# Taking a step back - Bit grinding



## Foozer (Nov 9, 2016)

I get caught up in 'Shinny Things' at times which if left unchecked leads to Oh Fudge . . . So a step back - Grind - Sharpen my own tool bits. Open the book, look over the idea and cobble something together. So with a hand full of bits, device to hold them [save the knuckles] it's a step back to the basics. Use the gizmo, learn how to use it and take it from there . . .


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## goldstar31 (Nov 9, 2016)

I too have been playing about with 'bits and things' and I was going to invest in one of those new fangled CBN wheel things.

So what is formula to get an angle on a grinding wheel- without a fancy thing a ma jig?

Actually, I found a note 'somewhere' and all that it requires is a simple formula or merely a constant.

So it is 0.0088

So if you want an angle all that you have to do is multiply the angle in degrees times the diameter of the grinding wheel times 0.0088 and the height or depth is the sum in thousands of an inch.

So 5 degrees on a 6" wheel is 

0.0088 x 5 x 6 is 0.260" or roughly 1/4"above or below the centre of the grinding wheel

If you have a tool and cutter grinding book it will probably be worked out already but I hope that this helps those who haven't
Cheers

Norman


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## Foozer (Nov 9, 2016)

goldstar31 said:


> So what is formula to get an angle on a grinding wheel- without a fancy thing a ma jig?
> 
> Actually, I found a note 'somewhere' and all that it requires is a simple formula or merely a constant.
> 
> ...



Good info - - sorta worked out center line of tool bit 0.375 above wheel centerline for 7 degree - Formula comes out to 0.369. It's a gizmo - should come in handy to touch up  bits. Free handing? Well . . . Playing 'Let Me Count the Many Facets' Ah No.

Now to build a better stand for the grinder and marry the jig to the base . . .


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## goldstar31 (Nov 9, 2016)

Foozer said:


> Now to build a better stand for the grinder and marry the jig to the base . . .


 
Glad to pass on a hint! I confess to having rather a large collection  of tool and cutter grinders but my old Clarkson is almost devoid of graduations.
The choice lay between sticking it - in bits- on a dividing head and then going through the tedium of graduating in this 'units, fives and tens' and then having to get my universal pillar tool out  to stamp the numbers.

Instead, I have one of these little square magnetic digital angle finders which seem to abound now. 

No prizes for guessing - is there?

I hope that this is also useful

Norman


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## Foozer (Nov 10, 2016)

goldstar31 said:


> Instead, I have one of these little square magnetic digital angle finders which seem to abound now.
> 
> Norman



'Shinny Thing!!'

Ophelia: 
 I shall the effect of this good lesson keep,
 As watchman to my heart. But, good my brother,
 Do not, as some ungracious pastors do,
 Show me the steep and thorny way to heaven;
 Whiles, like a puff'd and reckless libertine,
 Himself the primrose path of dalliance treads,
 And recks not his own rede.

I hear ya tho - Kinda go along to know more than I need to so when I forget what I don't really need to know, what is left is the muscle memory to do what needs doing. And if it gets too easy then I have more time for the 'Honey Do' list -
Ah No . . .


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## goldstar31 (Nov 10, 2016)

Nice to have a bit of culture to express problems!
On my wife's obituary, I penned the words of W.H. Davies and 'What is this life if full of care, we have no time to stand and stare and it finishes with 'A poor life this, if full of care, we have no time to stand and stare'

She was a close relative of Alice Pleasance Liddell who was 'Alice in Wonderland', played a mean 'horn' and was quite a dab hand at dental surgery as a FRCS( Edin). She taught me centrifugal casting-- amongst other things:thumbup:

So back to winding up a considerable estate and a bit of time now and again in my little workshop.

'Parting is such sweet sorrow'

Norman


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## Foozer (Nov 11, 2016)

goldstar31 said:


> 'Parting is such sweet sorrow'
> 
> Norman



 "Did he really want the warm room, so cozily appointed with heirlooms, transformed into a lair, where he might, of course, be able to creep, unimpeded, in any direction, though forgetting his human past swiftly and totally?" [Metamorphosis - Kafka]

Having recently lost my Father, now after 64 years of having one am faced with, for the first time in my life - Of not having one . . .
But do as must needs be, pull up the boot straps and as the eldest son step into the shoes vacant - 

And boy are my siblings in trouble with a dreamer like me at the helm . . .


