# Doesn't exist? -- 8 TPI threaded chuck to fit an 80mm HF faceplate (w/ picture)



## bcrimmins (Jan 26, 2022)

I have searched and searched... and searched -- Google, Amazon, Ebay. I cannot find a source for an 8 TPI threaded chuck to fit my 80mm HF faceplate. It's bizarre.  Here is a 3d rendering of what I'd hoped to find. Has anyone seen a real-life version of one of these? It seems like it would be a super useful mod for HF mini lathe owners but apparently I'm the only one who wants one???


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## DavidR8 (Jan 26, 2022)

What diameter is the threaded portion?


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## Al 1 (Jan 26, 2022)

That's the same thing I was thinking.


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## bcrimmins (Jan 26, 2022)

DavidR8 said:


> What diameter is the threaded portion?


The standards are either 1" or 1.25". I'd take either one!
The threads are 8 TPI.


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## RJSakowski (Jan 26, 2022)

That looks like a strange configuration.  What is the model no. of the lathe?


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> The standards are either 1" or 1.25". I'd take either one!
> The threads are 8 TPI.


An issue with what the drawing that is shown is that a chuck that screws on to it won't allow stock through it.  My mini-lathe has a spindle bore of 20mm, which I have used that way a lot.  Are you having issues with sourcing a new chuck?  What's the motivation for having such a unicorn?


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## bcrimmins (Jan 26, 2022)

RJSakowski said:


> That looks like a strange configuration.  What is the model no. of the lathe?


My lathe is the HF 93212. That picture is just a sketch of roughly what the relevant chuck would look like... if it existed.


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> An issue with what the drawing that is shown is that a chuck that screws on to it won't allow stock through it.  My mini-lathe has a spindle bore of 20mm, which I have used that way a lot.  Are you having issues with sourcing a new chuck?  What's the motivation for having such a unicorn?


Yes, that picture is just a sketch of roughly what the relevant chuck would look like... if it existed. For sure, you'd hope that the real unicorn would have a pass through. 

The motivation is to support the plethora of alternative chucks that are available but are only designed to fit on a threaded spindle. To wit, this ring mandrel chuck.


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## WobblyHand (Jan 26, 2022)

Ok, now we can see the motivation!  Presuming that your lathe has a taper.  Aren't there similar ring mandrels that use a taper instead?  Perhaps you could make one?  Or use a straight shank mandrel in a MT2 chuck?

How about this one?  MT2 expanding ring mandrel


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## Aaron_W (Jan 26, 2022)

I'm also kind of surprised there are no threaded adaptors for the flange mount lathes. 1"-8 and 1.25"-8 are common wood working lathe spindles, 3/4"-16, 1"-10 are common small metal lathe spindles (Sherline, Taig, Atlas/Craftsman 6"), 1.5"-8 is common on 9-10" lathes. 

That would certainly open up a ton of tooling options for the 7-11" import lathes that usually have the flange mount.


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## DavidR8 (Jan 26, 2022)

I expect that you need a 1.5x8 thread to fit threaded back chucks. That said, those are not all that common in sizes that will fit a 7X lathe.


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> Ok, now we can see the motivation!  Presuming that your lathe has a taper.  Aren't there similar ring mandrels that use a taper instead?  Perhaps you could make one?  Or use a straight shank mandrel in a MT2 chuck?


Indeed there are taper-based ring mandrels. Pretty sure I've looked at every mandrel on the market. For design, functionality and price... this one just happens to be my choice. I was shocked that I couldn't just go to ebay and buy a threaded spindle chuck! There are a ton of faceplate-mountable threaded spindle chucks... that are the female type -- but no male type!!

BTW, I considered just throwing the ring chuck in the jaws but I suspect precision alignment will be a hassle... every single time I use it. 

I also considered mounting a spindle adapter like this in the jaws. But same concern.


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> Indeed there are taper-based ring mandrels. Pretty sure I've looked at every mandrel on the market. For design, functionality and price... this one just happens to be my choice. I was shocked that I couldn't just go to ebay and buy a threaded spindle chuck! There are a ton of faceplate-mountable threaded spindle chucks... that are the female type -- but no male type!!
> 
> BTW, I considered just throwing the ring chuck in the jaws but I suspect precision alignment will be a hassle... every single time I use it.
> 
> ...


