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Tool post project

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Juddy05/09/2019 12:39:18
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61 forum posts

I made one of these and 10 tool holders: **LINK**

works very well both on an Altas and latterly a Boxford AUD.

Laurent VIDAL05/09/2019 13:30:18
2 forum posts
Posted by JasonB on 05/09/2019 08:59:28:

most of the cutting force going into the tool is downwards so you will not get as good support than if the tool were sitting on a solid holder.

the screw will need to be inset from the end of the holder you will effectively get more tool overhang so less rigid and more prone to vibration.

tip heights can vary with inset tools and if using HSS or brazed carbide the cutting edge will not be at the top of the tool but lower and you would not be able to raise this if the top of the clot was on CTR height.

Edited By JasonB on 05/09/2019 09:00:49

Very good points! Did not think of these... Thanks Jason!

Posted by ChrisB on 05/09/2019 07:53:27:

Noticed it's your first post, welcome to the forum Laurent!

Edited By ChrisB on 05/09/2019 07:59:09

Thank you Chris!

Neil Wyatt05/09/2019 14:04:53
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Moderator
16585 forum posts
687 photos
75 articles

I wonder if you could arrange to have two circular wedges. One would be loose on toolpost and sit on the top slide, the other would be above it and keyed to the body of the toolholder.

This could raise a platform to secure the tools in place as Laurent suggests, without any loss of rigidity. A pair of linear wedges could work even better but be less elegant.

Neil

ChrisB05/09/2019 14:58:10
401 forum posts
162 photos
Posted by JasonB on 05/09/2019 08:59:28:

Chris, I would have thought it quicker and less of a fiddle to just unwind the handle a couple of turns rather than faff about with the "C" washer. You could still retract the holder towards you once the plate is high enough to let the holder move sideways enough to let the lip clear the main block.

One other thing have you checked how much support the holder has for the odd occasion when the toolpost needs to be angled as there will be nothing under the holder ends when at 45deg

Yes Jason, at 45deg, the tool holder will have less support as you pointed out. I calculated the bottom support surface area will decrease by 28%. But, as the top plate applies force to the tool holder at 45 deg (via the wedged top plate ends) , this should result in the tool holder being pushed both down and towards the tool post body. In other words the tool holder is supported both from the bottom and back faces... right? So I suppose the loss of rigidity will not be so much noticeable - I hope!

Regarding tool post entry and exit routes,I could take the top plate off as suggested, or use cam lever (not sure if clamping force of a cam is comparable to that of a fine thread). But I have (yet!) another design in mind - to the drawing board for design no....4, or was it 5..!

ChrisB05/09/2019 20:13:46
401 forum posts
162 photos

This the latest amendment to the plans to allow for releasing the tool holder to the side, and without removing the top plate off.

Added three tenons to the tool post block which will engage in slots on the tool holder. This will locate the tool holder for repeatability and prevent the holder moving rearwards.

The top plate wedge and tool holders are slotted with matching grooves. The idea is that to release the tool holder, I release the threaded handle ( half a turn maybe) and slide the top plate rearwards ( the plate centre hole is slotted to accommodate for this). When the top plate slides back the tool holder is disengaged from the "teeth" on the wedge and can slide to the side.

tool post 9.jpg

I guess it's not easy to explain but hopefully the drawings can make better sense...or not!

The below drawing shows the tool post in the closed and tool engaged position (left). Unlocked and tool disengaged position (mid) unlocked and tool exit to the side (right)

tool post 8.jpg

Nicholas Wheeler 106/09/2019 00:29:10
275 forum posts
16 photos

I think you've gone backwards: that's added a lot of extra machining to each toolholder - you need a lot of them, so that's important - that doesn't justify its existence. That's why I like John Stevenson's suggestion to reverse the dovetails on a more traditional style post, and put the male dovetail on the holders.

thaiguzzi06/09/2019 06:01:50
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575 forum posts
131 photos

Way over complicated.

The whole point of making a QCTP and holders is you make the complicated post once, and the easy (easier) to machine holders multiple times.

A la Dorian/Aloris type clones.

I'm not one to talk because i have (19) and machine Dickson clone holders....

Again, have a look at the American MLA 23 design, so so simple, yet so so effective, and easy to put a location function in if required.

20160830_134415.jpg

bricky06/09/2019 08:22:01
378 forum posts
47 photos

p1040176.jpgThis is my toolholder based on the Pratt-Burnerd design p1040179.jpg

Graham Meek06/09/2019 10:00:21
114 forum posts
117 photos

This is a solution I made in the late 1980's before going back to a 4 Tool Turret, based on George Thomas's design.

fig 1 homemade interchangeable tooling.jpg

fig 8 dis-assembled interchangeable tooling.jpg

Regards

Gray,

Alan Jackson06/09/2019 11:17:00
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167 forum posts
67 photos

I agree with Thaiguzzi's comments on the MLA Toolpost. Here is my version with the cutting tool within the envelope of the Topslide and Cross slide for maximum rigidity.

Alan

close to the tailstock.

new topslide.jpg

Russell Eberhardt06/09/2019 11:20:40
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2484 forum posts
85 photos
Posted by Nicholas Wheeler 1 on 06/09/2019 00:29:10:

I think you've gone backwards: that's added a lot of extra machining to each toolholder - you need a lot of them, so that's important - that doesn't justify its existence. That's why I like John Stevenson's suggestion to reverse the dovetails on a more traditional style post, and put the male dovetail on the holders.

