Fast Change Rocker Tool Post Holders for the Lathe QCTP

I may make or buy a QCTP for my Sherline in the future but for now I had this idea to use the rocker type tool post on the lathe.
The rocker tool post as implemented on the Sherline will allow easy change out without changing any tool bit height settings.
The rocker can be made with two rockers on one tool holder which improves speed even more. Anyhow that is how I see it so I thought it was worth a try.

Rockers were made on the CNC machine and trimmed by hand with a file.
The main blocks were profiled with the radius for the rocker on the CNC machine.
The holes were drilled on the CNC machine. Center hole was only spotted on the CNC and
then finished on the drill press. This required a .200" hole thru the part to the bottom.
Then the bottom was re-drilled .325" diameter to clear the shaft of the Sherline extended T-nut.
This re-drill stopped .300" from the top of the tool holder.
The holes for the clamping screws were tapped on the bench.
I bought 6 extended T-nuts from Sherline to save a bit of time. Only $3.00 each so my total investment in my QCTP is $18.00.
Should work fine, I made 3 single tool and 3 double tool holders for a total of 9 tool bits.

The black one is the one supplied by Sherline.

Cheers, JR

Very nice, those should work just fine

Those are pretty. I really do like that idea of the individual "Tool Blocks", each with it's own tool all set up and ready to go. You really got me thinking....

I have been toying with the idea of getting a QCTP for my 11" Logan lathe. But cannot justify that cost. It is not much different sliding a "Tool Block" in and out of the slot on the compound rest than it would be on and off a QCTP. I could just make blocks similar to yours that fit my compound. I do not have a CNC to make those curved slots, but I not a fan of rocker type height adjustment anyway. Rocking the tool changes the cutting angles ground on the tool. I long ago replaced the rocker type adjustment on my lantern type tool post with a flat plate. Shims (hacksaw blades with the teeth removed, etc) are used to adjust tool height. The tool slots would just be straight, with tool height set on each block with shims.

Thanks for the idea!!

John

Thanks guys, I also considered the straight slot with shims but went with the rocker type for ease of adjustment. Straight slot tool posts are easier to make without a CNC. The mini lathe is supplied with a 4 tool holder with straight slots. If you make a bunch of short tool bits you can have 4 tool bits at the ready with that design.

Cheers, JR

As a suggestion to those without CNC. Rockers and Posts could be produced via rotary table quite easily.
I start with a bar of flat stock [for either part] and fixture the table to radius one at a time, then 'part off' on a bandsaw. That sacrifices a minimal amount to chips.
Attachment 23531
Mechanically, I'd tend to cut rockers with a slightly larger [.003-.006] radius than tool post to broaden the contact points. Ro-tab or CNC, cut and finish mating faces with same direction.
It also seems logical to use dissimilar materials to avoid galling, if they aren't to be heat-treated.

It strikes me, more practical than seen earlier. Quick Change usually denotes repeatable tool positioning...but unless production is involved that's not a particular advantage.
jjr2001's Quick Change Posts add the modular advantage, a bit more rigidity, flexible setup, and less overhang than any QCTP I can recall. All those are positive features.
I rate better usability for these over import copies of the Aloris without hesitation. Work lathe has a set of those, and don't impress me at all.

Thanks for the tips TM51. I may make more rockers using brass. Meanwhile I will use a small amount of anti-seize on the bottom of the rockers.

Cheers, JR

Nice work again. I remember using a similar type of design on a Myford lathe but the tool had the saddle part machined into the base of the tool and this sat on a mating part for setting the centre height. Not as good as your tool post holders as each time the tool needed changing all settings were lost. I have never seen these tools again, had a quick look on the web but could not find anything like them.

Thanks homeengineer, back in the day when I was in High School my dad (tool and die maker) brought home a 9" South Bend and gave me a few tips on how to use it and not kill myself! I made my favorite stuff back then with it. (Cannons) That lathe had a nice rocker (lantern) type tool post. Worked fine but you always needed to reset the tool height for every tool change.
I like the rocker but wanted to make it "Quick". Maybe I should call this one the QCRP or Quick Change Rocker Post!

Cheers, JR

Quote:

---

Originally Posted by jjr2001

Thanks homeengineer, back in the day when I was in High School my dad (tool and die maker) brought home a 9" South Bend and gave me a few tips on how to use it and not kill myself! I made my favorite stuff back then with it. (Cannons) That lathe had a nice rocker (lantern) type tool post. Worked fine but you always needed to reset the tool height for every tool change.
I like the rocker but wanted to make it "Quick". Maybe I should call this one the QCRP or Quick Change Rocker Post!

