Machining tools for a micro lathe.

[Owen_N]

Where do I get these from? everything online seems to be too big. I have a toolpost that can take up to 10mm tall tool holders.

I want 1.5mm thick parting-off tools and tools for making ring grooves, and holders that will fit and bring the edge to the right height. This is about 2mm up from the centre of the holder.
I also need boring bars starting around 10mm bore , up to 35mm. I have a bar with 1/8 square HSS stock tips, but the grubscrew holders are no good. Even with grade 10.1 grubscrews, they would be
not than useful.
Also, for two stroke ring pins, what material should I use? they look about 0.5mm.
What drill do I need and how much interference fit? what kind of pushing tool should I use?

 

[darwenguy]

I use the generic chineese tools from ebay, i use mostly the 10mm insert holders, they work fine with 'decent' inserts. A full set can be got for around £20. HSS tool steel is readily available also.
Search for mini lathe tools and you will find plenty.

Luke.

 

[Jasonb]

You can always ditch the toolpost and clamp directly to teh top of teh slide with suitable packing then you could look for the "Minithin" by Nikcole, they do a 8mm" shank holder and a range of different inserts - parting, grooving, threading, round ended, etc. I use mine for piston tings, E clips grooves etc

http://niko-nikcole.com/nikcole-mini-systems-2/

 

[Steamchick]

You asked: "for two stroke ring pins, what material should I use? they look about 0.5mm. ".
I have never done this (pistons I bought were proprietary items pre-fitted with ring pins), but "when a lad in the 1960s" was taught that ring pins for motorcycle engines of a vintage 1940s~1960s would be brass or copper. There is really very little shear force on ring pins, they simple prevent rotation of rings (as I'm sure you know?).
K2

 

[timo_gross]

Where do I get these from? everything online seems to be too big. I have a toolpost that can take up to 10mm tall tool holders.

I want 1.5mm thick parting-off tools and tools for making ring grooves, and holders that will fit and bring the edge to the right height. This is about 2mm up from the centre of the holder.
I also need boring bars starting around 10mm bore , up to 35mm. I have a bar with 1/8 square HSS stock tips, but the grubscrew holders are no good. Even with grade 10.1 grubscrews, they would be
not than useful.
Also, for two stroke ring pins, what material should I use? they look about 0.5mm.
What drill do I need and how much interference fit? what kind of pushing tool should I use?

I am not entirely sure if my comment matches your question.

You could make small groove tools from HSS? You start with a drillblank. (grind half of it off and put a front relief on. If you cannot buy HSS drill blanks, just sacrifice a drill? ) That way you do not have to worry too much about the width and you do not have to grind much. (should be doable even free hand.
Then you just have to make some square block with a 1.5mm hole to accomodate the drill blank, in the sketch I put the round HSS at an angle, that would make automatic top rake and fine height adjustment. A set screw perpendicular holds it in place.
Or you just glue it in place I guess that also can work.

Worked and not! With Brass it works really nice. In Steel I broke it off right away, very delicate the thin round half tool.
So the fotos show the 2nd approach. If cutting is really really careful it still seems to work.
The stock on foto is 20 mm diameter cold rolled steel; the groove tool is 1.9 mm wide. (was the smallest HSS blank I had in my toolbox)
I clamped the mild steel block into the toolpost. 1.9 mm drill into the chuck. Then drilled by moving the toolpost in.
Drilled and Tapped M3 from the side also using the lathe spindle as drill.
Tool has no top rake, the front relief I ground free hand with belt sander.

Greetings Timo

 

[timo_gross]

Just noticed it can also do face grooves.

The tool is ideal for interrupted cutting.

• You cut a little
  
• The tool breaks
  
• You fiddle the tool out of the fixture
  
• Grind a new tip
  
• Continue cutting.

Good points the side relief is sufficient for all sorts of face grooves without rubbing. The grinding is rel. easy.


