Tangential tool holder?

[Andrew Jones 7Participant @andrewjones7]

Hi all, first post so sorry if I'm repeating others. Having just started back into the hobby I have read with interest about tangential tool holders, I would like to ask if any are commercially available other than from eccentric engineering? I'm looking for holders that would accept 1/4" toolbits as I have a good few of these and it looks an ideal holder to use them with. Thanks Andy.

[Andrew Jones 7Participant @andrewjones7]

[chris stephensParticipant @chrisstephens63393]

Hi Andrew,

You can make simple, but more than adequately efficient, ones from plans on the net. Try "Gadgetbuilder" or "Ralph Paterson plans" not forgetting Michael Cox for more info. Or back engineer the ones in my photos.

It is certainly worth making one, it is even worth buying an Eccentric one, as they do live up to the hype.

chriStephens

PS I almost forgot, there is a Swiss company that makes one but if you thought Eccentric pricey better not to look at "Ifanger", oh and they use their own special bits not standard square stock HSS.

[Paul LousickParticipant @paullousick59116]

My tangential toolholder from Eccentric Eng is one of my better tooling investments. Cuts well and a breeze to re-sharpen.

If you take too deep a cut and the tool digs into the work, the toolbit is pushed down into the holder and does not break. Just re-align the toolbit in the holder and start cutting againt. Great for us learners.

They now have a new super tough material which is supposed to be better thaf HSS. Have not tried it yet but intend to get some.

[John CoatesParticipant @johncoates48577]

There were examples of how to make one in MEWs 157 and 179

I followed one of these and am very happy with its performance

John

[SpringbokParticipant @springbok]

Hi Andrew
there has been a lot written about them all good would be worth your while doing a search on this forum and other ME forums
Bob

[Andrew Jones 7Participant @andrewjones7]

Thanks for the replies, I had searched and after reading all the comments I decided to go with one, sadly I haven't yet got a mill sorted so was looking to purchase one and was surprised by the lack of commercially available ones. It does seem to be a very useful tool and I do like the ease of sharpening.

Andy.

[chris stephensParticipant @chrisstephens63393]

Hi Andy,

No matter how good they are and no matter how convenient they are, they are not good or convenient enough for industry to use. Although having said that, there are probably more lathes in home use these days than there are in modern British industry (?) but then again, we hobbyists are cheapskates by nature and prefer to make our own.

chriStephens

[Nigel BennettParticipant @nigelbennett69913]

I think it's true what Chris Stephens says – at our company we just don't use HSS. If it isn't carbide purchased at huge expense, our turning secton chaps don't want to know. I think it's a somewhat blinkered view – I still think HSS has a role to play in modern machining, particularly for low-volume stuff when the set-up times are more than the machining times..

[jason udallParticipant @jasonudall57142]

Posted by chris stephens on 24/04/2013 12:23:35:

Hi Andy,

No matter how good they are and no matter how convenient they are, they are not good or convenient enough for industry to use. Although having said that, there are probably more lathes in home use these days than there are in modern British industry (?) but then again, we hobbyists are cheapskates by nature and prefer to make our own.

chriStephens

They have in the past been used widely.. but hss and carbide have largely super ceeded them ..on CNC even HSS ( even in a tangential holder) doesn't last long enough at the feeds and speeds today..

When I started "hobby" machining I had not seen these in use and I looked at the problem from 1st principles and came up with a way of reducing tool "grinding" to one face ..thought myself so clever…spoke to an old boy about it …" oh yeah.. got one like that around somewhere……here you go" now this tool holder take 1" HSS ..and is far too big for my needs but I was suitablly crest fallen…..

Any one tried round section hss for one?…much easier to drill holes round…

Enjoy

[Ian S CParticipant @iansc]

Tools of this type have been in use for over one hundred years, and is mentioned in year one (1898) of Model Engineer. Ian S C

[John McNamaraParticipant @johnmcnamara74883]

Hi Andrew Jones
Hi All

Due to the HSS bit in a tangential holder being angled and at the same time being diagonal you can cut a true 90 degree step in a shaft (Having set the axis of the tool at 45 degrees to the work), without resetting the tool. or 55 or 60 degree threads by grinding only the end face of the HSS. I like this feature, My other conventional holders require grinding the HSS on several faces, OK not that hard after you have learnt to do it but a waste of material. inevitably you end up having to grind of a few mm off the HSS to get to a fresh end so you can grind in the relief angles. often 5 or so mm. more for thicker HSS tooling. Tangential tooling only requires you to grind of a few thou, to get to a sharp tool again. (I normally grind in a tiny 1mm radius on the tip after grinding the end for a better turned surface finish. Maybe easier to do with an oilstone if you don't have a fine grinding wheel and a very deft touch)

BTW not all HSS is created equal. It is false economy not to buy high quality Cobalt HSS tool bits from a top supplier like Sandvic or the like. Talk to an industrial tool supplier

Although I have not tried it It would be interesting to try a carbide blank in place of HSS in a tangential holder. For free I guess you could braze a small tip on the end of a piece of mild steel then grind it up and try it in the holder. A lot of carbide tooling is set with a negative top rake to strengthen the cutting edge. particularly cutting steel So the top rake might need to be reduced. Hopefully not much or you would not be able to cut a 90 degree shoulder. It would be a good use for the jar full of blunt tips that never seem to come in handy, I have collected over the years.

