QC tool posts

Hi guys, I am an old newbie in need of some help.

I don’t have a history in turning but a year ago I bought a small secondhand metal turning lathe, I found it very interesting to use and I have started to understand what I could do on it. But I soon outgrew it and bought a new bigger one, I bought a “Crenex 220 x 600mm” (yes I know) I already knew that it would come with problems, probably more than I expected but I have spent quite a bit of time resolving most of them.

What I need advise about is buying a QC toolpost, I equipped my old lathe with one and found it excellent, now I want one on the new one I want one which takes 16mm (5/8&rdquo tools. I keep looking at the 250-200 with 200 series holders but according to the description it is for a 10 to 15” spin, my lathe is just over 9”. Can anyone advise me whether I can get away with this, Longbow sell it but will not respond when I asked for help.

Any help please would be appreciated, Roy

Hi Roy,

Welcome to the forum. Measure the distance from the topsiide (compund) to the lathe centreline and compare to the disthorance from the bottom of your 5/8" tool to the cutting edge. On my lathe the difference is just over 9mm, but I use 13mm (1/2" ) tools. Are you sure your lathe is designed to take 5/8" tools?

Thor

Edited By Thor 🇳🇴 on 01/02/2022 07:44:18

As Thor says why do you need to use 16mm tools on a hobby lathe, I have a 280 x 700 and the largest I tend to use 10mm

Why not contact the supplier and see what they recommend as being suitable for this machine, most reputable ones usually list toolposts for each machine. Failing that find a reputable supplier of a similar machine and go by what they suggest.

Hi Roy,

I use the 100 series toolpost and holders on my Boxford 10-20 lathe, 11 inch swing. They take up to 14mm shank tools. The toolpost model I have is the 111 which you can find on the Arc Euro website with all the dimensions. The purists may tell you that the 111 (wedge) type toolpost gives better repeatability than the 100 (piston) type. Whether that will affect your work only you will know....

The problem you may have with the larger toolpost is not being able to get the tool low enough to be on centre height. Again, the Arc Euro website gives details of how to determine this, also mentioned by Thor above.

No connection with Arc, etc.

John

Good morning Thor, good morning JasonB thank you both for your replies it is appreciated.

its not so much the size of the tool as much as wether I can use the QC 250-200, the current fixed toolpost which came with the lathe is a 16mm holder and a 5” chuck so I bought 16mm tools for it and since they were not cheap I do not want to discard them.

However having revisited the situation and reading your comment about why do I need 16mm tools on a hobby lathe, I think I will modify the toolpost site and use my original 250-000 which I have a full set of QC for, thank you, your comments did definitely help.h

What I save on the new toolpost will buy new tools, and I can use the 16mm if needed in the old holder

It’s good to have friends. Warmest regards. Roy

Thanks JohnC, much appreciated for your reply, and the pointer to Arc EuroI know where I am going now.

regards Roy

Maybe he wants to use 16mm tools? The advice very often touted about machine tools is to buy the biggest you can as they are more solid. Same with tool bits. If you can afford the bigger ones no reason not to use them. I have a 8 1/2” x 14” lathe and generally use 12mm tool holders but I also use 16mm ones cut down to 14mm to suit my tool post. For some of the triangular inserts I use (very economical as you get 6 tips) I don’t think you can even buy a tool holder for them smaller than 16mm. Small tools are fine for many jobs and can get in tighter spaces but no reason not to use the larger ones either. A quick look on the auction site indicates you can still get them for about a tenner.

Hello again guys, I have now modified things so I now have the QC post from my original lathe and all works well I have 10mm bits that I use in it but when I have to replace them I will upgrade to 12mm, my old QC will allow this. I can also easily change back to the larger QC if I want to very easily.

I only bought the 16mm tools because I was (and still am) ignorant of what I needed, and as the new toolholder that is original to the new lathe and as it was a 10mm toolpost I thought it dictated using the larger tools.

On my old lathe I bought 8mm then 10mm tool bits but of course I kept having to shim up with both sizes and was pleased when I found out about QC and why I thought it would be good to do the same on this new lathe because I still have to shim up the 16mm tools only a thin amount but still annoying. I do agree I like the bigger tools because as Vic says the small sizes are not very strong and with the 8mm I was ever knocking the cutting edge off, I know it’s because of too fast feed but as I said at the beginning this is all very knew to all this and had no-one to turn to for help, I am learning slowly.

thanks everyone. Roy