Grinding on the side of the wheel

[ChrisHParticipant @chrish]

Thanks for that David – I think I will try a diamond cup wheel from Arc and see how I go – as you say, they won’t break the bank.

Chris

[Sub MandrelParticipant @submandrel]

My Arc diamond wheel has has only moderate use, but the outer edge still looks as sharp as when new.

 

What do folks use as lubricant? For a small light task I go dry, larger cuts I apply a tiny amount of parafin with a small paintbrush (note that cutrs are small and it runs cool so thermal shock isn’t an issue like with a big grinder)

 

Neil

[Tony Pratt 1Participant @tonypratt1]

Neil, you really don’t need any lubricant for your grinding tasks. I would suggest using an extractor though or wear a face mask to protect your lungs.

Tony

[Sub MandrelParticipant @submandrel]

Thanks Tony,

 

I never though of that, but the dust is incredibly fine.

 

Neil

[Cyril BonnettParticipant @cyrilbonnett24790]

I have a small book ‘ Handbook on Tool Room Grinding’ printed by Norton Abrasives of America. 1938

Its quite a comphrenensive hand book on grinding, from it

 

“Side Grinding”

 

Grinding on the flat sides of straight wheels is often hazardous and should not be allowed on such operations when the sides of the wheel are appreciably worn thereby or when any considerable or sudden pressure is brought to bear against the sides.

 

Still trading

http://www.nortonabrasives.com/

 

Cyril

[NJHParticipant @njh]

Hi John

 

Well just as the answer of a diamond wheel is emerging as a favourite you throw the brake dresser into the pot! Now given that I ‘aint going to spend £1K, £500 or even £150 on this bit of kit what are the options? Are we back to grinding on the side of a standard wheel? Any advice would be valued.

 

Regards

 

Norman

[David LittlewoodParticipant @davidlittlewood51847]

Brake dresser? Never heard of it until today; presumably for wheels made entirely of diamond/resin composition. The Arc wheels are aluminium with a small layer of diamond composition, and mine was decently balanced when I fitted it, and its nature is such that I have not needed to dress it at all – though bear in mind my comment above about the fairly light use it has had. Look, the wheels are cheap, are almost all aluminium and thus cannot fragment in any normal use, so just try one and see how it works.

 

David

[blowlampParticipant @blowlamp]

Take a look here http://www.arceurotrade.co.uk/projects/d_wheels/dwdoc.html

 

 

 

Martin.

[Billy MillsParticipant @billymills]

Agree with David, I have used diamond wheels for several years on HSS and carbide and am very happy with the performance. I use the wheels to keep sharp tools very sharp, I don’t attempt to do heavy metal removal, just maintain edges that are little worn.

 

The use of Brake Dressers is crazy for home workshop use. Like buying a T & C grinder for sharpening small twist drills- totally uneconomic, better to buy new wheels or drills.

 

The diamond wheels that I have bought from the well known suppliers run very nicely as you might expect from the way they are made by CNC machining. In contrast, sintered wheels have to be dressed true because sintering is a much cruder process.

 

I looked at the Childs site. I am a long-term Tormek user which is a slow speed wetstone machine for sharpening steel. I cannot agree with some of his comments about this machine. I am a very happy user of wet stone machines -indeed I now have two set up for different jobs.

 

 

I know a number of Professional woodworkers who use these kind of machines to keep their HSS edges razor sharp, it takes moments to do and the sharpness is way beyond any tool as supplied. The machine is expensive however it has clones that are affordable These machines are designed for side stone grinding, the side is flat and the stone very wide, rotation is about 120 rpm.

 

Billy.

[Harold Hall 1Participant @haroldhall1]

First Len, an apology for not taking up
earlier your wish for my thoughts on the subject of this thread.
Whilst I visit the forum quite often to acquaint myself with the new
subjects being discussed I rarely find the time to read them all in
detail. Having now found your request I will attempt to give my
thoughts on the subject, I hope not too late.

Firstly, in a nut shell, I have never
considered grinding on the side of a wheel to be a total no no. This
though based on using it for tool and cutter sharpening and any other
task EQUALLY light.

Cyril’s comments from his Norton hand
book are very interesting in that they do not consider it totally
unacceptable. Similarly, my Universal Grinding Wheel Co handbook
(1989), whilst warning against using a wheel for heavy tasks, it is
not adamant that they cannot be use for lighter tasks.

My advice therefore is, that it is OK
for tool and cutter sharpening and anything of a similar duty. This
will though result in the need to dress the side of the wheel from
time to time, though in the home workshop not that often, reducing as
a result its width. It is impossible for me to be exact, but as a
guide line I would suggest, that when a 16mm wide wheel had been
reduce to 12mm it is time for a new wheel, and definitely no heavy
grinding work to be undertaken on it, front or side.

If your workshop activities include
dressing welds and rough castings then these are tasks for the outer
diameter and would recommend two grinders, one for rough usage and
the other for tool sharpening.

