Diamond tool holder.

[Les Jones 1Participant @lesjones1]

Hi Chris,

                  This is a reply to your post at 18:43 yesterday. I went down to my workshop this morning to have another look at the tool holder. I milled the top of the clamp screw flush with the side face of the holder. (Rather than facing it in the lathe.) This gave me the required clearance and left enough metal left on the screw head. I have put a few pictures of it on an experimental web site I am building.

Les experimental website 

 I did try ticking the remember me button a few days ago and it seemed to solve the logging out problem but I forgot to do so yesterday.

Les.

[Paul BoscottParticipant @paulboscott25817]

All

Just got a Diamond tool / holder from Eccentric Engineering UK it works very well

 

Paul

[chris stephensParticipant @chrisstephens63393]

Hi Paul,

Another convert?

Welcome to the club (of enlightened turners). 

chriStephens 

[Mark BusParticipant @markbus97330]

Hello everyone,

                          I finished making one of the MEW 156 toolholders two weeks ago and I just want to add my praise . I tried it out on different types of steel , brass, and bronze and it worked well on everything. I liked it so much I made a second one to hold  .250″ toolbits. This one has a about a  .500″ shank with the bit holding screw lowered slighty.On this holder I used a truss headed machine screw to hold the bit; no nut. It seems to hold the toolbit securely. Apparently a truss head machine screw has a larger head than a regular machine screw.

                           I know the toolholder won’t work in all situations but I appreciate the ease of grinding the toolbits. I’ve never been able to get the hang of grinding toolbits freehand and I’ve never gotten around to building a proper grinding rest with fences.

                           I too would like to see that description of the threading toolholder. And does anyone have any ideas about making a round bit toolholder?

                           For what it’s worth I have a Chinese mini-lathe.

Mark

[_Paul_Participant @_paul_]

Mark,

I’m keen to make one of these also do you have any pictures of yours you could post please

 

Regards

 

Paul

[chris stephensParticipant @chrisstephens63393]

Hi Mark,

If that was my threading toolholder you were referring to, it was on show at Sandown last year, but no one took much notice of it. The trouble with putting things on show, especially toolholders, is that they are so very much unspectacular when just sitting on a stand. The only way that any one can see the benefit of a particular tool is by watching it wok, or better still using it.

have not written up the way of making it, yet, but due to various restrictive practices the only place that I would be tempted to do a write up is in the SMEE journal. Thinking of which, there is a picture in the latest issue (photo 7 page41) of my Mk 4 tangential toolholder, this one looks a bit like an Eccentric but is of one piece construction. If you are not a member of SMEE shame on you but I am sure you must know someone who is and have a look at their copy.

chriStephensI

[Ray LyonsParticipant @raylyons29267]

Hi Everyone,

I saw the item in No 156 and when visiting the Midlands Exhibition last October,bought a suitable piece of metal and put it in the stock rack when I got home. Forgot all about it until last week, when looking for something else, this piece of bar popped out.

I immediately pulled the item in 156 and copied it for use in the shed. I did make some changes, increasing the length to ensure all clamping screws on the toolholder are gripping, Cutting a V instead of a channel to hold the tool and threading the bolt direct into the tool rather than using a bolt. I also made a square washer to act as a clamp on the toolbit.

My 1/8″ toolbit which I pulled from stock is something other than HSS, much too hard for the purpose, something special. Could be something I bought some time ago but forgotten now, so I had to use the next nearest, a piece of 3/16″ HSS,

When I tried the tool in the QC tool holder on my Myford S7, it would not fit, too high by about 1/4″. The only way I could use it would be to remove the toolholde and go back to the old clamping method so I tried it on my Warco BG600. It fitted perfectly and I was impressed with the trial cut on a piece of 11/2″ MS. I then tried a deeper cut only to find that chatter set in when the toolbit was pressed back into the tool. On examination, it was obvious that the 3/16″ was relying on the grove for location only so tonight, I cut a deeper V and again tried it on the Warco. I made two cuts, one about 1/16″  followed by another much deeper. Very impressed, this time it was an old piece of heavy gauge galvanised pipe, not the best of steel but the cut was clean and without cutting fluid, the swarf was very hot and discoloured.

I now intend to make another tool for the S7 but with the head set down by about 1/4″ and a slightly greater width of body to take the extra depth needed for a 1/4″ toolbit.

