Unimat tools – 6mm or 8mm

[Stuart chugg 1Participant @stuartchugg1]

Would appreciate advice on which tools would be best for my unimat db lathe I have just purchased ?

The tool post will accept 8mm wide tools but 6mm seems to be the most commonly listed tools for it.

Also, would I be better off buying the tools with replacable bits such as ganze please ?

Thank you

Stuart

[Stuart chugg 1Participant @stuartchugg1]

[jason udallParticipant @jasonudall57142]

If you use a 8 mm tool..there is little or no room for “packing” under the tool.
That said a 8 mn section will be stiffer

6mm will (should) be cheaper since there is less material. .per unit length

As to indexable tooling…
Well in theory you are unlikely to work the inserts anywhere near there optimal speeds and feeds .
But when starting out (hobby end after years in industrial turning) I found myself using inserted tooling ..I couldn’t put up with toolgrinding at home.
One thing. I found the “sharp” tool insert geometry usually supplied for aluminium to suit light machines better than those for the 2mm doc of the heavier machines. .
“

[jason udallParticipant @jasonudall57142]

Oh btw.
The reason for “packing” under tools is to adjust the tool height to match the spindles center height…this you will find critical for happy working.
Too low and the part will roll on top of tool.
Too high and tool will rub rather than cut..
Too high is better than too low since under cutting forces the tool will sit down a bit.

[Russell EberhardtParticipant @russelleberhardt48058]

Congratulations on your purchase of a lathe.

That lathe has very low power, about 100 W if I remember rightly, so you need really sharp tools. For that reason I would recommend HSS tools. 6 mm should be more than adequate for such a small machine and are quicker and easier to sharpen than the 8 mm ones. There is 78% less metal to remove when grinding.

Russell

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Russell Eberhardt on 21/06/2016 11:00:32:

Congratulations on your purchase of a lathe.

That lathe has very low power, about 100 W if I remember rightly, so you need really sharp tools. For that reason I would recommend HSS tools. 6 mm should be more than adequate for such a small machine and are quicker and easier to sharpen than the 8 mm ones. There is 78% less metal to remove when grinding.

Russell

I can't disagree with your reasoning except to say that CCGT inserts such as these are sharp and work well on my low powered Flexispeed. I would also agree that 6mm is probably the best size for the Unimat – The difference between the flex of 6mm square steel and 8mm square steel is negligible compared to the other flexibilities inherent in small lathes. In general, I'm of the opinion that trying to fit as big a tool as possible onto a lathe makes for difficulties in installation with no real improvement in functionality ( the situation with boring bars is somewhat different) – but that's just me

Rod

[Brian GParticipant @briang]

Hi Stuart, welcome to Unimat world

I have an SL which is dimensionally identical, and although 8mm tools can be held in the toolpost they will be too high. To set a tool at centre height it must be 6mm oor less. Even with 6mm tools you can have problems as some welded carbide tools have a 6mm body with the tip welded on top, making them nearly 7mm high.

Having said that, you could always use the Unimat to mill a new toolpost to suit 8mm tools, even aluminium will do, or add a quick change toolpost.

Not sure if this is within the forum rules to suggest another site, but the Yahoo group is a great place to find information on DBs and SLs. **LINK** Most members are in the US, but there are a few English speakers in the group – a comment that would make sense if viewing the current discussion there

Brian

[Stuart chugg 1Participant @stuartchugg1]

Thank you all for the most helpful replies and advice – I will buy 6mm.

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