Greetings Timo

 

[Steamchick]

Brilliant Timo! I now have another use for broken taps, drills and tool bits (always have a good stock of these materials in various sizes, just never the right size!).
K2

 

[pete]

While I don't know it for sure, I suspect tap shanks may be just like the shanks of drills. What many don't seem to know is there purposely left much softer than the actual part of the tool that's expected to do the work. It's for a good logical reason since it allows the tightened drill chuck jaws to slightly deform the drill shank within it's elastic range to obtain a better grip and prevent spinning within the chuck jaws. And since there's no real need for tap shanks to be fully hardened and a few good one's why they wouldn't be, it's logical there not either. So even a HSS drill and probably those taps will not have the correct hardness to make a proper cutting tool from it's plain shank. And for most of us, even trying to heat treat that softer portion of a HSS tool shank in a home shop is just about impossible. There's a vast difference with far higher temperatures and much more critical time periods between how HSS and high carbon steels get heat treated. High carbon is quite easy in comparison. Fortunately it's not really necessary to even try since fully hardened round or square tool blanks are readily available for more than reasonable prices from any larger tool suppliers. Or there's still lots of good brand name NOS on places like Ebay. For the costs of even a couple of good replaceable tip tool shanks and the tips, you could buy almost a lifetimes supply of HSS. And the smaller the lathe the more logical it is to use cutting tools honed to razor sharpness such as HSS because of the lathes lack of HP and rigidity. Learning to grind HSS to the correct angles for the material your cutting simply isn't optional if you own a lathe. Carbide tipped tools can be helpful sometimes depending on the material and the condition it's in that your cutting, but in a home shop far too many forget it's generally a much more expensive convenience than a real requirement.

 

[Steamchick]

Thanks Pete.
Good advice. NEW HSS is best!
I have been grinding my own tools for half a life-time, and so far seem to be having reasonable success - and use a lot of HSS as well as new and re-sharpened carbide bits - some brazed onto mild-steel holders to make my own tipped-tools. 2 proprietary tools and 3 of mine here. Spot the home-made tools!

I particularly like this "Diamond" tool holder - I made a copy and jig for sharpening the HSS bits: It doesn't use a diamond, but I think is based on one that does?

It cleverly uses geometry to take a simple angle ground onto the tool bit to give all the clearances etc. for a good tool - easy to re-sharpen correctly with the jig. It is also adjustable to get an exact centre height. - But it needs a chip-breaking groove to be ground carefully just behind the cutting point.
But (Sorry!) none of this diatribe helps Owen N.
I did find this on't web:
http://www.carbidecuttinginserts.co...s-mgmn150-g-thin-and-narrow-cutting-edge.htmlhttp://news.thomasnet.com/fullstory/Carbide-Inserts-come-in-narrow-groove-widths-491036KENNAMETAL Carbide Grooving Insert V10G252R059 KC5035 (5 Pack) - Dan's Discount Tools (dansdiscounttools.com)
ABSF MGEHR1010-1.5 10x10x100mm External Grooving Lathe Cutting Boring Bar Tool Holder – Grandado

Just a matter of searching, searching...? It is probably out there,... somewhere!

K2

 

[timo_gross]

While I don't know it for sure, I suspect tap shanks may be just like the shanks of drills. What many don't seem to know is there purposely left much softer than the actual part of the tool that's expected to do the work. It's for a good logical reason since it allows the tightened drill chuck jaws to slightly deform the drill shank within it's elastic range to obtain a better grip and prevent spinning within the chuck jaws. And since there's no real need for tap shanks to be fully hardened and a few good one's why they wouldn't be, it's logical there not either. So even a HSS drill and probably those taps will not have the correct hardness to make a proper cutting tool from it's plain shank. And for most of us, even trying to heat treat that softer portion of a HSS tool shank in a home shop is just about impossible. There's a vast difference with far higher temperatures and much more critical time periods between how HSS and high carbon steels get heat treated. High carbon is quite easy in comparison. Fortunately it's not really necessary to even try since fully hardened round or square tool blanks are readily available for more than reasonable prices from any larger tool suppliers. Or there's still lots of good brand name NOS on places like Ebay. For the costs of even a couple of good replaceable tip tool shanks and the tips, you could buy almost a lifetimes supply of HSS. And the smaller the lathe the more logical it is to use cutting tools honed to razor sharpness such as HSS because of the lathes lack of HP and rigidity. Learning to grind HSS to the correct angles for the material your cutting simply isn't optional if you own a lathe. Carbide tipped tools can be helpful sometimes depending on the material and the condition it's in that your cutting, but in a home shop far too many forget it's generally a much more expensive convenience than a real requirement.

I think that all depends.

Nothing to worry, as long as it works I would not care. If the drill shank or broken tap is harder than the workpiece it is good enough to become a potential tool for the hobby shop.