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## chucketn (Nov 11, 2016)

Foozer said:


> I get caught up in 'Shinny Things' at times which if left unchecked leads to Oh Fudge . . . So a step back - Grind - Sharpen my own tool bits. Open the book, look over the idea and cobble something together. So with a hand full of bits, device to hold them [save the knuckles] it's a step back to the basics. Use the gizmo, learn how to use it and take it from there . . .


 
I, too, have that Harold Hall gizmo. Made for me by a good friend that is a retired tool and die guy. I built one myself, but it is nowhere as nice as the one my friend built. Purchased a HF bench grinder and put a diamond cup on one end and a white Alum. Oxide cup wheel on the other. Used it a few days ago to grind several lathe tools. Had to make a couple more accessories for mine, and will one day make a set of square mill cutter holders for it.

Chuck


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## stragenmitsuko (Nov 11, 2016)

I've got a Clarkson MK3 , and altough my graduated rings  on both the machine 
and the 3way vice are in mint condition , whenever possible I  use a digital angle gauge . Makes life so much easier . 

I also use this little gauge when setting a part in the vice for milling an angle . 
Especially if it doesn't have to be all that accurate . 

Pat


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## Trialnterror (Feb 8, 2017)

I'm so lost....... Tried to make out what's going on here but flew clear over me head!


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## Foozer (Feb 8, 2017)

"...how one lives is so far distant from how one ought to live, that he who neglects what is done for what ought to be done, sooner effects his ruin than his preservation" The Prince - Nicolo Machiavelli.

In the never ending pursuit of shiny things, one ought to step back on occasion to find the first shiny thing wasn't so dull after-all . . .


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## goldstar31 (Feb 8, 2017)

Il Principe? What all the great politicians kept as an aide memoire on their library bookshelf.:thumbup:


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## bazmak (Feb 8, 2017)

I must confess I am in the middle of complicated fiddle about thingummygigs
 based on and around the eccentric system all in order to try and find a simple 
and easier way to grind cutting tools.Start on one pathe and go off on different
tangents.Started with diamond /CBN wheels/discs lapps etc to a std grinder
As my thread I am in the process of making the eccentric eng system as well
as diverting with a no of different thoughts.Currently playing with a swivel table
with 30o (118o) fixture purely for drill grinding.Will update my posts when this heats dies down.We had 2 days of rain and now its 4 days of 42oc.For those of you in the Uk its about 150oF in my shed.So its close all doors and windows
leave the aircon on full all day while I watch THE WINTER OF 1963 on UTUBE
I had just started work that Aug and had to catch 2 buses to be there at 7.30
I was never late and don't remember it to be as severe as said.Maybe I was lucky or my memory is going
One memory I have left is my parents had a hot water bottle we kids had a house brick warmed
in the coal fired oven and wrapped in an old blanket.I remember scaping the ice off the 
inside of the bedroom window.Fortunenately we had indoor toilets


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## goldstar31 (Feb 8, 2017)

Barry,
           Perhaps you are confusing 'grinding' with 'honing'. The first removes metal which will leave machined work with the same marks as the grind gives. Honing gives a finish that used to be achieved after the 'rough to size' was completed on the lathe and then transferred to a grinder.  I suspect that you know this but I'm trying to clarify for those with less experience.
I think that BaronJ was thinking along these lines.- with a coarse and fine stone at each end of your project. Perhaps he'll comment.

Reminiscing, my late wife's tool kit has a normal fine-sh hand stone but she had a white Arkansas stone to finish off. Again, she had - and I have a collection of fine instruments which extra stones from horses' hooves and broken taps or whatever! It all may dated but most of our machines would not seem out of place.  

About weather, we didn't have problems with freezing in winter as the outside toilets or thrones, received coal ash from the kitchen fire and were emptied by the midnight mechanics. Unquestionably, there was a certain stimulus for self improvement. 