 

Putting this on the must buy list for the Bristol Exhibition next month. 

[John ShepherdParticipant @johnshepherd38883]

There is probably enough endorsement already to justify owning one of these tools but I have just finished making one to the basic design by Peter Boonham in MEW but using a 3/16 toolbit and I am very impressed with the results so far.

 

Most importantly I have just been able to easily machine a small eccentric for a  1″ Minnie lubricator that has previously proved impossible  for me using inserted carbide tooling.

 

For the same reason that you would not have just one spanner in your toolbox, I will not be making my other tooling (that includes HSS, brazed and inserted carbide) redundant but I can see that the tangential will spend a lot of its time in the toolpost.

 

On the basis that good value is not necessarily cheap, had I bought the commercial version I am sure I would have regarded it as good value for money if it performs as well as the home made one.

 

Thanks to Peter for the article and the inspiration to make it.

[Mark BusParticipant @markbus97330]

Hi Paul ,

              I’m working on trying to post some pictures. i don’t have a computer so it’s difficult ; I have to rely on the kindness of friends.If all else fails I can talk you thru how I made the toolholder.

               Mark

            

[John HaineParticipant @johnhaine32865]

Well I spent quite a while making my own version last winter, but only yesterday got around to grinding a tool up for it.  After machining a bit more off to obtain enough clearance I found it works a treat, though I think I need to have a slightly greater clearance on the tool. 

 

So, a question to those who have used these a lot: though it cuts very easily, the finish isn’t wonderful, I think because of the very sharp tip.  How much rounding do you give the tip, and how do you do it?  I rubbed the appropriate edge of the 3/16 toolbit on a diamond lap and just took the sharp corner off.  Is there any other secret to getting a good finish?

 

All suggestions gratefully received!

[Michael Cox 1Participant @michaelcox1]

Although the tangential toolholder described in MEW 156 is not difficult to make I have designed a similar tool which avoids having to set up compound angles for milling. The holder is easily made from a piece of 1/4″ steel plate. Full details are on my website:

http://mikesworkshop.weebly.com/tangential-tool-holder.html

Mike

[chris stephensParticipant @chrisstephens63393]

Hi John,

It’s been a few years since Ascot!

Now about your problem, I usually just round the corner with a few strokes on a diamond lap down the whole length of the HSS bit, don’t just do the top or you will loose clearance. The angles you need to work to are 12 deg forward and to the side and grind the tool’s top to 30deg. If you use a clamp screw and it touches, can you lower the holder and have more tool projection to give better clearance?

 

When you say you don’t get a good finish, is that with a roughing or a finishing cut. The finish cut (2-3 thou) will be be better, unsurprisingly. One way to improve your finish is to make a cut and then, while the work is still turning, slowly run the tool backwards if the tool is sharp you will get “angels hair” and a pretty damn good finish. If you want a tool for “super” finish, raise the tip slightly above centre and cut backwards, this gives you a shearing cut with a tool of “infinite radius” and a near perfect finish, depending on material of course.

 

Another thought occurs, how are you sharpening your tool?  Do you merely grind or do you hone after? Personally I find honing counter-productive, I grind with an 8″ 80 grit wheel and leave it at that. This gives a fairly flat curve to the top which is a bit stronger than say a worn 6″ one would do. Which type of holder do you use for sharpening, I find the 30 deg Vee type to be superior to the commercial design, but that is just my jaundiced view. The commercial design is great for sharpening threading bits, so should not be dismissed.

 

If you have a specific question you can PM me, or if the others might benefit ask in this open forum.

Are you going to Ally-Pally?

chriStephens 

[Keith Wardill 1Participant @keithwardill1]

The following link has some useful info on tangential tools and toolholders – may be of interest (whole site is pretty good IMO)

 

http://gadgetbuilder.com/ToolHolders.html#Tangent

KeithW

[John HaineParticipant @johnhaine32865]

Thanks for the suggestions Chris.  I took the same approach to rounding, but maybe it needs a few more strokes.  My holder has the clamp screw from the opposite side with a clamping piece in the tool slot (which is twice as wide as in the simple design – seemed a good idea at the time but was fiddly to make).  Clearance problem was at the front, but easily sorted.  I was using a finish cut of 0.1mm (4 thou) under CNC, but using a turning wizard which only cut towards the h/stock … I need to play around a bit with speeds and feeds I think, and maybe rewrite the wizard to allow a finish cut in the opposite direction.  Good idea to try finishing with the tool a bit high, I’ll give it a whirl.