The morse taper mandrels will run true.  Remove your chuck and seat the mandrel tool into the taper.  No fiddling, no adjustment.  Works every time.  You will have to drive out the taper when you are done, just use a soft metal rod, like aluminum.  A tap ought to do it.

Or you could make a super mandrel of your own.  If I was you, I'd try the taper one first.


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## Aaron_W (Jan 26, 2022)

DavidR8 said:


> I expect that you need a 1.5x8 thread to fit threaded back chucks. That said, those are not all that common in sizes that will fit a 7X lathe.



No but it could be useful on a 10x22" which also commonly uses a flange. Apparently the flange adaptor for plain back chucks can be hard to obtain, and not that cheap. Somebody was recently going to a lot of effort to get one for a PM1022. A 1.5"-8 adaptor would open up a huge range of new and used tooling.


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## DavidR8 (Jan 26, 2022)

I don't believe that lathe has a MT spindle so not sure how an MT taper rink mandrel would be.
Unless I'm lost in translation which is entirely possible!


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## RandyWilson (Jan 26, 2022)

The Sieg 7" Minila The series does have an MT3 spindle.


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## DavidR8 (Jan 26, 2022)

RandyWilson said:


> The Sieg 7" Minila The series does have an MT3 spindle.


Classic!
I looked at the specs and saw the tailstock is MT2 but there's no mention of headstock taper only the bore of 5/8"


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> The morse taper mandrels will run true.  Remove your chuck and seat the mandrel tool into the taper.  No fiddling, no adjustment.  Works every time.  You will have to drive out the taper when you are done, just use a soft metal rod, like aluminum.  A tap ought to do it.
> 
> Or you could make a super mandrel of your own.  If I was you, I'd try the taper one first.


Thanks, yeah, I've looked at all (I think) of those but I don't like them as much. They are really common for pen turning and often just an adapted pen mandrel. If necessary, I might end up there... but I really like the design of the spindle version.


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## WobblyHand (Jan 26, 2022)

DavidR8 said:


> Classic!
> I looked at the specs and saw the tailstock is MT2 but there's no mention of headstock taper only the bore of 5/8"


Just looked at the docs on the lathe, no mention of spindle taper!  

My mini-lathe is from Little Machine Shop and made by Sieg (for LMS).  It has a MT3 taper in the spindle and a 20mm spindle bore.  I'd check the spindle for evidence of a taper.


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## RandyWilson (Jan 26, 2022)

DavidR8 said:


> Classic!
> I looked at the specs and saw the tailstock is MT2 but there's no mention of headstock taper only the bore of 5/8"




Yeah, I don't see it in the specs. My HF 7x12 spindle is MT3. Littlemachineshop shows that 7x10 to also use a MT3 spindle. But the 5/8" through-bore is the specs is very odd.


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> Thanks, yeah, I've looked at all (I think) of those but I don't like them as much. They are really common for pen turning and often just an adapted pen mandrel. If necessary, I might end up there... but I really like the design of the spindle version.


Can't blame you, it does look nicer.  

You could make your own that might have improved aesthetics?

Or you could turn your own backing plate.  I'm going to do that for my Grizzly G0752Z.  Couldn't buy a back plate that would fit an ER40 tru set chuck.  None available for the next 5 months.  I scoured the internet, with no luck.  Bought a chunk of cast iron and will make my own.  Iron arriving tomorrow.


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## RandyWilson (Jan 26, 2022)

And yes, like all great "mis-heard lyrics", they will forever be known as Minila The's, thanks to ToT.


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> Just looked at the docs on the lathe, no mention of spindle taper!
> 
> My mini-lathe is from Little Machine Shop and made by Sieg (for LMS).  It has a MT3 taper in the spindle and a 20mm spindle bore.  I'd check the spindle for evidence of a taper.


Whoa!! I just checked... it's tapered! Mind blown... I had no idea. Looks like an MT3. This opens up the possibility of something like this:


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## DavidR8 (Jan 26, 2022)

I think I've lost the plot... what style and size of chuck do you want to mount?

Do you have something with an MT3 taper to see if it fits?


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## RandyWilson (Jan 26, 2022)

How about a compromise? An MT3 - 1" 8tpi adapter to your mandrel?



