QCTP for chester lathe

[Chris12Participant @chris12]

I bought a chester lathe (DB8VS) and would like to have a QCTP on it. I bought from ARC a wedge type QCTP, however it doesnt fit the machine, as my top slide has a spigot with a diameter bigger than the bore of the QCTP.

 

I dont think filling down the spigot is a good idea, as i believe it is here for a good reason (rigidity ?).

 

I cannot enlarge the bore of the QCTP, as the spacer (pic below) is where the pressure is applied from the top of the QCTP to the bottom. I machined a replacement one, without the bottom thread, and realized that was not an option.

So I think this QCTP will simply not work and will have to go.

 

Looking at other options, I came accross 2 types :

 

– Dickson type

Soba 5pc Quick Change Toolpost compatible with Myford ML7 etc

it seems that boring the bottom to accomodate the spigot is an option, however the tool post is hardened, so it might prove tricky.

 

– Multifix type

Multifix Style 40 Position Quick Change Toolpost 150 – 300 Swing

these have a bore that would readily accept the spigot, so no machining of the QCTP seem necessary. However, this type is very pricey…

 

Considering the price, I would rather go the dickson type, with the condition that it can be machined and it performs satisfactorily (i recall reading some negative stuff about it some time ago)

 

Any advise or comment are welcome !

 

[PeteParticipant @pete41194]

There’s numerous YouTube videos showing what was done to adapt top slides like you have to what the tool post might need and what not to do.

[Stuart Smith 5Participant @stuartsmith5]

Can the existing spigot not be removed ? And then a replacement made or the new supplied one modified?

I had to do this to fit the Arceurotrade one to my Warco lathe.

I think the original spigot was push fit from below and I removed it and made a bush to fit the hole and spigot from the new QCTP.

Stuart

[Chris12Participant @chris12]

No, the spigot is part of the top slide, so if I remove it I won’t be able to put a new one in place.

[Stuart Smith 5Participant @stuartsmith5]

Chris

I have added a couple of photos and some more info to my post

Stuart

[Stuart Smith 5Participant @stuartsmith5]

I think the original spigot was push fit from below and I removed it and made a bush to fit the hole and spigot from the new QCTP.

[Howard LewisParticipant @howardlewis46836]

Are you really desperate to have a QCTP?  Or is it a “nice to have”?

Fitting one, always seems to require modifications to the lathe, or the post.

From what i hear, changing tools (Unless changing a large number and very frequently) once set, three tools in a four way is no slower. (I have the choice of six, having made a four way rear post.  So rougher, finisher, boring, in front, with front and back chamfer and parting tool in the rear toolpost)

Possibly, given more thought, it may even be possible to fit four into each post.

As hobbyists, we are very rarely having to work against the clock, so time is not of the essence.

Howard

[Stuart Smith 5Participant @stuartsmith5]

Chris

I have found some photos I took when I was doing mine.

The first photo is of the underneath of the top slide with the original bush/ spigot removed. The second photo shows my replacement fitted. I remember now I had to tap it to screw the new piece in. The third photo is from above with it fitted.
Stuart

[Stuart Smith 5Participant @stuartsmith5]

Howard

I have found it very useful.

Stuart

[Chris12Participant @chris12]

Thanks Stuart. The stud can be removed from below the top slide. However the spigot is an integral part of the top slide (from the picture it looks like it is a separate part, but it is not). Also, the diameter of the spigot (20 mm) is bigger than the bore of the QCTP (14 mm).

I considered filling down the spigot to reduce its diameter to the QCTP bore (ie 14 mm) but that means the thickness will only be 2 mm (the existing stud is 10 mm).

 

[Chris12Participant @chris12]

Hi Howard,

 

not desperate, rather nice to have. IT’s a bit of a pain to change the tools with all the different spacers. Much more convenient to have a QCTP. I know some people are against it, but I think it’s a nice improvement to have.

[Howard LewisParticipant @howardlewis46836]

Agreed that a QCTP can be useful, in that if changing tools frequently you have a tool that is set for height.

I considered one, but having for every turning tool that I MIGHT want to use would need a lot of space, (that is not available).

As it is, once set, for most of the time, (using a packer rather than a great pile of shims), unless knurling or radius turning, or doing something a little unusual, for the last 21 years the two four ways have met my needs.

But each to their own.