Agreed. I made one to his design but enlarged a little for a 5" lathe over ten years ago and have been very happy with it. Other than the ease of making the holders it has the advantage that two holders can be fitted at right angles to each other. I would post a photo but both my camera and phone have flat batteries at the moment.

Details of the design are still on line here.

Russell

Michael Gilligan06/09/2019 11:28:35
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14024 forum posts
609 photos
Posted by thaiguzzi on 29/08/2019 14:24:28:

IF i was making a new QCTP system, without a doubt i would copy or make my own version of the MLA-23 toolpost.

Google it.

Nicest QCTP i have seen. IMHO. Extreme simplicity, extreme rigidity.

.

Thanks for the reference ... I don't think I had seen that before

Here, for the Goog'ly-challenged, is a useful **LINK**

https://www.practicalmachinist.com/vb/south-bend-lathes/machining-mla-23-toolpost-174336/

MichaelG.

Phil P06/09/2019 11:29:53
510 forum posts
137 photos
Posted by Graham Meek on 06/09/2019 10:00:21:

This is a solution I made in the late 1980's before going back to a 4 Tool Turret, based on George Thomas's design.

fig 1 homemade interchangeable tooling.jpg

fig 8 dis-assembled interchangeable tooling.jpg

Regards

Gray,

Gray

I still use mine on the Super 7, its a brilliant design in my opinion, why did you revert back to a four way toolpost ?

I made Georges four way turret years ago, but did not really like it to be honest.

Phil

Edited By Phil P on 06/09/2019 11:31:07

Graham Meek06/09/2019 13:07:49
114 forum posts
117 photos

Hi Phil,

Hope you are well. and glad to hear my tooling is still working well.

The reason I changed to GHT's Turret was based on problems I was having keeping my own Interchangeable Tooling free of very small bits of Brass swarf. These bits of swarf were making it impossible to hold some very tight tolerances on a commission I had undertook.

I had always though my original design was easy to keep clean, up until this point. With only 4 faces to keep clean. The prospect of another larger batch commission meant something had to give. I had always promised George I would give his turret a go one day. One thing that had put me off before hand was packing. However I think I have managed to work out a system that does not need packing.

By the way the larger batch was done much quicker than the original smaller batch. The Turret got left on the machine and my interchangeable system was sold.

I have added recently a refinement to the original design in that the Turret is now self indexing, but as yet I have no photographs of this. Those who have seen it think it warrants an article, but we shall have to see on that.

4 tool turret on maximat lathe..jpg

Note how there is no chance of swarf to get into the location slots.

fig 6 dis-assembled maximat turet.jpg

fig 7 associated maximat tooling.jpg

What is not shown in the above photograph is the register pins beneath the tool holders. One such pin can be seen in the top of the second standard tool holder. I now have dedicated insert tool holders again with registration pins. Thus I have the advantages of both systems.

Regards

Gray,

thaiguzzi07/09/2019 10:34:35
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575 forum posts
131 photos
Posted by Michael Gilligan on 06/09/2019 11:28:35:
Posted by thaiguzzi on 29/08/2019 14:24:28:

IF i was making a new QCTP system, without a doubt i would copy or make my own version of the MLA-23 toolpost.

Google it.

Nicest QCTP i have seen. IMHO. Extreme simplicity, extreme rigidity.

.

Thanks for the reference ... I don't think I had seen that before

Here, for the Goog'ly-challenged, is a useful **LINK**

https://www.practicalmachinist.com/vb/south-bend-lathes/machining-mla-23-toolpost-174336/

MichaelG.

Yes, Paula always wrote and photographed wonderful write ups for the South Bend forum on PM. Her SB 9A was a fantastic resto, stunning lathe.

As Alan above states, the thing is so rigid, because there is no overhang. I also prefer the looks of his done in round rather than square stock. The guy who invented it, describes the toolpost as a QC Lantern. All the advantages of both with none of the disadvantages of either.

And easy to make.

thaiguzzi21/09/2019 07:41:59
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575 forum posts
131 photos

Bump.

Wonder how the OP was getting on?

If he had taken on any of our ideas or suggestions or was ploughing along with his own plans?

ChrisB21/09/2019 08:56:41
401 forum posts
162 photos

As I mentioned before I appreciate ALL feedback given and thank you all for that.

The "ploughing" comment is maybe a bit out of place imho, I cannot implement all the suggested ideas into a single design so I might have some preference of one design over an other.

Chris

ega21/09/2019 09:19:06
1267 forum posts
108 photos
Posted by Michael Gilligan on 06/09/2019 11:28:35:
Posted by thaiguzzi on 29/08/2019 14:24:28:

IF i was making a new QCTP system, without a doubt i would copy or make my own version of the MLA-23 toolpost.

Google it.

Nicest QCTP i have seen. IMHO. Extreme simplicity, extreme rigidity.

.

Thanks for the reference ... I don't think I had seen that before

Here, for the Goog'ly-challenged, is a useful **LINK**

https://www.practicalmachinist.com/vb/south-bend-lathes/machining-mla-23-toolpost-174336/

MichaelG.

Thanks (yet again) for the link; I find yorkers difficult, too!

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