			Amazon.com


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## rwm (Jan 26, 2022)

RandyWilson said:


> How about a compromise? An MT3 - 1" 8tpi adapter to your mandrel?
> 
> 
> 
> Amazon.com


That is a live center? That won't drive anything? Did I miss the point here?
I am not familiar with your lathe, but wouldn't it be fairly easy to machine this adapter?
R


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## bcrimmins (Jan 26, 2022)

DavidR8 said:


> I think I've lost the plot... what style and size of chuck do you want to mount?
> 
> Do you have something with an MT3 taper to see if it fits?


Looking to mount this:


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## bcrimmins (Jan 26, 2022)

rwm said:


> That is a live center? That won't drive anything? Did I miss the point here?
> I am not familiar with your lathe, but wouldn't it be fairly easy to machine this adapter?
> R


Yeah, that's live center. I would not want a live center.


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## RandyWilson (Jan 26, 2022)

Yep, that link was for a live one, first thing I found and I was being called to the dinner table. There should be a dead one out there. If not, it would be easier to make one than to adapt to the chuck flange.


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## bcrimmins (Jan 26, 2022)

I hate the idea of building a chimera... but I suppose this is an option....



			https://www.mscdirect.com/product/details/92301662


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## bcrimmins (Jan 26, 2022)

RandyWilson said:


> Yep, that link was for a live one, first thing I found and I was being called to the dinner table. There should be a dead one out there. If not, it would be easier to make one than to adapt to the chuck flange.


I'm too new to lathe-ing to trust myself to get the precision right. I see the wobble already.


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## DavidR8 (Jan 26, 2022)

bcrimmins said:


> Looking to mount this:
> 
> View attachment 393866


Do you have a link for that?


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## bcrimmins (Jan 26, 2022)

Grizzley has the right idea... but looks like they only make an MT2 version. 









						Chuck Reversing Adapter 1"-8 Pitch Chuck to #2 Morse Taper at Grizzly.com
					

Allows easy transfer centering projects from standard chucks to a vacuum head by attaching a standard chuck on to a tail stock with a one-way type live center or #2 Morse taper. 1"x8 chuck to #2 Morse taper.




					www.grizzly.com


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## bcrimmins (Jan 26, 2022)

DavidR8 said:


> Do you have a link for that?







__





						Artisan Ring Turning Chuck | Projects | Craft Supplies USA
					

Shopping for Turning Tools, like Artisan Ring Turning Chuck is easy at Craft Supplies USA.  Not only do we offer Turning Tools, we also have a full range of related items for woodturners at exceptional prices.




					www.woodturnerscatalog.com


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## RandyWilson (Jan 26, 2022)

MT2 to MT3 adapters are cheap. I was trying to avoid that for simplicity.


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## Firebrick43 (Jan 26, 2022)

The make blank arbors that are machineable.  So you could make exactly what you want.  If you get the drawbar style its retained by a threaded rod thru the spindle.


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## DavidR8 (Jan 26, 2022)

This might work with a MT3-->MT2 adapter.
A person could saw off the tang and drill and tap it for a drawbar made of threaded rod.








						Hold Fast Chuck Reversing Adapter
					

Accurately positioning a bowl on your vacuum chuck is quick and easy with the TMI™ Hold Fast Reverse Chucking Alignment Adapter. Just thread the adapter into the chuck or faceplate that's attached to the workpiece, mount the adapter in your tailstock and slide the tailstock forward to position...



					buffalowoodturningproducts.com


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## ErichKeane (Jan 26, 2022)

Firebrick43 said:


> The make blank arbors that are machineable.  So you could make exactly what you want.  If you get the drawbar style its retained by a threaded rod thru the spindle.
> 
> 
> mt3 machineable blank


The blank might not work, he doesn't have 8 tpi on that lathe for single pointing   Though perhaps someone could make it for him.


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## Firebrick43 (Jan 26, 2022)

ErichKeane said:


> The blank might not work, he doesn't have 8 tpi on that lathe for single pointing   Though perhaps someone could make it for him.


No, i mean machine the ring holder right on the machinable mandrel.  Why do people want to always put and adapter, on an adapter, on an adapter.