 

I ground the tool on the Quorn with a cup wheel, this gives a flat face, and if I finish off with passing the tool across the wheel until it sparks out it has virtually a mirror finish.

 

However, first impressions are that this is a great tool.

 

Yes, I should be at Ally Pally, are you demonstrating again?

 

John.

[George ScollayParticipant @georgescollay44108]

Hi Chris,

                     You will not be disapointed with the tool,I purchased one about a year ago and never looked back I know it is a bit expensive but everything is there and it is so easy to sharpen again even for a beginner as I was at the time (and still learning)

[chris stephensParticipant @chrisstephens63393]

Sorry if this sounds like a PM on an open thread;

Hi John,

Yup, will be on the SMEE stand again, we will be allowing anyone who wants a go to have a try on our new SuperC3, which was generously donated by ARC. One of the tools will, most likely, be a Tangential tool so you can have a look provided the youngsters don’t get in the way.

I tried sharpening my bits on a Quorn, but had more success, no change that, it seemed to be better on an ordinary grinder. I wonder if the very fine striations left be a grinder act like little saw teeth and help the cut, rather like scissors only work properly with a little  roughness. 

chriStephens 

PS I have you, John, a PM 

Edited By chris stephens on 02/01/2011 19:22:41

[John HaineParticipant @johnhaine32865]

After further experience and thought…

 

I discovered that I was cutting too fast – hangover from tipped tools! Slowing the lathe down solved the finish problem, can now get near-mirror finish, excellent. This is without feeding the tool “backwards” on the finish cut or raising it slightly.

 

Small problem with cutting edge getting deformed – Chris at Ally Pally suggested that this was due to unsufficient tip rounding, so need to hone a bit more off the HSS steel square blank to improve that.

 

I was also wondering what the actual cutting angles were and how to set up the angles on a conventional grinder that holds the tool bit “flat” rather than “diagonally” on its edge against a cup wheel (think of a Worden), so did a bit of geometry. You need to know by how much the tool should be angled in the horizontal and vertical planes to give the equivalent “diamond” angle. There is a simple formula as it turns out. If the “diagonal” angle is d, (d=30 degrees in the usual tool), the H and V angles should be arctan[tan(d)/1.4142] .

 

For 30 degree diagonal angle H and V work out to 22.2 degrees. With 12 degrees cant forwards and sideways on the tool the side and front rake then work out at 10.2 degrees…..seems to me this might be a bit much for some materials, but the formula lets you work out alternatives. For brass for example you would want H and V to be 12 degrees to give a flat-topped tool when held in the tool holder (i.e. zero rake). The end face of the bit will then be angled at 16.7 degrees along the diagonal. Or, for 8 degrees top and side rake, H and V need to be 20 degrees, giving a “diamond” angle of 27 degrees.

 

I hope someone else finds this information useful.

Edited By John Haine on 30/01/2011 11:01:02

[mgjParticipant @mgj]

John, like Chris, I have done much better with the curved surface, rather than a flat Quorned one. (Except on brass – predictably brass and bronze don’tt like the high rake, and grab – AKA as not feeding fast enough)

 

Like Chris too I have rounded the cutting point a lot, and one can get a very good finish at some speed, and on .200 cuts..

 

One mod. – I have taken 13 degrees off the front face, so my bit looks a bit like a reversed screwcutting job. That means I don’t have to offset the tool post, because I have a degree of clearance, and thats a big advantage. Unfortunately the diameter of bar one can face is not great,but its a lot better than constantly pratting about with the toolpost every toolchange – unless you have a Stevens type of holder. I have one, but 2 lathes, so the second tool is one of the Oz ones.

