Grinding wheel choices?

[Naiveambition]

i am setting up a grinder station to grind my tools and have ?s regarding wheel types used.
First off I will be grinding lathe bits, drills, and possibly endmills. I have the Harold hall grinding jig book on the way to help with angles.
My question is more of what kind of wheel to use. Meaning cup, plate mounted, regular flat face.

The drill sharpener says to use the side of the reg. wheel, and while this may be ok by somewhere else, I am wildly uncomfortable doing this. I'm sure the front face would work with a rigid setup to eliminate flex, but if it ever does catch their will lots parts and pieces a flying.
So pre thought would be a plate mounted wheel to do drills, (prob. Alum oxide) and hss lathe tools. And a green for lathe carbide.
Am I correct that u only use the face of a plate mount wheel?
And as for endmill sharpening I'm guessing a diamond cup wheel, I may want to sharpen the side flutes later on as I get through Harold's book, but for now just the face.

 

[TonyM]

I was taught to use only the front of the wheel of a bench grinder. Using the side of the wheel was always a big no.
Toolroom wheels and how they are used is different because the cut is much more controlled than offhand grinding.
I am looking at setting up diamond wheels for finishing of my tools. Rough grinding if required using the bench grinder

 

[goldstar31]

I'm really going back to your previous dilemmas with boring tools - or whatever.
There is precious little to fault Hall's book except that things are changing and probably adding diamond and CBM would help you enormously.
However, I would suggest that you read and absorb John Moran's GadgetBuilder.com's web pages.
I've been over the text etc and - whilst I may take issue about the Deckel clone, you would benefit from the two simple jigs as starting points. The little amount of effort required to make and use them means that if they don't suit you that you haven't lost much.

Again, I strongly suspect that your previous efforts have been thwarted by your failure to do as Tom Walshaw wrote as Tubal Cain, it is all to do or not to do with that little bit at the end of the tool that matters.
I would seriously suggest that you 'black in' the little bit with a waterproof marker and hone it away with diamond paste or film. Conrad Hoffman - I've mentioned him before- gives a blow by blow discourse in his Advanced Tool Sharpening site.

If you want to make turnings which are barely dust and your work shine as well as 'mike' try Walshawand Hoffman.

I think that attention to the final honing would help you enormously.

Let me know

Norman

 

[Entropy455]

For sharpening brazed carbide bits, use a green Silicon Carbide wheel for rough shaping, and a Diamond wheel to dress the finial cutting edge. (bench grinder with each wheel type per end). For sharpening HSS bits, use aluminum oxide wheels only (bench grinder with one coarse and one fine aluminum oxide wheel). Do not sharpen HSS with Silicon Carbide or Diamond wheels.

Never grind on the side of a grinding wheel unless it’s specifically advertised as being design/rated for side loading. Bench-grinding wheels designed for cutting on the side, in lieu of just the outside face exist, but these are not common, and typically cost more.

Custom sharpening equipment will use custom wheels (cup, plate, other. . .) whereas bench grinders use standard wheels. The advantage to custom sharpening equipment is that there’s normally precision jigs for tool positioning. The disadvantage to custom sharpening equipment is the high cost.

http://www.grizzly.com/products/Grizzly-Universal-Knife-Grinder/G2790

Grizzly sells a sharpener for use with side-loaded wheels. They also sell just the wheels. This unit (linked above) is intended to sharpen planer and jointer knives, but can also be used as a side-loaded bench grinder wheel.

 

[goldstar31]

ITMA!

I have a CBN wheel with a 160 grit which will do both hss and carbides. Using a green grit is a first class way to fill the workshop with clouds of grit.

As for steel and diamonds and the alleged destruction of the carbon with heat, it is simply an old wives tale and sadly Entropy has joined the knitting or nothing circle.

Here again, practice and theory differ. With care, a worker with little experience can use diamonds and more importantly, create a mirror like tool edge which- as we know( or not) impart and equally mirror-like finish to the work.

What has to be avoided is the negative tool angles often on cemented carbide inserts which give the necessary rigidity and horse power to push away unwanted metal. I have no doubt that the normal home workshop small model maker's lathe does not have either attribute .

Again, I am writing for the amateur and not for those who sadly have to earn their pennies on large machines. Someone has to but this is a hobby- no more.