Just taper the nose, drill the end, tap to the size of the inner hole of your taper cones, and locktite the appropriate size stud in the tapped hole.


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## rwm (Jan 26, 2022)

Can't turn an 8 TPI thread?


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## RandyWilson (Jan 26, 2022)

BTW, I see no where that the spindle diameter is mentioned for that ring mandrel. I took a guess at 1" - 8 since it's a common woodworking size, but that might not be correct.


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## bcrimmins (Jan 26, 2022)

ErichKeane said:


> The blank might not work, he doesn't have 8 tpi on that lathe for single pointing   Though perhaps someone could make it for him.


Actually, I found an old app that calculates the the gear specs to cut 8 TPI threads on a HF mini.


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## WobblyHand (Jan 26, 2022)

According to LMS, the gearing for a 7x10 mini-lathe to get 8 TPI threads is A=40, B=any, C=any, D=20, with a 16 TPI lead screw.  According to HF, he should have both 40 and 20 tooth gears.


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## bcrimmins (Jan 26, 2022)

RandyWilson said:


> BTW, I see no where that the spindle diameter is mentioned for that ring mandrel. I took a guess at 1" - 8 since it's a common woodworking size, but that might not be correct.


I comes in both sizes:


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## Shootymacshootface (Jan 26, 2022)

rwm said:


> Can't turn an 8 TPI thread?


That's what I was thinking.


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## WobblyHand (Jan 26, 2022)

Here's the Little Machine Shop Gear calculator.
Mini-lathe gear calculator


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## rwm (Jan 26, 2022)

Assuming you can turn the 8 TPI it would be a fun project to make an adapter from an MT3 blank.
Use the draw bar style so the chuck can't fly off.


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## WobblyHand (Jan 26, 2022)

LMS has a blank arbor that might be suitable.  Seems to be backordered, but the date expected is Jan 31,2022.
MT3 blank arbor  Price is very good.  Would be a great project.  Is even drilled and tapped for a drawbar.  Even if one messed up, the raw stock is pretty inexpensive.


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> LMS has a blank arbor that might be suitable.  Seems to be backordered, but the date expected is Jan 31,2022.
> MT3 blank arbor  Price is very good.  Would be a great project.  Is even drilled and tapped for a drawbar.  Even if one messed up, the raw stock is pretty inexpensive.


That would be a fun project. The blank part looks kinda short. Not sure a ring, a tapered bushing and a nut would fit very comfortably. I'll look for a long blank.


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## bcrimmins (Jan 26, 2022)

This blank has a 30mm machining end. 






						Shank MT3 Morse Taper Soft Blank End Arbor -Lathe Mill Drill Teng Type 25 x 30mm - - Amazon.com
					

Shank MT3 Morse Taper Soft Blank End Arbor -Lathe Mill Drill Teng Type 25 x 30mm - - Amazon.com



					www.amazon.com


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> That would be a fun project. The blank part looks kinda short. Not sure a ring, a tapered bushing and a nut would fit very comfortably. I'll look for a long blank.


The slug at the end is 1.5" diameter, perfect for making a 1" screw.  Use a 1/4" flange, and have 1-1/4" long screw.  Roughly 8 threads, which is twice as many threads as needed.  The taper will seat roughly flush.


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> This blank has a 30mm machining end.
> 
> 
> 
> ...


But it is only 25mm in diameter.  Besides, you don't need a nut!  Just screw in until the flange hits the mandrel.  That way the mandrel will be straight.


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## bcrimmins (Jan 26, 2022)

WobblyHand said:


> The slug at the end is 1.5" diameter, perfect for making a 1" screw.  Use a 1/4" flange, and have 1-1/4" long screw.  Roughly 8 threads, which is twice as many threads as needed.  The taper will seat roughly flush.


Yes, I could do that. I might. But I was actually thinking that I would machine a ring mandrel directly into the blank, as @WobblyHand suggested.


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## WobblyHand (Jan 26, 2022)

WobblyHand said:


> But it is only 25mm in diameter.  Besides, you don't need a nut!  Just screw in until the flange hits the mandrel.  That way the mandrel will be straight.


And 1.5 inches is over 37mm, so you have a little breathing room.  Remember, you can always machine it off, but it's hard to put back!