[jomacParticipant @jomac]

Hi i read all the posts on the tangental tool holder, and because Im’e like a lot of you, I cannot afford to spend much money on tooling, So I make my own. First I cut a piece of 16mm cold rolled square 110mm long, Cut a piece of 10mmX50mm flat steel. Put the flat, length wise in the tilting vice, at 45degrees used an 8mm end mill and cut a groove a little less than half the diagonal measurement, the center of the cut about 6mm from the edge Then cut the oblong into two sections. One of these I ground a 15 degree angle at the rear end of this, so that it was pointing to the left, ie, towards the chuck when it was mounted in the tool holder, then ground a 12 degree angle onto the front edge of the 16mm square, then clamped the flat section so that the groove was at the front and the top of this was flush with top of the 16mm, I also ground a deep chamfer on the edges I was going to weld together. I know this sounds difficult, its not, what is, is doing it by your self without proper clamps, or a second pair of hands, anyway you only need a small tack weld to start with, that way you can bend it into the right position. fully weld it togther when you are happy with the position. Clean up the welds The reason I offset the tool only 15degrees, was that it gave me more clearance. Next I put a spotweld at the rear of the second piece of steel,(to act as a pivot point) I put a 1/4 inch HSS in postion and drilled as close to the HSS to tap for a 6mm round head bolt, and clear drilled the welded one, plus recessed to half cover the head, Bolted it together and with the HSS below the marks, cut and ground off the exess, without weakening the welds.

I made a sharpening jig out of timber and, the same as in the model engineer article, it works OK, I also made one out of 12mm steel, milling a slot upwards 12 degrees and angled about 22 degrees, That work too, The timber jig is good for grinding 1/4 round HSS,

Now the big question is does it work, YES. gives a good finish with both bits, BUT if I made another one, I would use two locking bolts, as when taking very heavy cuts the tool bit gets pushed down and below the the work piece,( I had to use a lot of strength to get it to lock up properly).

I tried various angles of attack for the tool bit, to arrive at a reasonable result. You might do better. because I also added a 3 degree angle, to give clearance, It might not need it ?????.

Good luck.

John Holloway.

[Norman WillcoxParticipant @normanwillcox10519]

Has anyone got some sketches of successful home-made Tangential cutting tool holders please?

I have just made a simple prototype but there is insufficient clearance to the centre. I can’t mount directly on the cross slide on my Harrison 9″

Norman

[NJHParticipant @njh]

Hi Norman

 

MEW 156 page 12.

 

Regards

 

Norman (!!)

[jomacParticipant @jomac]

Norman Hi, Can you under stand what I did with my tangental tool holder, In the description above, So far it cuts very well with both, the square and round 1/4″ HSS. Mine has an offset to the left but if you do one that is straight, you only need to mill, or just do cuts with a hacksaw and file, and not do fiddle welding. Can’t send drawings or photo’s yet!!!. cause I need my grandson (who is down south in Victoria), to help, trouble is he just started Uni doing Vetinary science. and cannot come up here to help.

By the way. I modified mine, to use two and not one, cap head locking bolt. With one bolt there was a tendency for the tool bit to drop down below the center line, when taking heavy cuts of 3mm or more. Now it does not move at all. Also on the square bit, Hone a small radius at the front, it will give an even better finish.

PS. I was turning something using the round tool bit, and did not move the saddle back far enough, turned the chuck round by hand, ouch!!! drove the razor sharp bit, 1/4″ into the back of my thumb.

John Holloway.

[Les Jones 1Participant @lesjones1]

Hi Norman,

I don’t have any drawings but I have some pictures on my website of the one I made based on the article in issue 156 of MEW that HJH mentions.

This is the page on my website.

Les’s website.

 

I hope that helps.

Les.

Edited By Les Jones 1 on 25/04/2011 12:39:42

[Norman WillcoxParticipant @normanwillcox10519]

Hi NJH, Jomac and Les Jones1,

Thank you for your replies.

Search as I might yesterday I could not find the download of MEW 156 page 12. Sorry if I am being a dim forum user.

I have found Jomac’s description and I will absorb it but I have only a MIG welder, which seems to be failing in power, and I have been forbidden to use it because of my pacemaker – advice I have ignored several times, safely so far. I am sure that I could not achieve the required joint though.

I viewed the pictures by Les Jones and this is a bit similar to the one I have made. I found someone else’s pictures yesterday, showing the double angle set-up on the milling machine to make the slot at 12 degrees in two directions. I cannot find them today!!! I tried to copy this design, though I put the bolts in from the tail-stock side. This fellow bolted his holder directly to the cross-slide but I can’t do that.

I think I may be able to make my prototype work by cutting off the head and bolting it on the underside of a steel section to be held in the toolpost, thus dropping it.

I would like to see the MEW version.

Why can’t I find these recent posts on this thread?

Norman

 

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