Years ago, I actually made bonds for abrasive wheels and also help design tungsten carbide cutters for cutting
rockwool- for an American company who was having problems on their Dankhaert machines . Happily, not sadly, I put my sliderule away and went on to playing with counting beans for a while until I said 'Enough, I have enough' and raised two middle aged fingers to having to work- for someone else.

Incidentally, I have a Clarkson, a Quorn which I made, a Kennet, a Stent that someone made by welding( and died) and I'm playing with one of these Chinese Deckel things with two types of diamond wheels and a 80 grit ordinary wheel. I also dabble in Goneostats and ornamental turning but I'm writing for a young? person with limited experience and success.

Yah Sucks??? Is that the expression?

Norm

 

[Entropy455]

---and sadly Entropy has joined the knitting or nothing circle.

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Another condescending & passive-aggressive *** - real classy...​

Naiveambition, it's best to use some sort of dust collector system when using grinding wheels inside. A shop-vac with high efficiency filter works well. Another option is to use a small duct & blower, and simply discharge the air outside (what I do for welding fumes, and grinding dust). If you live in an area with nice weather year-round, you can always put your bench grinder outside under an awning.

I'm not sure what goldstar is referring to with diamonds and heat??? Aluminum oxide sharpening HSS just fine, and diamond wheels are quite expensive.

 

[goldstar31]

​

Another condescending & passive-aggressive *** - real classy...​

I'm not sure what goldstar is referring to with diamonds and heat??? Aluminum oxide sharpening HSS just fine, and diamond wheels are quite expensive.

Not bad for a kid who left school at 14 after what was a miserable war time education- so Thank you!

Diamonds are pure carbon and therefore there is a faction that claims that the heat generated in grinding a diamond wheel will be quickly destroyed. I amongst many others does not subscribe. As for price, diamond or more correctly synthetic ones is remarkably cheap and if you had followed the excellent advice of Bazmak ear lier you would have read how cheap these wheels (and- pastes) are.

When they were dear, my first one came from a firm which shaped lenses and somewhat tenuously, my wife who was a Fellow of the Royal College of Surgeons played bari sax with an optician who played base clarinet who had an 'in' with the local optical works and -- I wasn't one to miss an opportunity! Sadly, neither person is now with us but the diamond wheel is . I went back to help an nonagenarian who had built a 'Long wheel base' Stent tool and cutter grinder and he still has his. We often re-sharpen TC masonry drills- being Old Age pensioners and short of disposable income. ( Ahem!)

So that NA if you are still with us, I suggested that you access Gadget Builder.com and he built a Brooks -Stent from the writings of Derek Brooks and was published in Model Engineers Workshop issues 16 and 17.
I still have copies on file. But reading on, Brooks used his machine to grind needle valves for his model engines.
I have the 'short ' Stent which was weld fabricated from mild steel sections and like the misconceptions of steel rubbing against steel works remarkably well.

So NA, you have long and hand on experience.

Norm A

 

[DJP]

I built a grinder and jig using a cup wheel to sharpen milling cutter end flutes. My conclusion is that 80% of the result is obtained with 20% of the effort and that is sufficient for my level of hobby machining. Twist drills can be sharpened off hand and carbide bits returned to shape with a green wheel.

These are all low budget solutions but acceptable to me without the need to buy a new cutting bit when the old ones become dull or chipped.

My thoughts for the discussion.

 

[BillWood]

Hello,

I have recently started using a diamond disk, they seem to work very well with HSS and are discussed in various forums on the internet, you can get the tiny little ones for use on Dremel type tools of the big 6" ones for use on bench grinders

Fairly cheap compared to AlOx wheels.

Try here for starters to have a look at what is available

https://www.ebay.com.au/str/THK-Diamond-Tools/Diamond-Flat-Lap-Disc/_i.html?_storecat=3920503013

Worth browsing the other products whilst you are there.

I use a 6" one backed up by a disk of MDF - you could use steel or even a Alox wheel as a backing plate - then maybe you could "safely" grind on the side of the wheel and have the other bit as well ?

I have used one of those little 4" "diamond" cups for $5ish but the word is that they are CBN not diamond but who cares ? However I fairly quickly rubbed all the diamonds off the resin. Like anything there will be good quality products and bad quality products $5 was probably too cheap. Other people have reported they have had good use out of these little wheels.

https://www.ebay.com.au/itm/100x20x...=item4d84218b12:g:tzMAAOSw~xtcCNX1:rk:89:pf:0

Bill

 

[goldstar31]

Bill
Even with a $5 wheel wearing out quickly, it is still cheaper than replacing cheap carbide tips.
Regarding your rather odd configuration prompts me to mention that it could have been converted to utilise a series of progressively finer grades of synthetic diamond pastes driven at a safe speed.