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## Aaron_W (Jan 26, 2022)

You could also just put a 1"-8 thread on the end of a short rod, and stuff it in a 4 jaw chuck, or 3 jaw if a little run out is acceptable.


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## WobblyHand (Jan 26, 2022)

bcrimmins said:


> Yes, I could do that. I might. But I was actually thinking that I would machine a ring mandrel directly into the blank, as @WobblyHand suggested.


He's a smart cookie.


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## bcrimmins (Jan 26, 2022)

The project:


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## rwm (Jan 27, 2022)

Is it OK that the cones will hide the edges of the ring? Should you consider an expanding mandrel type setup?


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## Alcap (Jan 27, 2022)

I’m curious , will there be any issues putting side load on a tang arbor in the lathe ? In case I ever need to do a similar job .


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## DavidR8 (Jan 27, 2022)

@Alcap Were it me I'd cut the tang off, drill and tap the end for 1/4-20 or maybe 3/8-16 (if there's sufficient material) so that a drawbar of threaded rod could be used.


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## bcrimmins (Jan 27, 2022)

DavidR8 said:


> @Alcap Were it me I'd cut the tang off, drill and tap the end for 1/4-20 or maybe 3/8-16 (if there's sufficient material) so that a drawbar of threaded rod could be used.


That's a good thought. 


rwm said:


> Is it OK that the cones will hide the edges of the ring? Should you consider an expanding mandrel type setup?


You don't want the 'cones' to be too high. But it depends on whether you're using ring blanks or if your cutting them entirely out of raw material. That said, ring mandrels of this kind I car about (mostly using ring blanks) usually come with multiple sets of 'cones' for different size rings. 

Expanding mandrels are great too. I made a wooden one but it was wonky. The metal ones are often sold in sets in order to cover all the ring sizes and so they can get quite expensive. Like this:










IMHO, this is the most-brilliant design of all of them. $125.


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## rwm (Jan 27, 2022)

That is beautiful and clever! I have made simple expanding ring mandrels to cover the common sizes I use and then I just chuck it in a 4 jaw and dial it in.




Flat head screw expands it just fine. I made the cut on a bandsaw. Simple.


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## WobblyHand (Jan 27, 2022)

DavidR8 said:


> @Alcap Were it me I'd cut the tang off, drill and tap the end for 1/4-20 or maybe 3/8-16 (if there's sufficient material) so that a drawbar of threaded rod could be used.







That was the LMS link that I provided.  Comes drilled and tapped for 3/8-16,  $12.95.  Fat end is 1.5" diameter, 1.5" long.  MT3.  I'll probably order one, just because.  Seems like a handy thing to have.  Could probably turn it to size, slit it, thread it, and make a tapered pin to expand it.  A short version of the Breakheart tool.


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## bcrimmins (Jan 27, 2022)

WobblyHand said:


> View attachment 394009
> 
> That was the LMS link that I provided.  Comes drilled and tapped for 3/8-16,  $12.95.  Fat end is 1.5" diameter, 1.5" long.  MT3.  I'll probably order one, just because.  Seems like a handy thing to have.  Could probably turn it to size, slit it, thread it, and make a tapered pin to expand it.  A short version of the Breakheart tool.


I agree... worth having around. I just order this one on amazon. https://www.amazon.com/dp/B06WRVKWYP/


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## homebrewed (Jan 28, 2022)

The "expanding" mandrel with the matching tapered fingers is a pretty cool solution.  If the commercial version is too expensive, I don't think it would be too difficult to make one (depending on what other machine tools you've got).  I wouldn't think it would require a lot of accuracy to shape this kind of jewelry so a DIY version should be feasible.  Don't over-engineer it if it's not required


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## Firebrick43 (Jan 28, 2022)

bcrimmins said:


> That's a good thought.
> 
> You don't want the 'cones' to be too high. But it depends on whether you're using ring blanks or if your cutting them entirely out of raw material. That said, ring mandrels of this kind I car about (mostly using ring blanks) usually come with multiple sets of 'cones' for different size rings.
> 
> ...


to bad they have such a nice looking product and have such crappy knurling on the thumb screw


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## bcrimmins (Feb 6, 2022)

I'm sad. I drilled out the shank and tapped at 5/16 - 24. Used my CO2 laser to cut an acrylic version of the awesome ring mandrel. Spun it up... and IT WOBBLES!!! The hole is offset by about 2/100's of an inch. I think what happened was that the face of the shank has a pilot dimple and I trusted that to be the guide for the point of the drill. In retrospect, I think I should have shaved the face flat and then drilled my own pilot hole with, say, a 1/8 bit. But I'm a lathe newby so I'm grateful for any wisdom y'all want to throw my way. 

