modifiying a right hand toolholder to universal?

[jon hill 3Participant @jonhill3]

Being a bit of a cheapskate and not wanting to buy lefthand insert tool holders,I wondered would it work if the flipside was machined to make the holder universal?

My existing brand insert diamond shaped carbide tool holder does not appear to have any relief angles on the holder.

[jon hill 3Participant @jonhill3]

[Clive FosterParticipant @clivefoster55965]

Theoretically you could but I suspect the screw retaining thread isn't truly vertical. Insert holders tend to have shallow angles that need to be taken into account when rolling your own.

Even if you do it will drive you nuts when you have a job needing both hands.

Sometimes the economy urge is just too economical for sanity.

Clive

[Anonymous]

I'd agree with Clive, a lot of trouble for a bodge result. I've got RH and LH boring bars but I've never needed a LH knife tool. If I did I'd just use one of the boring bars, or grind a piece of HSS.

Andrew

[JasonBModerator @jasonb]

I do have a L/H holder for the usual 2 corners of a CC** insert but it does not get used much, only coming out for the back face of say a flange or the odd time when the compound is set at an angle and that type of tool works better.

I do use a L/H holder that used the other two corners of a CC** insert for facing.

Also have an ambidextrous holder for DC** inserts which is basically what you are proposing that was bought from JB Cutting tools but I don't think they do them now. It mostly stays as R/H but can be handy using both hands to get down the inner sides of things like crankshaft webs

[Howard LewisParticipant @howardlewis46836]

J B Cutting Tools sell such a holder, called, I think, the "Double turn"

Howard

[Neil WyattModerator @neilwyatt]

L/H toolholder set lengthwise at the back of the toolpost has its uses, such as the outer diameter of large discs.

Neil

[Anonymous]

Posted by Neil Wyatt on 03/09/2020 21:13:19:

………………..such as the outer diameter of large discs

LH boring bar works fine and has the appropriate reach:

Andrew

[JasonBModerator @jasonb]

Or for those without a L/H ( standard or boring) tool just turn a R/H one upside down if your chuck fixing allows running backwards.

[SillyOldDufferModerator @sillyoldduffer]

Couple more reasons for not doing it:

• Hard work! My insert holders are all tough hard steel and would have to be ground. Also tricky to make correctly: the holder shape is a precision rhomboid carefully sized and shaped to support the insert. Get it wrong and the insert will flap around under cutting pressure.
• Inserts and holders are one of the most stressed parts of a lathe. Reducing holder strength encourages bending and chatter.

Be suspicious of Universal tools. Tools designed to do one job well will usually outperform a multi-tool: Jack of all trades, master of none.

Much easier to buy an LH insert holder or grind an LH knife from HSS.

Dave

Edited By SillyOldDuffer on 04/09/2020 09:32:37

[old martParticipant @oldmart]

You can easily check if the screwhole is vertical by screwing the screw underneath a couple of turns and eyeing it up. In a tool like yours with a positive insert, the insert is horizontal and the screw is offset slightly so that the insert is pulled tightly into the machined recess when the screw is tightened. Your idea of producing a recess on the other side of the holder has merit, and only the difficulty of small scale precision milling is against it. Most of the common positive inserts have sides sloping 7 degrees and the pocket in the holder has sides to match, that is difficult to reproduce.

Looking at your photos, I see a problem, there will not be much thickness left with such a small tool if there are pockets on either side.

I have machined loads of indexable tools to get them all the same height and can say with certainty that Sandvik, Kennametal, Seco, Korloy, WNT, Mitsubishi, APT, Iscar, Walter and the cheap Chinese ones are equally hard. Not so hard that they cannot be filed or cut with a hacksaw, but carbide tooling is the best way to machine them.

The Chinese toolholders readily available are so cheap, that unless you want to modify your existing one as an exercise, then simply buying a left hand one is best.

Edited By old mart on 04/09/2020 17:56:41

[JasonBModerator @jasonb]

My double sider is 10×10 and I've not noticed any loss of rigidity having the two pockets rather than one. Uses the same screw hole that is threaded right through so assumed straight and I would say the sides of the pocket are also vertical and not angled, I've not seen holders being sold for specific angles of insert.

[Speedy Builder5Participant @speedybuilder5]

It would be a really neat trick if that QCTP holder had a height adjustment on both faces !

[Dave HalfordParticipant @davehalford22513]

Posted by JasonB on 04/09/2020 18:32:10:

My double sider is 10×10 and I've not noticed any loss of rigidity having the two pockets rather than one. Uses the same screw hole that is threaded right through so assumed straight and I would say the sides of the pocket are also vertical and not angled, I've not seen holders being sold for specific angles of insert.

That tip is not so well supported anymore Jason

[Howard LewisParticipant @howardlewis46836]

The holder sold by J B Cutting tools uses CCMT0604 inserts.

Think I got the name wrong, "Two Cut"?

Howard

[JasonBModerator @jasonb]

That one of mine also came from JB but don't think they do them now.

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