Lathe tools

[ukracer]

Yes I'll take a pic of it tomorrow. I bought the discs for sharpening carbide scrapers but they also do a great job on lathe tools.



Grind the top of the tool at a sharp angle down away from the edge, to form a more knife-blade cutting edge. It will slice through softer materials instead of brute forcing the material away. The results will surprise you when you first do it.

So more like what you would use to cut plastic . I thought I knew what you meant
But terminology is awkward as if I was explaining it in English I would say a high rake is less rake but it's measured from the 90degrees so a 2 degree rake is lower that a 15 degree rake.

I am guessing any one starting out would end up confused....like I used to.

 

[Pete.]

High rake would mean more angle. Zero rake tools are flat-topped.

 

[optima21]

in the days before the internet, the "model engineers handbook" was about which included a section on machining materials (from page 84 onwards) including cutting angles for hss tools for different materials

http://chiclassiccomp.org/docs/content/books/TheModelEngineersHandbook_TubalCain.pdf

 

[Hopefuldave]

Well chaps thanks for all your replies,further digging in the box of bits that came with the lathe there are several bits of 1/2 ins hss tools,these have been extensively ground to make them usable, as Pete sez 1/ 4. 3/8 is the max tool size, after lots of pondering Ihave come to think that a quick change tool post isn't what I want

In my opinion, best thing since sliced smoked salmon - I got a Ch*n*s* one and a hatful of holders, once adjusted the tools swap in seconds and are dead on centre height

more a quick means of shimming ,folding wedges perhaps.

When I worked at a place where the boss was too tight to buy a QCTP, I used to keep the shims with the tools once I'd got the right stack to get them on centre height, with a rubber band holding them together - a lot quicker than grovelling in the swarf to find the ones I needed every time I changed the tool!

The toolpost I have isn't so much a post more a clamp directly on to the top slide ,any post fitted would have a thin bottom plate in order to allow any tool to be at centre height,have seen 1/4 hss blanks on the bay so ordering some and will progress from there,
Chris

Good move on the HSS blanks, that lathe probably doesn't have the speed, rigidity and power to properly work carbide - it likes heavy cuts. As already mentioned, the brazed carbide sets form the "machine" importers are as much use as a putty chisel, need to be reshaped and sharpened before use (so green wheel for roughing, diamond lap/wheel to get an edge). Hss can be sharpened on a normal Alox wheel, honed on an oilstone for a proper edge.

Have a google for the Southbend "how to run a lathe", there are a few editions downloadable as PDFs, it's a good primer for the new metal lathe user!

Dave H. (the other one)

OH! by the way, next you'll want a milling machine, and a bigger lathe, and.... I know, I'm still looking for the milling machine! See what Friday brings...

Dave H. (the other one)

 

[rosinante]

Hi all ,well done a bit of reading and playing found some bits of steel from an old machine, sort of designed,copied , and bodged somebody elses good ideas, the rough idea was to make a block which would carry 2 tools and be height adjustable with some m10 cap head screws ,the tools held with M6 cap heads,I went about it the hard way of course, found a home made boring bar in the box of bits, cut off and ground a bit of a 4 mm drill bit as a cutter and opened out the existing hole to suit a piece of the clamp bar from my morticer,faced of the angle ground ends of the bar and block.Very happy as it is a good fit drilled it thru 10mm to allow fitment and then realised a simple 10mm hole would have done,doh!!!.
Next was milling a slot, mounted the block on the top slide,easy I thought ,of course the travel of the slide wasn't enough ,allsorts of ideas went thru me little brain, in the end removed and refitted the top slide at 90 deg by moving the t bolt clamps outside the slots and backing the with some tool blanks. Put a milling cutter in 3 jaw chuck and went at it slowly, when it was deep enough removed block and put a big washer underneath to raise the block a bit then recut with the mill,ended up with a slot 1/2 d x 3/8 ,main cocktail up was the chuck hitting the top slide scale,doh!
Had enough today,beer oclock

 

[rosinante]

Hi again ,well here is the finished adjustable height toolpost, no plans or drawings just an evolution of a rough idea and coping with the errors, holds 2 tools and the inner 4 cap head screws are for adjustment to centre height

 

[slim_boy_fat]

Well done!! I like the idea of an adjustable centre height.

 

[Kram]

This is the type of wheel I use. http://r.ebay.com/YFiCMT
You have to remember this is for honing the edges only. If you try to grind a tool with these discs you'll wreck them right away.

Why do you use those? Mine is this type www.ebay.co.uk/itm/231802871611 They take a lot of abuse, Ground many cutters and drills...hardly touched the surface of wheel. It is very quick and gives a very sharp edge.