Gloster tools make a QCTP in alloy, I've never used one but they have been selling them for a long time.

Unlike Norman's picture above it is more common to have the block rotated 90 degrees clockwise from as shown so that one mounting is close to the lathe centre line for holding a boring tool or combined facing and chamfering tool. As every tool becomes expensive to mount it is worth thinking whether you can combine them and also use the other end by using long toolbits.

A QCTP is not just for setting centre height. As they mount repeatably in the same place this is also in the same place relative to one another which you can use to advantage. Use a cranked right hand knife tool if possible so that its cutting point is exactly in line with the facing tool so after facing you do not need to reset your reference for the new tool. Then set the parting / grooving tool left hand front and edge to align with the knife too. Finally align your screwcutting tool for matching depth.

So for example you can face off, cut a length for threading then go straight in with the groove for screw cutting tool clearance, then switch to screwcutting all aligned to each other.

Finally if you set the cross slide index on zero with the tool on a known round figure diameter, eg 1/2 in and don't fiddle with it you know it will be at zero when dead centre. Then you can cut close to required size on the dial and only check for the final precision cuts.

Well spotted Vic! I have another QC tool post that mounts on the back of the (long) cross slide and the "upside down" parting tool is fitted there. Parting is thus achieved by "withdrawing" the cross slide. Having parted off then the conventionally (front) mounted tool can be used for the next item. (Tool post, holder and blade were purchased )

Bazyle yes I agree it is more usual for it to be positioned 90 deg C/W but this photo was taken for a thread many many posts ago just to demonstrate my (bodged up!) mounting for a dti for setting up 4-jaw work.

As to "economising" on the number of tool holders yes you have a point but having the tool you need ready mounted saves time and frustration.

Norman

Of course you will sometimes also want to set it as Norman has for getting to the outside of a flywheel for example.

That DTI mount is neat and could be a dual use holder by putting a boring tool in the holder having the DTI bracket acting as packing for said tool.

Arguably one of the best types of QCTP is the type shown in Normans picture. These were originally made by Dickson but others have copied the design and some are even interchangeable. The tool posts themselves are available in quite a range of different sizes to suit different Lathes.

http://www.myford.co.uk/acatalog/Myford_Quick_Change_Toolpost_and_Accessories.html

Just one supplier, Chronos also sell something similar.

Edited By Vic on 23/12/2015 21:57:09

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Tim,

I am ready to be proved wrong, but; I think you will find that pushing loose-fitting male/female dovetails into engagement [by pressure at about the mid-point] will automatically centralise them … It would be worth doing a few practical tests on your QCTP.

MichaelG.

Quite right!! I have 23 or 24 and am planning more!!

cheers

Bill

Dickson tool holders often sell for around £20 second hand at the shows. No idea what the posts cost though.

Chris, if it helps Chronos are doing Myford size Soba holders at about £11 at the moment in 5 off quantity. Haven't tried one for fit yet but the post was from the same source so interchangeability should be less of an issue. An interesting point in a way as I've never thought of bluing one to check on contact area.

BTW not advising it necessarily but I use a Myford size on a 4 1/2 Boxford on a 1/4 raising plate. At the time I didn't have anything to compare so did not know I had been given the wrong size until I came to buy more holders. At least it makes the holders cheaper and I'm not making parts for battleships anyway so plenty rigid enough.