And a caveat not to eat yellow snow:hDe:. So consider a simple honing jig- there are numerous ones, Bradley, Goniostats and funny little chariots which run along an old fashioned oil stone.

Keep cool!

Norm.


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## bazmak (Feb 8, 2017)

Thanks for your input Norm.When I first started work in engineering
my hobby was woodworking and one of the first tools I bought
was an expensive 2 sided Indian oil stone for which I made a nice
hardwood box and I still have today.
,its done a lot of good work on chisels and planer blades,using one of those funny little chariots
With regards to my current project,i have fitted diamond wheels
and discs to a benchgrinder and as noted the 240g leaves tools looking like a ploughed field under a loupe.I purchased a set of 3 diamond discs 150dia
with the finest being 3000g.This is what I meant by honing.Not true honing
in the correct engineering description but should produce a similar finish
At what grit size does grinding becoming honing as regards finish
When I am up and running with my setup I hope to pass on my findings


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## Brian Rupnow (Feb 8, 2017)

All I have to add is---I was always taught that grinding on the side of a wheel as is shown in the very first post of this thread was very dangerous and could make the wheel explode. That type of wheel is not made to withstand side forces.----and--Bazmak--You had a brick or a water bottle. I had a dog named Boots. Boots was my official footwarmer all the years that I was a kid. She slept on the foot of my bed. Before we had a wood burning furnace that would hold a wood fire all night, we had an old iron box stove in the center of the house, which was not air tight and would burn out at about 3:00 in the morning. A glass of water left on the bedside table overnight would be frozen solid by morning. I think it was an Australian band that was called "Three Dog Night", so I assume that some parts of Australia get pretty cold in the winter too.---Brian


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## Foozer (Feb 8, 2017)

Might look one way, however, no side grinding - well almost never no side grinding . . .


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## bazmak (Feb 8, 2017)

Your warnings on using the side of grinding wheel is correct but only 
so far using a stone wheel and is not relevant to what I am using or doing
Also guards are  not really necessary the cbn or diamond wheels will not disintegrate as a stone wheel will.Your house was colder than my house Brian
You win,nuf said


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## Hopper (Feb 9, 2017)

The other thing with grinding on the side of conventional wheels is that once it clogs up, you can't safely dress it. I too was taught never to do it. Yet, it seems grinding on the side of the wheel has been acceptable practice in model engineering for several generations. Whether the Harold Hall rest or various articles by LH Sparey and Duplex and co dating back at least to the 1940s it seems to be surprisingly popular. My old foreman would have kicked their backsides right out of the shop if he caught them using the side of the wheel. 

The other thing we were taught as spotty-faced yoofs was to stand aside after switching the grinder on and let it get up to full speed a few seconds before stepping in front of it, because if the wheel is going to disintegrate it will usually do so as it comes up to full speed.

_I grow old &#8230; I grow old &#8230;
 I shall wear the bottoms of my trousers rolled.    
Shall I part my hair behind? Do I dare to eat a peach? 
I shall wear white flannel trousers, and walk upon the beach_
(TS Eliot)


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## goldstar31 (Feb 9, 2017)

As a rule of thumb answer to Barry's question about honing, My take is that it is when you can see the reflection of your dirty thumb in the reflection on the tool. I probably am repeating things but add that I normally paint a worn tool face with a black felt tipped marker to check the grind and in the same context, use a  dental mirror to check- without removing the work. Indeed, I use the magnifying variety but there are plenty of plain mirror ones that almost suffice.

Again, I wander around with a loupe on my bi focals that fits around the lens frame and folds back when not in actual use.
It was a present from Don. L. Ashton who wrote the books on Stephenson's and Walshaerts Gears- amongst the saxophone music for my wife. I'd like replace all three- but admit abject failure!

I've just dumped my Windows 10 for one of these all singing- all dancing Apple Mac's as the W10 system was as much use as an ashtray on a motorbike. Tucked away is this little Lidl woodwork grinder which I was going to modify. Oddly, it tilts into a vertical plane rather like the one described in Holzapffel those millions of years back. His disc was- walrus hide. Brian might have an Iniuit contact for a bit of appropriate leather!!!!