And, of course, I now have a shank with a tapped 5/16 hole in the wrong spot. I don't think I can re-drill it because the existing hole will drag the new drill off center. Although maybe an end mill bit moved in slowly would keep true? This also presents the opportunity (read, 'excuse') to experiment/learn with a boring head. Am I right that this would be a use case for a bore?

I could also just buy a new shank... which is way cheaper than a boring head. And besides, the ring mandrel I've designed kinda needs a 5/16 rod to be effective -- if it's any bigger, then the 'jaws' will need to be thinner or else small ring sizes won't work because I'd have to the diameter of the jaws to account for the relative weakness of the acrylic. 

I probably should just have shelled out the dough for one of the awesome mandrels... .but trying to fabricate one is a fun opportunity to learn to ue my new mini lathe.


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## Firebrick43 (Feb 6, 2022)

Probably not the drill but the tap.  You will always get wobble like this.  Drill and ream a hole (next stock size up) in your soft shank.  Use green locktite to retain the new piece of stock(say 3/8 if your doing 5/16 threads).  After it sets up for 24 hours cut the glued in shank down to 5/16.  Cut threads single point but not under where the ring sets.   Just like the unimandrel above.  Even better, don't cut any threads under any part of the mandrel at max extension(smallest size ring you will do) and use spacers under the nut for bigger rings


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## Alcap (Feb 6, 2022)

How deep did you drill the hole ? Could you just face off threads ?


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## rwm (Feb 6, 2022)

.020" is pretty bad. To get a hole dead center, it should be drilled undersized and finished with a boring bar. You would need one of those tiny boring bars for a hole this small.
You could start over with a new shank or loctite a plug in place as suggested above. Either way you should use a boring bar to center the new hole.
Keep this in mind:
Drilling is for making a rough hole.
Boring is for making a hole on center.
Reaming is for making a hole to exact diameter.
Sometimes you need to do all 3.


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## bcrimmins (Feb 6, 2022)

Firebrick43 said:


> Probably not the drill but the tap.  You will always get wobble like this.  Drill and ream a hole (next stock size up) in your soft shank.  Use green locktite to retain the new piece of stock(say 3/8 if your doing 5/16 threads).  After it sets up for 24 hours cut the glued in shank down to 5/16.  Cut threads single point but not under where the ring sets.   Just like the unimandrel above.  Even better, don't cut any threads under any part of the mandrel at max extension(smallest size ring you will do) and use spacers under the nut for bigger rings


Ah, good to learn. Makes perfect sense. Two questions...

What did you mean by "single point"?

Any tips on cutting threads? I've never done that. I've watched some youtube videos.


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## Firebrick43 (Feb 6, 2022)

single point is to cut threads with a single point 60 degree tool bit.  

As far as tips, go as slow as you can, take small passes, and use a good cutting oil.


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## rwm (Feb 6, 2022)

Single pointing the threads would eliminate the need for boring. You will still need a very small internal threading tool. I think boring and tapping would be fine. Single point is arguably harder but would guarantee concentricity.
R


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## bcrimmins (Feb 6, 2022)

Alcap said:


> How deep did you drill the hole ? Could you just face off threads ?


All the way to the base shank. Ironically, I drilled it all the way in because I knew there would be some play in the threads and wanted it to wicked less. That was clearly the wrong thing to focus on!


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## bcrimmins (Feb 6, 2022)

rwm said:


> .020" is pretty bad. To get a hole dead center, it should be drilled undersized and finished with a boring bar. You would need one of those tiny boring bars for a hole this small.
> You could start over with a new shank or loctite a plug in place as suggested above. Either way you should use a boring bar to center the new hole.
> Keep this in mind:
> Drilling is for making a rough hole.
> ...


Great info, thanks!