Howard

[Richard SimpsonParticipant @richardsimpson88330]

I’m not sure if you would be interested in dealing with a supplier in the USA but I bought my own QCTP from these guys for my Chester lathe many years ago.  There was no modification to the lathe required, it was simply a quick exchange.

https://littlemachineshop.com/products/product_related.php?RelatedID=2131530750

As supplied:

As modified:

If you are interested I can try to dig out the exact model I bought.  Obviously shipping will be high but there is a significant saving in the cost of the unit to offset it.

[Howard Lewis]

On Howard Lewis Said:

Are you really desperate to have a QCTP?  Or is it a “nice to have”?

Fitting one, always seems to require modifications to the lathe, or the post.

From what i hear, changing tools (Unless changing a large number and very frequently) once set, three tools in a four way is no slower. (I have the choice of six, having made a four way rear post.  So rougher, finisher, boring, in front, with front and back chamfer and parting tool in the rear toolpost)

Possibly, given more thought, it may even be possible to fit four into each post.

As hobbyists, we are very rarely having to work against the clock, so time is not of the essence.

Howard

Agreed. I have a 8 1/2” X 14” lathe and it’s not exactly that rigid to start with. I use mainly a Tangential tool which has built in height adjustment or carbide tooling. For the carbide I have either trimmed the holder to put the tool permanently on centre height or epoxied a shim on the bottom of the tool. A four way tool post works well for me and is just as quick in many cases, not that speed of tool changes is an issue as a hobbyist.

[Chris12]

On Chris12 Said:

Hi Howard,

 

not desperate, rather nice to have. IT’s a bit of a pain to change the tools with all the different spacers. Much more convenient to have a QCTP. I know some people are against it, but I think it’s a nice improvement to have.

If you intend to use carbide tooling then you only need to “shim” or adjust the tool once to fit a four way tool post. Once it’s glued or screwed in place it will never need to change and the setup will be much more rigid than a QCTP. Your choice but a QCTP is not an improvement, just an option. Look at all the CNC lathes, they don’t have them.

[JourneymanParticipant @journeyman]

My WM250 had a spigot on the top-slide but removal has made no difference to the lathe operation. Have a look at Journeyman’s Workshop for a detailed (two page) description of what I did.

John

[dk0Participant @dk0]

Chris, I’m designing a “hybrid” QCTP.
The function is that the tool is mounted in its seat, then the entire tool holder is applied to a column fixed to the carriage. The tool holder is locked onto the column by the cross-tightening screw and when you want to change the tool, you replace the entire tool holder.The height of the tool/tool holder is adjusted with the usual knob screw.
This system is suitable for mini lathes like yours or Hobbymat, etc. If you think it’s a good solution, I’ll make a prototype and send it to you free of charge,just a feedback on its operation. Please let me know.

[Chris12Participant @chris12]

Thanks John, very informative. I don’t have enough swing to machine the top slide in the lathe, so it will have to wait until I get a mill. But good to know that removing the spigot hasnt had any detrimental impact on the lathe performance.

[Chris12Participant @chris12]

Thanks Richard. But I think the mini-lathes have a small spigot, this the qctp fits directly. The qctp from little machine shop are similar to the one I bought at ARC.

[MarkSParticipant @idriver]

I bought the DB10VS and sure enough that too has the same spigot on the top slide 🤬. I am just in the process of removing the whole top slide assembly and replacing it with a solid block to hold the QCTP. Purely coincidental but it is very similar to what John (Journeyman) did, (see his link above). On the odd occasion you do need a top slide it’s a case of slacken off the mounting bolts and swap back to the top slide.

[dk0Participant @dk0]

I’ve cut some QCTP/TH (tool post/holder) with EDM because I think it’s a simple, practical, and economical solution for mini lathes. I’ll let you know the results of the test!

[FulmenParticipant @fulmen]

Very nice, you could even make it indexable like the MultiFix without too much modification.

[dk0Participant @dk0]

Yes, I’ve already included three index positions: 0°, 45°, and 90°, with a 5mm pin and three seats on the body.

Thanks for the encouragement, and any other suggestions are welcome.

[BazyleParticipant @bazyle]

DK0 this is like the Drummond Norman toolpost. If you made yours compatible it would be useful for anyone with that style.

For smaller lathes there is the Archibald QCTP. kits from Hemingway. Advantage of own choice of mounting hole size and more holders are just small bits of steel bar, 1x 1.25.
https://www.hemingwaykits.com/HK1100

 

[dk0Participant @dk0]

Yes, to be honest, I got the idea from an Italian tool post that I thought was the original, but in fact it was copied from the Drummond Norman tool post.

I simply stylized it and made it more ergonomic,I still think it’s a good and practical solution.
Thanks, Bazyle, for the link and suggestions.

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