It isn't new or whatever, in the days of first lathes like Maudsley's and Holzapffel, people graded their own grits and used them on walrus hide. My father used a long leather belt impregnated with stuff from corroding lead ingots to do his own hollow ground cutthroat razors. None of the forgoing would be acceptable today but there is the grain of a sensible practice.

As said earlier, I have a couple of Myfords but when I bought a Vertex dividing head and tailstock, I got an undrilled cast iron face plate- and I often squirt a drop or two selected grade diamond paste, spread out with the help of a little more lard oil and get the mirror cutting edge by driving it on a lathe spindle nosewhich I suggested earlier to Naiveambition.
It may not follow accepted engineering practices- but it did.

Cheers

N

 

[Naiveambition]

Thanx everyone one for their posts. Goldstar, As I've been working thru the issue of cutter grinding, I have noticed a few issues with the lathe. My setup for gearing is 40 threads per inch, and what I'm seeing is the actual thread using a non threading tip. My finish is very consistent just not slow enough feed. When I did a inline boring, my tool had a flat point wider than the 40 tpi, and it gave great results.
So as I work on a finer feed, I need to sharpen my drills. The end mill sharpening is to hopefully save some money. I do have a bad habit of not closely following feeds and speeds and tend to dull my milling cutters prematurely. Inexperience obviously, but if the machine isa shaking I back her down. Surely that transmits to the work.
I have pretty much every time honed my tools but am still missing that sweet little move that brings it all together. I felt I needed a more controlled approach to grinding offhand. I have done it, but with a 1-10 ratio Drill bits- well let's not even go there
I plan a dedicated grinder for mainly drills and lathe tools. And a toolpost grinder adapted to another setup similar to a cutter grinder.
Although completely off the post I would like to say that I love learning from older fellows with the experience, and freely giving a lifetime of knowledge to us inexperienced ones. And as there will be disagreements among the posters, we must remember we all messed up along the way. I've been told while learning, you often learn more of what not to do than what to do. This site to me is like having a thousand grandparents that know machining, so keep it up

 

[goldstar31]

NA- I hope that by now that you are making one of the simple jigs which will avoid you rounding off cutting edges. Probably you should scrap both wheels which came with your double ended grinder and substitute something like a CBN wheel at one end and a softish 80 grit at the other. Then scrap the usually hopeless rests with something stronger- and bigger.

I've got the machines but often cheat with a 600 grit diamond flat 'stone'- by hand. This is generally what the old hands do but I suggest that you avoid such measures as you are learning.

As for cutting threads of 48 tpi, surely there is a mod or arrangement to make finer threads. Maybe a better banjo which will take another set of reducing gears in the banjo.

Keep me posted

Norman

 

[BillWood]

Bill

As said earlier, I have a couple of Myfords but when I bought a Vertex dividing head and tailstock, I got an undrilled cast iron face plate- and I often squirt a drop or two selected grade diamond paste, spread out with the help of a little more lard oil and get the mirror cutting edge by driving it on a lathe spindle nosewhich I suggested earlier to Naiveambition.
It may not follow accepted engineering practices- but it did.

Cheers

N

Goldstar,

I am interested in your honing process - what grits of diamond paste do you use ?

I did a scraping course in Melbourne a few years ago and the process you describe above was how they sharpened the carbide scraper blades.

I have had people tell me that after honing they can shave a hairs off their arm with the honed HSS tool, I have never been able to do this and honing has always been a bit of a mystery to me. I searched previous posts and note that you recommend Ian Bradley's book Shaping Machine and Lathe Tools but that is very hard to find at a reasonable cost at this moment.

Bill

 

[goldstar31]

Greetings Bill and Thank You for your comments.
Years ago, I bought a collection of syringes from Ebay. I tend to use the green stuff but obviously there is finer stuff.

Certainly, there is the ability to shave hairs.
Really, you should have a number of hones impregnated with the various grades and work from coarse to the finest. It's rather like using. a succession of graded abrasive papers when doing a car repaint.

Going back to Bradley, he also wrote 'The Grinding Book'. Again, a bit old fashioned but golddust.

