Fast Change Rocker Tool Post Holders for the Lathe QCTP

[Toolmaker51]

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.

[DIYer]

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:

QCTP Rocker Tool Posts by jjr2001

tags: QCTP, tool post

[DIYer]

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:

Rocker and Post Construction Method by Toolmaker51

tags: tool post

[Hemi]

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

[Toolmaker51]

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.

[jjr2001]

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

[Toolmaker51]

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.

[Rorschach]

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.