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## Firebrick43 (Feb 6, 2022)

rwm said:


> Single pointing the threads would eliminate the need for boring. You will still need a very small internal threading tool. I think boring and tapping would be fine. Single point is arguably harder but would guarantee concentricity.
> R


Don't single point internal threads????  Locktite a 3/8 shaft into a 3/8 hole , turn to 5/16 diameter and single point the external threads on the end for a thumb screw.


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## bcrimmins (Feb 6, 2022)

Firebrick43 said:


> Don't single point internal threads????  Locktite a 3/8 shaft into a 3/8 hole , turn to 5/16 diameter and single point the external threads on the end for a thumb screw.


Yeah, that's what I thought you meant. I like it.


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## Firebrick43 (Feb 6, 2022)

bcrimmins said:


> Yeah, that's what I thought you meant. I like it.


Also if you mess up, or want to change things in the future, green locktite while "permanent" if heated to 400 degrees will let go so you can have a do over.


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## bcrimmins (Feb 6, 2022)

What shape tool would you use the reduce the 3/8 stock down to 5/16?


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## Firebrick43 (Feb 6, 2022)

Any good right hand tool/holder that has a sharp cutting edge and has positive geometry would work.  HSS would have the lowest pressure and therefore limit deflection of the shaft. 

I personally would use a tangential tool holder but that is because I have one.  A CCMT 21.52 RH tool holder (SCLCR)  would work as well. 

While I still don't know why they do it, a RH tool is meant to cut to the Left towards the chuck.

I personally don't care for triangle inserts most of the time.  

I would use HSS for threading but you would need to learn to grind it.  I also have a number 1 top notch tool that takes threading inserts that works well but probably more expensive than many want.  Laydown threading tool holders seem to be much more reasonably priced but I have not really used them.


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## rwm (Feb 6, 2022)

Sorry guys! I completely misunderstood what Firebrick was proposing. Yes- that is a good solution.


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## bcrimmins (Feb 6, 2022)

See


Firebrick43 said:


> Any good right hand tool/holder that has a sharp cutting edge and has positive geometry would work.  HSS would have the lowest pressure and therefore limit deflection of the shaft.
> 
> I personally would use a tangential tool holder but that is because I have one.  A CCMT 21.52 RH tool holder (SCLCR)  would work as well.
> 
> ...


So what I'm hearing is the the stock index cutters that come with the HF mini lathe are not the right call.  

I can be a maniac about acquiring tools that I use once and then end up in a bin. What would your recommendation be for a tool set that would be versatile and reasonably economical?


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## bcrimmins (Feb 6, 2022)

For example, are these crap?



			https://www.amazon.com/dp/B083JWGSYZ


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## ttabbal (Feb 6, 2022)

bcrimmins said:


> For example, are these crap?
> 
> 
> 
> https://www.amazon.com/dp/B083JWGSYZ



They aren't great, but they aren't crap. What you run into is that the inserts tend to be molded and not very sharp. That increases tool pressure and deflection of the part. On a mini lathe those can be very important. 

You can get honed/polished inserts. They are generally intended for aluminum, but will cut steels nicely. They won't last as long, but will work better, particularly for a small machine. 

Grinding HSS is probably the best option for a mini. Get it really sharp and you can get very good cutting with it.


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## bcrimmins (Feb 6, 2022)

ttabbal said:


> They aren't great, but they aren't crap. What you run into is that the inserts tend to be molded and not very sharp. That increases tool pressure and deflection of the part. On a mini lathe those can be very important.
> 
> You can get honed/polished inserts. They are generally intended for aluminum, but will cut steels nicely. They won't last as long, but will work better, particularly for a small machine.
> 
> Grinding HSS is probably the best option for a mini. Get it really sharp and you can get very good cutting with it.


Oh, so hhs cuts better ( e.g., less pressure) than carbide?

How difficult is it to get good at sharpening hhs cutters?


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## DavidR8 (Feb 6, 2022)

bcrimmins said:


> Oh, so hhs cuts better ( e.g., less pressure) than carbide?
> 
> How difficult is it to get good at sharpening hhs cutters?


Have a look in the Beginners section for @mikey's excellent treatise on grinding HSS tools.