Cheers, JR

---

I like it! if I was musical (which unfortunately I don’t have any talent in this field) and I was starting up a band I would now call it “Quick change Rocker Post” sounds really cool
The Home Engineer

The more I think about it (this takes longer than it used to) the more I like your rocker tool posts, It occurs that you could also use them with a small L shaped location plate fixed in your second T slot to give a repeat location function.

Agreeing with olderdan......a locator would make this a real special tool set.
Cost a fraction of commercial QCTP and holders [holders maybe a 1/10th], nearly 100% of the repeatability with some likely advantage[s] over QCTP.

<!-- BEGIN /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->
Thanks jjr2001! We've added your QCTP Rocker Tool Posts to our Lathe Accessories category,
as well as to your builder page: jjr2001's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-qctp-rocker-tool-posts"> <img src="/uploads/213347/homemade-qctp-rocker-tool-posts.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-qctp-rocker-tool-posts">QCTP Rocker Tool Posts</a> <span> by <a href="http://www.homemadetools.net/builder/jjr2001">jjr2001</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/qctp'>QCTP</a>, <a href='http://www.homemadetools.net/tag/tool-post'>tool post</a> </div> </div> </div> </div>
<!-- END /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->

<!-- BEGIN /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->
Thanks Toolmaker51! We've added your Rocker and Post Construction Method to our Machining category,
as well as to your builder page: Toolmaker51's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-rocker-and-post-construction-method"> <img src="/uploads/213352/homemade-rocker-and-post-construction-method.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-rocker-and-post-construction-method">Rocker and Post Construction Method</a> <span> by <a href="http://www.homemadetools.net/builder/Toolmaker51">Toolmaker51</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/tool-post'>tool post</a> </div> </div> </div> </div>
<!-- END /var/www/html/homemadetools/protected/modules/zeus/views/tool/postUpdate.php -->

NICE!!!!! NOW for me to find something like this for the Unimats I have............

Quote:

---

Originally Posted by Hemi

NICE!!!!! NOW for me to find something like this for the Unimats I have............

---

Not to rail on you, but it's called 'Homemadetools.net'.
If you only have a Unimat, I think it could make it's own appropriately sized set.
Any geometry for my rocker concept, could be sketched on paper for scale that Unimat will swing. I wouldn't swing the block. Mount on it's side on cross slide, attach cutter on face plate and figuratively trepan the radius.
Holders are simpler slot milling [rough out via bandsaw] and tapping.
Aluminum 6061 tooling is made and used successfully on smaller [less torque] lathes, maybe have them hard anodized to thwart galling. All in all, I'd opt for one of the various tool steels which may reduce cost to finish.
Many designs retain holders and block, mostly via cam action, but Tee-bolts are used too. Positive location [repeatability] are dovetail or open Vee's. I'd bet partially exposed vertical dowels are possible, otherwise like key ways in a shaft.
Definitely sort of job where only proper tooling will make interchangeable parts; and subsequent repeatability of the holders.

Post here or PM with me, I'll support your project in design and process.

Homemadetools.net......YES.....Super site for all of us with small or large shops. Even a lot of ideas here
that will not require major machinery to make.

I like the idea of the locator for repeatability when installing other tool blocks.
I will need to work on that after "Photo season" is over.

Cheers, JR

More I think about QCTP rocker tool height, the better a center line gauge appears. At the same time, I'll agree that while lantern posts are fully serviceable, they aren't a particularly valued relic.

Your QCTP rocker, a different story altogether. Somewhere I used a post, [4-sided turret] on a full size lathe that was very useful. I could've made a simple T shaped center gauge to sit on top of the compound, but setting with a scale worked fine. Once done, resetting wouldn't usually occur if only front & side relief were touched up. Undo front screw(s) and remove bit. Grind and remount, back screw is still going to reference previous setting.
For QC's, a very simple plate and T can set-up off machine. Even now, despite insert or brazed tooling, I use HSS very often, to get the surface finish RMS when and where I want it. Don't get me started on form tools; much more complicated process and $$ in carbide!

Naturally, carbide has it's place. HSS isn't so over the counter anymore. For HMT'ers that might be a detriment. Even in commercial shops, offhand tool grinding is a seldom practiced art, they'll just throw in another insert.
A few days ago I sleeved a pair of cast iron trunnions for new bearings. I rough bored them fast with carbide, then took my time with a plain bar holding a 5/16" square bit ground to a modified turning profile [a lot of clearance]. 2 passes got an engine quality bore, cylindrical - straight & consistent surface within tenths of ideal size. My super carbide bar wouldn't have done as well.

I went with a similar idea for my Proxxon lathe. Commercial QCTP's were either too large or way too expensive given how rarely I use the little lathe. I milled out a couple of aluminium blocks on the lathe itself. It works well.