# New style QCTP for an Atlas lathe



## iron man (Apr 7, 2014)

A friend of mine told me I needed a QCTP for my lathe I was raised on the old lantern post and did not want to part with it but he said the I would like one. After looking at the price of a cheap one and a better one I did not think I would like it that much. After some reading I thought I could build one. There are many designs this is one I came up with I started with a 2" x 2" block of CR I bored it for a 1 5/16 brass plug about 1 1/2 long dont expect exact dimensions I just make up this stuff as I go!

I then bored a 3/4 hole through the center after machining a bras plug to fit inside the 1 5/16 bore. This will be for the cam to move it in and out.

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I then setup and started to mill for the dovetail.

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Here i am milling for the dovetails I like milling dovetails in aluminum, brass and even good cast iron but not steel it is very hard on a small machine even with light cuts.

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Just about finised here made it through without destroying the mill or the cutter.

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I chucked up a piece of stress proof and machined an excentric for the ram.

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I then bored a hole through it for the hold down bolt.

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I then knurled a couple of 1/8 pins out of drill rod.

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Here it is with the cam installed it pulls the brass ram in and out very nicely. I then drill a couple holes in the back side of the block into the brass plug this stops the plug from ever rotating even a little the cam stops it but this insures it.

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In order for the center bolt to tighten down without locking the QC handle I had to machine a little hat for it I will show later how this works.

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I then machined the handle for the tool post.

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After some gun blue I got the tool post done I know what your thinking why did I make a piston type?? well its really not the cam pulls the dovetail back locking it firm against the body. It only takes a very small movement to lock it down and it always pulls it straight and consistant. But I am not done.

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Now I start the long task of milling a block to start making the tool holders I should be able to get 5 out of this block. Why five? because I did not have enough material for six.

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This was very hard on a small machine I will do it different next time I will probably remove most of the material with a woodruf key cutter then finish with a dovetail.


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## iron man (Apr 8, 2014)

I could not wait to finish all the tool holders I had to try it and it works great I would not change a thing. I do wish I would have taken more photos during the assembly but it was pretty straight forward and goes together easy. 

As it shows there the tool post is slightly above the bump on the Atlas compound I do not want to mill it off of an all ready weak compound it is setting on a large washer for now but I have plans to modifiy the compound to make it stronger and better but that will come later. All in all it turned out and works very nice the handle is made to come off stem and all very easy incase it gets in the way for any operation. You can see the short slot this is all the movement it needs and it does not even use all of that. So its not a piston or a wedge type I dont know what you would call it but it works real well I still wont give up the stock lantern post it has its place but this was a fun weekend project. Thanks for looking and any comments good or bad.. Ray


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## Smudgemo (Apr 8, 2014)

Nice job, Ray.  Sometimes I think guys like us are nuts.  I've spent quite a few hours making a boring head when I could have bought a new Chinese version for 2x the cost of materials.


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## fastback (Apr 8, 2014)

Nice job on the tool holder.  The pictures were well done also.  So how do you like using a QCTH now that you have one?  To me they are the best thing since sliced bread.

Paul


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## iron man (Apr 8, 2014)

I just made it this weekend so I have only had time to play with it I like how I can take a deeper cut with no chatter and I dont have to see the tool post flex. As far as what the cost vs what I have in it, the materials where free scrap from a friend of mine who owns a machine shop and I consider my time free its mine Ill take it. Its not perfect but everytime you build something you see better ways along the way this one turned out pretty good since I have never seen one like this and I just made it up as I went.. thanks Ray


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## stevecmo (Apr 8, 2014)

Very nice work!!  :thumbsup:  Thanks for sharing.

Somewhere (I'm sure it was here but a search didn't find it) I saw where someone had an alternative to using a dovetail cutter but just using an end mill.  They milled the rectangular pocket with an end mill as you normally would.  Then angled the block and cut the bevel using a smallish end mill.  He ended up with a slight counter bore in the bottom of the bevel which would give a little less contact area but probably wouldn't cause an issue in most cases.  I probably didn't do a good job of describing it but hopefully you can read my mind.  )

Steve


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## iron man (Apr 8, 2014)

Thanks Steve I do remember that thread I was thinking of doing that too except stop shy of plowing a groove through it and then finishing up with a dovetail. Thanks Ray


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## mattthemuppet2 (Apr 8, 2014)

that's really cool, you did a very professional job. This is keeping my "must build a QCTP for my lathe" project at the front of my mind, which is very handy considering how cluttered my mind is!


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## iron man (Apr 9, 2014)

Thanks Matt I made some more tool holders tonight I still have to finish the wedge for the parting tool and drill some setscrew holes in the others.

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 I think I may make some boring attachments next after these are done and are blue'd I cut a small dovetail in the parting tool holder the tool slips right in I will make the lock down next.


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## schor (Apr 10, 2014)

Nice work.


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## iron man (Apr 10, 2014)

schor said:


> Nice work.



 Thanks it was kind of fun.


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## WesPete66 (Apr 10, 2014)

Very nice!
A couple newb questions though.  First, how did you make the eccentric shaft?  
And second, I'm not seeing how the cam functions in the assy. I mean I know the eccentric pulls/pushes the brass shaft. But if the hole is big enough to slip the cam thru, what is holding it to allow it to move the shaft?
Thanks,
Wes


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## iron man (Apr 10, 2014)

WesPete66 said:


> Very nice!
> A couple newb questions though.  First, how did you make the eccentric shaft?
> And second, I'm not seeing how the cam functions in the assy. I mean I know the eccentric pulls/pushes the brass shaft. But if the hole is big enough to slip the cam thru, what is holding it to allow it to move the shaft?
> Thanks,
> Wes



 Yes I should take it back apart and take some more photos. After I bored the hole in the the steel body and brass plug I took a 3/4 end mill and relieved one side of the hole in the brass plug about 1/16"  so as the cam turned in the bore it would not jam. The cam simply pushes to the rear or the front and one side of the 3/4 hole is relieved. As for making the cam I should be telling you I four jawed it and then re-cut it I did not. I put a 1/16 shim under one of the jaws on my 3 jawed chuck I then machined the cam part to 3/4" . I then took the shim out and machined the bearing surface and the top part for the handle it really works good and I dont have to change chuck ( lazy ).

 The top bearing surface is 3/4" OD the bottom of the shaft is 5/8 OD this allows wiggle room to drop the cam in then you install a 3/4 x 5/8 brass bushing in the bottom to fit the bore and make the shaft fit nice and tight to the body. The (hat) at the top allows you to tighten the whole thing down to the compound but the handle remains free. This also stops the cam and the shaft from moving out I sure hope that explains it!! Ray


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