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## ttabbal (Feb 6, 2022)

bcrimmins said:


> Oh, so hhs cuts better ( e.g., less pressure) than carbide?
> 
> How difficult is it to get good at sharpening hhs cutters?



Yes. Mostly due to the sharpness you can achieve. Carbide is brittle, so a really fine edge can be fragile. HSS has a bit more give. 

Grinding and sharpening looks harder than it is. It just takes a little practice to get the feel for it. 

The thread mentioned above is what I call the Book of @mikey. It's well worth reading. And with a mini lathe, the bits are smaller and faster to grind.


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## ErichKeane (Feb 6, 2022)

bcrimmins said:


> Oh, so hhs cuts better ( e.g., less pressure) than carbide?
> 
> How difficult is it to get good at sharpening hhs cutters?


One thing I learned is you don't have to be all that good at grinding cutters to be better than carbide on a lathe. I did pretty well just eyeballing angles and not really going for a particular angle (just watched the ToT video), and did better than the import carbide.

What helped the most was some sort of stone to get a fine hone.


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## bcrimmins (Feb 6, 2022)

Could someone share a link to Mikey's hhs grinding post. He's been a prolific poster and I'm not sure I have found the referenced post. Thanks!


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## DavidR8 (Feb 6, 2022)

Models for grinding HSS Lathe Tools
					

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/threads/lathe-accessories-tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing...




					www.hobby-machinist.com


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## Firebrick43 (Feb 6, 2022)

bcrimmins said:


> For example, are these crap?
> 
> 
> 
> https://www.amazon.com/dp/B083JWGSYZ


No, the holders are not.  As others have said, there are different grades/geometery of inserts that give a better surface finish on light weight lathes such as yours.  

You can even get HSS inserts for those tool holders.  

warner hss insert


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## bcrimmins (Feb 6, 2022)

for the HF mini, is it necessary to use 1/4" holders? Or can I get away with 3/8"? What are the implications of that extra 1/8" of height causing a different contact angle/position?


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## ttabbal (Feb 6, 2022)

bcrimmins said:


> for the HF mini, is it necessary to use 1/4" holders? Or can I get away with 3/8"? What are the implications of that extra 1/8" of height causing a different contact angle/position?



It can make it difficult to get the cutting edge on center. HSS can just be ground differently to make up for it.


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## bcrimmins (Feb 6, 2022)

ttabbal said:


> It can make it difficult to get the cutting edge on center. HSS can just be ground differently to make up for it.


Good point, RE grinding down the HHS


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## bcrimmins (Feb 6, 2022)

Just want to say... WOW... thank you all so much for the masterclass!! Just what I needed to get my lathe journey started!


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## homebrewed (Feb 7, 2022)

1/4" sized HSS blanks won't take as long to grind to shape compared to 3/8" ones.  They won't be quite as strong as 3/8" cutters but I don't think an un-modified mini lathe has enough power to break one, unless you crash the tool into a rapidly spinning chuck.  I've used both sizes with no mishap.

The 4 way toolholder that comes with these machines is designed for 5/16" sized cutters so that is something to consider.  To use 1/4" cutters in it you will need either a spacer under the toolholder to elevate it, or spacers underneath the individual cutters.  A QCTP makes it a lot easier to swap in different-sized cutters and get them on-center.


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## bcrimmins (Feb 18, 2022)

UPDATE

Hey gang, been traveling and slammed, but managed to actually fabricate a functional ring chuck out acrylic on my laser cutter. Made my first ring ever on it and it worked great! But I can tell it's pretty fragile and so I'd only get two or three rigns out of it before having to make a new one. Which is easy. But I'm going to redesign it to be more robust... maybe get 10 rings out of one.  

Thanks again for all of the advice!!


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## rwm (Feb 18, 2022)

That is awesome! Nice work. What is your plan to upgrade this?


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## bcrimmins (Feb 18, 2022)

rwm said:


> That is awesome! Nice work. What is your plan to upgrade this?



Double the base thickness so that the 'fins' can be inserted deeper for a stronger hold. 
Increase the thickness of the fins from 3mm to 4 or 5mm, for strength and stability.
Increase the over all length by about an inch to reduce the angle of the fins. This will increase the contact surface area between the ring and the fins and lessen the tendency of the ring edge to mar the fins' edges.


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