Slitting saw speeds

Hi Paul

Glad to hear you're getting on with the VMC. You didn't say what the material you are cutting is, but when I used a 3" slitting saw in mild steel on the VMC I ran pretty slowly, about 190rpm I think which was as slow as it would go.

I tend to use the formula (CSx4) /D for most purposes on the lathe & mill when using HSS cutters and it works out fairly well.

30mm is quite deep to go with a 3" saw as you will end up pretty close to the arbor so be careful there, and it goes without saying to do it several passes. Also be careful the slot doesn't try and close up on you when you get close to final depth/through depth.

Peter

You won't get 30 mm deep with a 3" saw.

3" is 75 mm so minus 60mm [ 30 each side ] and you have 15 left for the arbor. This won't cover the clamping washers.

To go 30mm deep you need a 4" saw at least. Speeds need to be about 150 max, plenty of oil and if the arbor has a driving key LEAVE IT OUT. Better to allow the blade to slip on the arbor than finish up wearing it. Most times if they snag they either shatter or shear a groove in the key anyway.

Don't ask ...................

If you want to loan a 4" cutter subject to having a 1/16" one I can bring one with me ?

-- Regards,

John Stevenson Nottingham, England.

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In brass, I cut quite quick (about 1000 RPM), but in steel about 200 RPM to make them last longer. It is better to use cooling fluid than cutting oil in steel, to get the chips away. Especially with deep cuts.

28TPI is _very_ fine (not to say much too fine) for that job, be carefull with feeding.

Looking into tables suggests:

80mm diameter steel (mild) min 99.5 RPM max. 198.9 RMP (yes, the number are that precise) brass: 1590..3900 RPM aluminium (cast): 3200..6000 RPM

Ask for different material, but don't ask for the book, it is in German. :-)

Nick

Hi Pete

I`m getting on well with the VMC. I fitted my DRO a while back and have made some simple projects. Also doing a night course on machine shop and feel I may look for a small lathe in the future. Is this a example of Workshopping? The VMC has run really well and I`m very pleased with it.

John, I`m looking to buy a Stub Arbor (R8) and maybe a set (4) of the Arc Euro 3" slitting saws. I have seen them on the web site just thinking you may have taken some to the show? The cut will not have to be 30mm deep - I think actually its nearer to

20mm in EN3A. Will cut in plenty of passes at a low speed and loads of cutting oil. Going to the show on Sunday and hopefully wife will not confiscate my pocket money or plastic this time!

Cheers

Paul

Definitely sounds like the curse of 'workshopping' to me.

I made my own slitting saw arbors when I needed them in a hurry, and they are err.. a bit crude, but work just fine.

Peter

I'll put a set on one side incase they get a rush.

-- Regards,

John Stevenson Nottingham, England.

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John, I'll be at the show on Saturday - could you stick one of the ER32 spin indexers with tailstock aside for me please? Much appreciated if you could.

Peter

Hi John

Woulld be much appreciated if you could save me a set, also the Arbor(R8 1" hole) if you have one. Will be there on Sunday and will call to collect in morning as funds may be low by lunch. Pete, if you had have been there on Sunday I could have put a face to the name - maybe even stretched to buying you a cuppa oh well thats another 50p for workshopping.

Hope everybody has a good time at the show.

Paul