Cheers to all

Norman


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## Blogwitch (Feb 9, 2017)

If you couldn't grind on the side of a wheel, then very little would be done on commercial jobbing shop surface grinders, which mainly are the same wheels you use on an offhand grinder just a lot bigger at times.

Not only do you radius the edge of the wheels and the normal cutting face with a special rotary dresser, so that you can grind both external and internal radii, you also sometimes use an hand held square oxide stone to dish the side of the wheel leaving a cutting edge around the side periphery of about 1/8" to allow you to grind vertically down a face.

Sides are also ground when profiling wheels to allow cutting of profiles into very hard materials, how else are they supposed to do it?

Whenever I changed jobs, if there was any grinding machines in my new employment that I would be required to maintain or use, my grinding wheel certification wasn't transferable from job to job, a new 3 or 4 day course had to be attended to be re-certified each time, and at each one, wheel profile dressing was a major part of it.

John


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## goldstar31 (Feb 9, 2017)

Blogwitch said:


> Not only do you radius the edge of the wheels and the normal cutting face with a special rotary dresser, so that you can grind both external and internal radii, you also sometimes use an hand held square oxide stone to dish the side of the wheel leaving a cutting edge around the side periphery of about 1/8" to allow you to grind vertically down a face.
> 
> Sides are also ground when profiling wheels to allow cutting of profiles into very hard materials, how else are they supposed to do it?
> 
> ...


 
John is right, I have such a jig- came with my Clarkson.
As a bit of 'All our Yesterdays'  I did the testing of the modified rosins- in the early 1950's that made some of the wheels. There was too much dangerous stuff on free maleics and thallics and so on. Went back to 'bean counting' and retired with enough to manage some 31 years ago.

Well, I did read 'Ill Principe' amongst my other 'sauces' of information.


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## Blogwitch (Feb 9, 2017)

Norman has hit the nail on the head.

Over the years, bonding on normal wheels have become much better, and to burst a wheel nowadays really needs to be worked at, like hitting it with a hammer or dropping it on the floor.

When I first started 50 years ago, wheels were really fragile, wheel ringing was a common place thing to check for cracks and too much coolant penetration, and this is where the no side grinding on a wheel came from.

I am not saying that you should disrespect bonded wheels and their safety precautions, far from it, but side grinding is an operation that can be allowed to a certain extent without causing major problems. 
You are more likely to come to a sticky end if you try to fit a larger wheel than your grinder is designed for, smaller is no problem, but if you increase the diameter, the peripheral speed can easily go beyond the designed speed for the wheel.
I wince when I see people making up their own offhand grinder out of a motor that comes from goodness knows where and a wheel that has no history for it, most probably found in the back of their grandfathers old workshop, probably off a hand powered grinder.


John


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## goldstar31 (Feb 9, 2017)

Thanks John!

It's these newer washing machine motors which give me the willies. It was OK in a past decade with the old 1440 rpm 1/4HP things.
I've one- somewhere., which powered my Quorn until I got a proper 2880rpm  one. I tell a lie because I have another on my Kennet and , oops, one on the little Stent. 

'And one man in his time plays many parts'

Hope you are well

Norm


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## BaronJ (Feb 9, 2017)

Hi Guys,

Re motors used to power grinding wheels...

Common induction motors are not a problem, they don't normally run at more than 3000 rpm (3600 @ 60Hz).  Grinding wheels are commonly rated to 5000 rpm or higher.

Its universal motors that become dangerous with grinding wheels attached to them.  Spindle speeds can often be in excess of 15,000 rpm.  How many of you with Dremal type tools have blown up those tiny abrasive wheels at speeds much less than this. 

The other motors that can be an issue with very high rotational speeds are DC motors, many falling into the universal catagory.  Not that universal motors cannot be run from a DC supply.

Norman:  Yes I was infering that Barry's ability to swap the tool rest from one end of his grinder to the other in order to make use of two very different grit size wheels was very useful.


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