground off. Sometimes I even polish the HSS using some fine sandpaper. At any rate I have never observed any problems from keeping the HSS cool enough to hold.

But do not accept or reject what I say without having tried it. Theory is nice, but sometimes it just does not make a difference. That is what I have found about polishing HSS tool bits. I read it is suppose to provide longer tool life. But I am not convinced. Certainly there is no dramatic difference in tool life that is obvious.

Dan

Possibly. At an additional cost.

OK. Worth considering then.

So fiddling with a 1/4" piece does not seem so bad after reading this. There is of course always the commercial option :-)