The smaller HSS drills, work or break. They never bend. The shank portion also breaks brittle no bending or sign that they have a soft(er?) shank. (I do not have scientific proof for this ). Bigger drills somethimes get marks from the chuck when they happen to spin. ( makes me think you have a point )
I guess this all varies from size to manufacturer to type/model and actual material. There are so many ways to do things. ( new methods come, old methods stay ) What was production method 10 years ago is not necessary still the way everybody does things today.

Prehardened HSS pins ready to grind start from 1 mm and come in 0.1 mm increments, were I buy tools. They cost around the same as a drill in similar size or a little less ( same brand) Good thing: the shop sells everything single, so I do not need to buy bulk.

The question is if the tools are ground from a full blank after hardening? Or made in any other way.
for example small carbide endmills are definitely ground from one solid blank and can be repurposed.

Greetings Timo

p.s. the experiment from yesterday was done with a HSS blank, not a repurposed tool.

 

[Steamchick]

I like the mini-thins.
K2

 

[timo_gross]

....But (Sorry!) none of this diatribe helps Owen N. ....

K2

I had to ask google, because I am only learing my English as I go along:

diatribe
/ˈdʌɪətrʌɪb/
noun
noun: diatribe; plural noun: diatribes

1. a forceful and bitter verbal attack against someone or something.
   "a diatribe against consumerism"

I hope there was nothing that came across like a verbal attack from my side yet .
I think so far this thread might help because it points to alternative directions.

I use the grooving inserts less and less, because:

• need a separate holder for every width
• something goes wrong during parting, there is a chance the holder gets damaged
• the inserts are expensive.
• Results with HSS are not considerably inferior to the insert.

The grooving tool holder from your link is 12 mm square, Owen is searching for something smaller than 10 mm. And to bring it to center height he might have to cut it even more. I would just get the too big one and mill the unwanted material off. Entry level holders can be milled with a proper carbide endmill no problem.

Greetings Timo

p.s. I guess Owen has already produced all the pistons without our "help" (someone I know still did not start making the water glas for his model boiler)

 

[Steamchick]

Hi Timo, you are a Gentleman and have not caused any offence.
Sorry, it was my error.
I didn't check the true meaning of "diatribe"! Call me "a stupid Englishman" for not understanding my own language. I used it to mean that I was doing the Politicians' thing of answering the question I wanted, but was not the question that was asked. I do go off topic.... because I am "a stupid Englishman"...
End of my apology.
K2

 

[abby]

I re-purpose broken HSS slitting saws into parting off tools. They can be cut into strips with a cutting disc in an angle grinder.
I made a holder which fits in a rear toolpost , perfect for parting brass with minimum waste , and can be used for piston ring grooves etc.
Dan.

 

[timo_gross]

Hi Timo, you are a Gentleman and have not caused any offence.
Sorry, it was my error.
I didn't check the true meaning of "diatribe"! Call me "a stupid Englishman" for not understanding my own language. I used it to mean that I was doing the Politicians' thing of answering the question I wanted, but was not the question that was asked. I do go off topic.... because I am "a stupid Englishman"...
End of my apology.
K2

Maybe Google is just wrong, happens a lot, do not trust the bigdata more far than you can throw your Bridgeport mill.
We seem to just have hijacked the thread and learn something new about parting and grooving.

I re-purpose broken HSS slitting saws into parting off tools. They can be cut into strips with a cutting disc in an angle grinder.
I made a holder which fits in a rear toolpost , perfect for parting brass with minimum waste , and can be used for piston ring grooves etc.
Dan.

How do you secure the blade strips? I am curious to see a picture of your holder.

 

[Steamchick]

I have ground a piece of broken hacksaw blade to use as a thin grooving tool. It worked, sort of, as I was only making some grooves in a piston to act as a labyrinth seal. The saw set was a problem for any depth of cut. Trying to use the first tooth, the "Body" metal was not in alignment. So Dan, your slitting tool is a better idea.
Thanks!
K2

 

[stanstocker]

Greetings,

Hobby knife blades make excellent very thin part off or grooving tools. Before getting a rear tool post and AR Warner cut off tool set up this is what I used for parting brass bushings made for clock repair. Grind to a more useful shape, knock off the cutting edge so you don't slice yourself open while mounting the tool.

You do need minimal over hang with these, they are fragile like any tool would be in such a thin section.

Cheers,
Stan

 

[minh-thanh]

Maybe make tools like this video :