Another one to add to my to do list!

Cheers

John

Edited By John McNamara on 24/04/2013 14:24:28

[chris stephensParticipant @chrisstephens63393]

Hi Jason,

Yes and one is used on the SMEE lathe when we allow beginners to have a go at making something, it is used to make the groove in the pulley.

Hi Ian,

Indeed they are not new and I have made a copy of the "Haydon tool bar" from 18something or other, but I will stick with a more modern design.

Hi John,

Been there, done that but the T shirt shop was closed. The problem with a solid carbide tool bit is that,to prevent the corner chipping, you need quite a pronounced radius (at least a couple of mm) on the corner. This is fine for most uses but stops you getting in a sharp corner.

chriStephens

[Andrew Jones 7Participant @andrewjones7]

Well I've spent some time thinking about it and I am going to have a go at making my own, I can manage with the tools I have, what are peoples thoughts on the best material to use for the holder? Should I be looking at something like en19 or is something softer suitable?

[steamdaveParticipant @steamdave]

Andrew

Whatever steel you can lay your hands on will be plenty good enough. Some have even made their holders for QCTPs out of aluminium.

Dave
The Emerald Isle

[John McNamaraParticipant @johnmcnamara74883]

Bear in mind clamping the HSS tool bit is an issue. The cutting force tries to push the tool down, And unlike a conventional holder where the force is against the side of the holder with a tangential holder it is pushing it through the holder this requires strong clamping.

I suspect it would be difficult to clamp aluminium sufficiently tight. Unlike steel aluminium has a tendency to creep under bolt heads, this will lessen the clamping force. Also Aluminium is subject to much greater bending deflection

I suspect steel is the better choice in this application.

Cheers

John

[AndyfParticipant @andyf]

Andy, in the first reply you received, Chris mentioned this, which might be the easiest way to make a holder to hold a tool at 12° from vertical in two planes.

(another) Andy

PS Anyone know why they are called "tangential"? To me, no part of the tool seems tangential to the workpiece. A 100 year old tome on my bookshelf calls them diamond tools, which describes the rhomboid look of the ground surface as viewed from above.

[Paul LousickParticipant @paullousick59116]

Andy,

The toolbit is tangential to the job. The end of the toolbit is a diamond shape. Hence both names.

[Thor 🇳🇴Participant @thor]

Andrew

I am with John, use steel for the holder. When I made mine I used a steel with about 0.4% carbon, makes the holder a bit harder and can be clamped without too much distortion.

Thor

[Les Jones 1Participant @lesjones1]

Hi Andy & Paul,
Andy, I was about to give the answer that Paul has give but then realised it is not quite true. The axis of the tool will be at about 12 Deg. to the tangent if the tool is at centre height. ( The tangent at centre height will be vertical.) I suppose it is just being pedantic arguing about the 12 Deg.

Les.

[john fletcher 1Participant @johnfletcher1]

I and several of my friends have made Tangental or Diamond lathe tools but have found that when taking large cuts the tool piece has a tendancy to be pushed down. We have tried various screws/bolts to prevent this happening.One might say take more modest cuts,we wonder if some one has a crafty means of tighter clamping. One of us person bought one and I notice there is small protrusion ( little lump sticking out), which I think probably prevents the tool bit sliding down. We are not complaining just attempting to improve things, maybe we are missing some thing.Ted

[John McNamaraParticipant @johnmcnamara74883]

I have a commercially built Diamond tool and have found the clamping adequate I do not use it for deep rough cutting.

For roughing I like to use a negative rake (Carbide) tool bit in a holder.

For finishing to accurate size I prefer HSS tool very slightly rounded as mentioned previously. Finishing to size (to a tenth or two) with carbide is problematic, fine if you hit it in one but carbide due to the rounded edge, on most but not all tips does not like to cut a tenth or two, you get a less than nice finish. You have to cut deeper planning by dead reckoning to finish to size.

Sharp HSS I find is more forgiving, it is happy to peel of a tenth.

Hint use a dial indicator to indicate size, pressed against the cross slide to lead you in to exact size over the last few thou, miking the part after each cut. you may need to make up a jig to fit the dial indicator or use a magnetic base as I do. Unless you are lucky enough to have a digital readout fitted. The cross feed feed screw is out of its depth under .0005. it does not have the repeatability of a .0001" dial indicator.

Cheers

John

[AndyfParticipant @andyf]

Posted by Les Jones 1 on 26/04/2013 08:50:34:

Hi Andy & Paul,
Andy, I was about to give the answer that Paul has give but then realised it is not quite true. The axis of the tool will be at about 12 Deg. to the tangent if the tool is at centre height. ( The tangent at centre height will be vertical.) I suppose it is just being pedantic arguing about the 12 Deg.

Les.

Exactly, Les. If it were truly tangential, the tool would rub rather than cut. But you're right; it was pedantic of me to mention it. Everyone knows what a tangential tool is.

Andy

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