Shopping List for New BUD Owner

[MCKDAVID]

usually with difficulty. basically it depends on how it's broken, sometimes you can break them up / back it out with a centre punch if you can get enough of it too hit

 

[addjunkie]

Dont snap it, your either driving it too hard dry, or drilling too deep, dry and its picking up.

 

[Pete.]

Next time i snap a centre drill, how do i get it out without mangling another drill bit?

Ironically - with a snapped centre drill. Grind the end off flat then grind a slot through the middle the width of the broken tip and use the remaining tool to over-drill the broken stub.

 

[addjunkie]

usually with difficulty. basically it depends on how it's broken, sometimes you can break them up / back it out with a centre punch if you can get enough of it too hit

On the odd occassion this works buy a lottery ticket!

 

[dazza]

Thanks guys i've bought some better centre drills so hopefully will not happen as much.

 

[MCKDAVID]

Hehehe, aye addjunkie, yer right enough, probably more luck with thé lottery... At least then you could justify thé spark érosion kit to get it out easier.

 

[dazza]

Grinding the tools takes ages.

Went for a simple one first is this sharp enough? I left the grinder stand flat should i have put an angle on it?

 

[MCKDAVID]

check out tubalcain on you tube, he does an excellent series on how to grind all sorts of lathe Tools including really well done models of all the angles etc.

 

[addjunkie]

Thats a thread cutting gauge your using. You need to read up on lathe tool sharpening, understanding rake etc. Nd dont let the tool colour, keep dipping it in water.

http://www.steves-workshop.co.uk/tips/toolgrinding/toolgrinding.htm

 

[Pete.]

Did you grind that tool all the way back on the top? No need for that, you're just weakening the tool, putting in a load of heat, wasting time (and grinder wheel) and making more work if you need to grind the tool a different shape. Threading tools go in just a few mm, so that's all that needs to be ground.

Apart from that it's not a bad first attempt. You need to go again and put in some relief on both sides - 7 degrees is a good angle to aim for. Tilt the rest about 5 degrees and the curve of the wheel should give you a couple more.

Also your wheel is visibly blunt. You need a dressing tool.

 

[kcchan]

Not sure if it'd be more useful in another thread or not but what type of wheel dresser would people recommend? Type and brand if there's much in it?

 

[dazza]

Thats a thread cutting gauge your using. You need to read up on lathe tool sharpening, understanding rake etc. Nd dont let the tool colour, keep dipping it in water.

http://www.steves-workshop.co.uk/tips/toolgrinding/toolgrinding.htm

Yep i thought a thread cutting tool would be a good start as some of the others are a little confusing.

Did you grind that tool all the way back on the top? No need for that, you're just weakening the tool, putting in a load of heat, wasting time (and grinder wheel) and making more work if you need to grind the tool a different shape. Threading tools go in just a few mm, so that's all that needs to be ground.

This is an old tool i got from hood, i only put the 60º on it the top was already ground, it was that colour when i got it. I have some new tool steel arriving but thought i would practice on some of these bits.

Also your wheel is visibly blunt. You need a dressing tool.

I did hit it with the dressing tool, i think its just a crap wheel, i have a green wheel to go on.

 

[Pete.]

Green wheels are no good for HSS, don't even try it. Look for a good Aluminium Oxide wheel.

 

[dazza]

Green wheels are no good for HSS, don't even try it. Look for a good Aluminium Oxide wheel.

Do they have different Grits what should i be getting?

 

[brightspark]

Do they have different Grits what should i be getting?

a course and a fine one

 

[Pete.]

What size grinder do you have?

EDIT I see you have a 6" grinder with a 1/2" shaft. I'd go for something like a 36 to 46 grit soft wheel for roughing and a 60 or 80 hard for finishing a nice edge.

 

[dazza]

Thanks guys, should these only be for grinding the lathe tools or can i use them for other things as well?

 

[Wedg1e]

Just a quick aside and regarding grinding wheel types... I needed to reshape a brazed-tip carbide boring bar (so it would cut on the opposite face, i.e. not the wall of a bore! ) but I was down at Nursy's place and my green grit wheels are on a grinder at my house 12 miles away. I realised that for months I've been looking at a 4-sided diamond-coated sharpening block (from Aldi, cost a fiver) on my bench and thought it was worth a shot.
Picked the coarsest side, gave the carbide a few good strokes and away it went, cut like a charm!
I'm thinking diamond wheels might be a way forward...

 

[Pete.]

Thanks guys, should these only be for grinding the lathe tools or can i use them for other things as well?

I sharpen my pencil on mine. The wheel lasts ages doing that - the pencil not so long

 

[Hood]

Just catching up with this thread so commenting on the post from a while back. Best way I have found to get snapped centre drills out is to put a carbide milling cutter in the tailstock chuck. Cobalt will not work, needs to be carbide, just have to be canny as carbide is easily chipped, so semi lock the quill on the tailstock to try and reduce any sideways movement and keep the quill stick out as short as possible.


Regarding the discolouration of the tool, likely it is rust as they are old and were out in the damp cabin I have out the back of the workshop.

dazza, I think that book had a section on grinding tools, if not it must have been in the other one I can't find.