Incidentally, Connelly's Machine Tool Reconditioning is available on the net.

Does this help

Norman

 

[Entropy455]

I spoke with a toolmaker at work yesterday (these guys sharpen tooling for a living). Carbide bits are sharpened with Silicon Carbide wheels, and final polished with Diamond wheels. HSS bits are sharpened with Aluminum Oxide wheels only. If a fine razor's edge is needing on an HSS tool, they final-dress it with a CBN wheel (which looks identical in construction to the diamond wheels - obviously a different abrasive material). I asked specifically what happens if you try to cut/polish HSS tooling on a diamond wheel. He said "HSS will gum-up a diamond wheel." I forgot to ask how they sharpen
cobalt bits.

Interestingly, they've got about 30 sharpening machines in the toolmaker's bay (about 20 x 150 foot room). Only three machines have a coolant provision. Everything is normally cut dry, where the wheels turn fast. There is a central dust collecting system that draws air in parallel from the wheels of each machine (with exception of the water-cooled machines).

 

[goldstar31]

My electric and gas are off and being annual serviced.

So a bit more

I suggest that you Google Home Shop Machinist- or join and add 'diamond pastes'

One is Mirror Finishes- Fact or Fiction. You'll enjoy it.

I might come up as Ravensworth2674.

There's a helluva a lot of good but old stuff on tool and cutter grinder


Cheers again

N

 

[BaronJ]

Hi Naiveambition,

i am setting up a grinder station to grind my tools and have ?s regarding wheel types used.
The drill sharpener says to use the side of the reg. wheel

I'm a bit late into this thread, but never mind

As far as using the side of the wheel is concerned, it is not a problem !

Consider that you are grinding a drill on the side of the wheel, the forces are so low as to be almost non existent. Now if you were doing something that required heavy pressure, certainly more than just sharpening a drill, then that would be a definite NO. Use the front of the wheel.

 

[BaronJ]

Hi Bill,
JMTPW,

I have used one of those little 4" "diamond" cups for $5ish but the word is that they are CBN not diamond but who cares ? However I fairly quickly rubbed all the diamonds off the resin. Like anything there will be good quality products and bad quality products $5 was probably too cheap. Other people have reported they have had good use out of these little wheels.

I have and have used several of these 100 mm cup wheels. I've found that they could be either diamond or CBN. I think the problem with the diamond ones, is that people use far too much pressure and simply rub the diamonds off. The CBN ones seem to be a matrix of abrasive embedded in the carrier, and seem to survive better. The other thing is they are often run too slow. Somewhere around 5K rpm is a better speed, but most people put them on an induction motor shaft running at 2800 rpm. Certainly for tool sharpening the higher speeds are preferred.

 

[goldstar31]

I was thinking about the tool and cutter grinder that Eccentric Engineering sells.
Bazmak made but there is an interesting video of the designer using a Double Ended 6" grinder with a softish stone??? 80 grit and a CBN on t'other.

For the helluv-it I bough something similar from axminster tools and chucked a 36grit paving stone off one end and substituted a 160Grit CBN .

And then I had a recall of memory and probably the cheapest and easiest to build- for Canuks and the US is Norman Tinker's Tinker - plans from Canada. Can be made from bar metal as well as castings.

Me? No but I have the placed littered with tool and cutter grinders already

 

[ignator]

Norman Tinker's Tinker

Is this what the Tinker tool and cutter grinder attachment looks like? (found at http://www.lautard.com/tinker.htm)

I found this on Lautard.com, which I found from 2006 posts on home shop machinist web site when searching for "Norman Tinker's Tinker" you referenced. They comment on Lautard getting a copyright to Tinker's design.
It appears even there some heated discussions of proper use of bench grinders.
I've owned a cheap Double ended grinder I purchased from a now defunct machine tool seller (Enco) many years ago. It came with green Silicon Carbide wheels. Which would erode away with very light grinding use. So I replaced them with diamond wheels that Enco had on sale. They still are usable, but the fine grit looks almost clean of any diamonds.
I use this for mainly brazed insert carbide. I don't know if it's because I'm overheating the carbide, but I typically don't see the same life once re-sharpened, and chipping seems to be an issue. I found quenching in water to be a big mistake with carbide. I do some HSS on the diamond wheels as well.
I'm probably doing everything wrong per some posts in this thread, but I'm not too old to learn a correct way.