Need help with making lathe tools

[Dirty_Vinylpusher]

Hey guys, I recently bought a mini lathe and am thinking of making my own boring tools/
I had a look around the net and found a couple of sites with some info.
One was the Sherline site (http://www.sherline.com/grinding.htm).
Pretty good info there but mainly about turning tools, not boring bars.


A couple of pics from different angles of the tip would be very helpful.
If there's already another thread on this topic, please throw me the link.
Had a quick look around the forum but didn't see one.



Cheers.

 

[Niels Abildgaard]

What size of holes and depth are in Your mind?
Try the IFANGER catalouge for ideas and Komet on the german e-bay for prices.
Life is really to short to grind boring tool from complete HSS.In my youth I made many from mild steel and a small piece of HSS silver soldered together.

 

[Tin Falcon]

DVP there are general a couple of approaches depending on size and material used.

there are lager bars that typically have a hole drilled at either end and one hole is sare to the bar the other is 45 then set screw holes are installed to hold the cutting tool.
small ones are different look in a tool catalog for tiny boring bars for shape, turn down a piece of drill rod on the lathe for rough shape. then rough grind the cutting end heat the cutting end cherry red then quench in used motor oil (Outside of shop)then finsh grind. I would not try to cut steel with this but good for brass ali. you can also just hand grind one from a hss bit. I will to dig up some pics for you later.
Try to keep the diameter of your material to length of tool ratio to under 5.
Tin

 

[Dirty_Vinylpusher]

Ok sorry I didn't give much info did I.
I have the C2 mini lathe and it takes 8mm tools.

I bought a piece of HSS "Tool steel" from an engineering shop today.
It's about 70mm long, 8mm square and has a slight angle at each end.
Similar to this:

You'll have to be patient with me as I'm just learning all the proper terms for this lathe business. ;D


I do have a set of cutting tips, the diamond shaped ones, and a holder/bar for them, but that's only for turning.
I'll probably end up getting the holder for internal stuff but for now I thought I'd have a go at making one myself.


As for depth/size of holes... well... probably not very deep, maybe 20 - 30mm.
Size.... not sure.
Depends on what I need to make.

Most of my stuff will be related to making parts for large scale radio controlled cars, like wheel hubs etc.
Anything up to 1/2 inch I'll just drill using a drillbit, but some larger stuff will require a boring bar/tool.
Max capacity of the chuck is 70mm so I might be making, say 60mm diameter holes at the most.


I'll mostly work with aluminium.



Cheers.

 

[winklmj]

Not boring bars but lathe tools in general. Lots of good info on relief and rake, etc... Watch his other vids too.

[ame]http://www.youtube.com/watch?v=hrDr4rYLiAk[/ame]

 

[Dirty_Vinylpusher]

That was a great video!
Love how he uses large pieces of timber to demonstrate.
I'll check out his other ones later.


Still no boring tool pics, guys?

 

[tel]

Hey DVP, take a look here - boring tool pics a'plenty!
http://www.google.com.au/images?client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hl=en&source=imghp&biw=&bih=&q=boring+tool&btnG=Search+Images&gbv=1

 

[Tin Falcon]

Make it look something like this

the end view of the business end will be more or less a half circle in profile if you make the end relief and side relief about the same angles as the top view you should be fine.
Hope this helps .
Photo is a link to the MSC site. it is actually a solid carbide boring bar. Keep in mind that the main thing with any cutter is clearance if the back edge rubs the part the tool can not cut. Also a bit of a radius put on with a hand stone will help your finish as a matter of fact stone the whole thing to polish up the edges.
Tin

 

[Dirty_Vinylpusher]

Yeah cheers, Tel.
That just confused me even more :big:


Seriously though, this picture helps a bit.

And thanks to Tin Falcon too.
We're getting closer.

 

[Dirty_Vinylpusher]

When you talk about end relief and side relief, you mean these angles or the ones we can't see in that picture.....?

 

[Tin Falcon]

I mean the ones yo can not see on the side of the tool and end of the tool.


An image from littlemachineshop.com

they call it side relief and front relief.

and here are the suggested angles.

http://littlemachineshop.com/Reference/RakeRelief.php
Tin

 

[Dirty_Vinylpusher]

Ok.

Here's the piece of tool steel I've got.
In the pictures I'm rolling it forward/away from me 1/4 turn at a time.
If I wanna make the left hand end the cutting end, which side should be the top?

SIDE 1

SIDE 2

SIDE 3

SIDE 4

(Ignore the dent in the piece here, that was just me checking how well the bench grinder would work on this steel.... stickpoke)

 

[Tin Falcon]

I would say make side one the top I would start by grinding the area away just below sutton tools.
Tin

 

[Dirty_Vinylpusher]

Thanks again.

I'll have a go and see what I come up with.

 

[Tin Falcon]

DVP:
I found the photo of my home/ made ones

the top one was ground from HSS the bottom one made from drill rod aka silver steel
it was turned on the lathe then ground heat treated and finish ground hope this helps good luck with yours.
Tin

 

[arnoldb]

Hi DVP

Here's how I made one of my favourite little boring bars from a "busted up" drill rod (silver steel) connecting rod.

Dean posted some of his boring bars here - it might give you an idea. Dean, I hope you don't mind me posting the link...

A simple way of thinking about making a boring bar, is that the "head" profile must look just like a mirror image of an outside turning tool - and then cut off short and a shank attached at 90 degrees to it. Then any bits that will not fit into the hole must be ground away with adequate clearance. Mirror image, because you will be cutting in the "opposite" side.

If you want, give a shout, and I'll take a photo of some boring bars I have that's been ground from square HSS.

Regards, Arnold

 

[Dirty_Vinylpusher]

Thanks guys.

Yeah I'll be making mine from square HSS steel.
Pictures are always helpful ;D

 

[Dirty_Vinylpusher]

Well, here's my first attempt at making a boring tool.
Funnily enough, it looks nothing like any of the pictures I've seen here or anywhere else for that matter, but hey - it seems to work.

 

[arnoldb]

Good going DVP

;D If it works, it's right!

Here's a couple of photos of my motley crew of wild and diverse boring tools - I didn't include purchased carbide tipped tools; there are a load of pictures of those available:

Regards, Arnold

 

[Dirty_Vinylpusher]

Thanks Arnold.
Pretty good for a first attempt yeah.



Judging by your pictures there's no real rule on how to make these things, you just make them to suit the job?

I tried taking a couple of light cuts in mild steel as well and it worked ok.