 

In this case, equip the grinder with
wheels specifically made for the task. These have a white grit (not
sure at the moment of the correct terminology) and cut so much better
that the wheels for every day use. They could then be Cup and Saucer
wheels, these shapes are beneficial but not essential. See
http://www.homews.co.uk/page225.html

 

It is worth noting that if sharpening
tools is done using a tool and cutter grinder or one of my grinding
rests, most sharpening is neither done on the outer diameter or the
side but the corner of the wheel.

Something a little more technical

Most will realise that when removing
metal with an abrasive the larger the surface the greater the
pressure required for the abrasive to be effective. Taking then a
simple example of grinding the end of a 20mm square bar, (400sq mm).
If though it is applied to the outer diameter of the wheel it will
only be a line contact, say 2mm wide (40sq mm)

With the workpiece is then applied to the side
of the wheel, not only will it be using the wheel in its weakest
plane but much more pressure would be required. Hence the reason for
it not being acceptable to use it in that way.

Another point worth considering is that
many off hand grinders do not have wrap around rests so there is no
support for the workpiece on the side of the wheel. This must be
attended to even for tool and cutter uses.

Finally therefore, using the side in my
estimation, tool and cutter sharpening with suitable rests, OK, heavy
duty tasks, NO!

Harold

[David LittlewoodParticipant @davidlittlewood51847]

Harold,

 

I am surprised by you comment that most cutting on T&C grinders is done on the corner of the wheel. Most of the time I use my Clarkson I use the face of the cup wheel; the carriage can be turned to an angle to move diagonally WRT the wheel and thus use the corner, but this is only ocassionally used for special purposes. Virtually all normal work is done straight across the face. This also goes against your point about the pressure, since only the leading part of the tool face being ground is in action at one time. It doesn’t matter whether the tool is 2 mm wide or 20 mm wide. To be fair I suppose its height does matter somwhat, but as one is only taking something like 0.05 mm cuts the actual force must very small.

 

David

[Harold Hall 1Participant @haroldhall1]

I think David you may have misunderstood my meaning of grinding on the corner of the wheel.

First, I must ask, if you are traversing the face being ground across the flat on the end of a cup wheel, how do you get it so accurate that is does not plunge into the face of the wheel any thing less than perfection in one direction will result in this.

My understanding, and the method I use and advocate, is that to avoid this the traverse direction is set deliberately to an angle of around one degree in a direction that results in the face being ground moving away from the wheel. In this case the grinding is only being done on the wheel’s corner.

If you have any data to the contrary I would be interested in seeing a copy.

On the subject of pressure applied I was only intending to refer to heavy duty grinding, weld dressing for example, perhaps I did not make that clear but not many home workshops would grind 20mm square tool bits

Harold

[ChrisHParticipant @chrish]

Harold,

 

I was very pleased to see you had joined this debate and very interested in your posts.

 

However, in spite of what you said re grinding on the corner of the wheel I have a query. A diamond cup and/or saucer wheel such as ArcEuroTrade supply have a wheel width of only 10mm max, and a depth of “grit” of only 3mm.

 

Would you still advocate grinding across the corner of such a wheel, or across the width?

 

ChrisH 

 

Edited By ChrisH on 15/01/2012 20:34:59

Edited By ChrisH on 15/01/2012 20:35:21

[Clive FosterParticipant @clivefoster55965]

Further to the grinding of lathe tools using a cup wheel the instructions for the Boxford T&C grinder specifically call for the face of the cup wheel to be dressed at an angle between 5 & 15° so that all cutting is done with the outer corner. It doesn’t take much wear of the corner before grinding efficiency and finish quality deteriorates.

 

A previous owner of my Clarkson kindly marked the 10° offset for dressing and and 90° to spindle for grinding positions on the table pivot which makes things very easy. Presenting the tool to the flat face of the cup wheel, as I mistakenly did on first trials, has depressingly poor results. In contrast the cup wheel on my standard bench grinder works quite well when the tool is presented to the dressed flat face.

 

I guess heavy grinding for rough shaping is less common these days. The thin cutting disks for angle grinders which provide a faster and less messy way.

 

Clive

[Harold Hall 1Participant @haroldhall1]

Your comments from the Boxford book Clive are interesting and essentially are the same as I adopt to ensure the tool does not run into the flat surface. In Boxford’s case, they angle the face of the wheel and I set the traverse direction at an angle giving essentially the same result. Five to fifteen degrees does though seem rather a lot and may be why the corner does not last long. I rarely dress mine but perhaps you do more sharpening than I do.

Initially, I was working with a standard wheel and creating an angle on the side of this would have been unacceptable, and of course, most who use my grinding rests are likely to be using such a standard wheel.

I think Chris you have misunderstood grinding across the corner which I am attempting to describe. You would be traversing the cutter past the flat face of the wheel, but as it is approaching at a small angle it would be grinding just on the corner.

The amount being ground will be very small, say less than 0.1mm so 3mm will be more than enough.

My web site has grown at such a speed recently that I have just realised that I have included pages on tool and cutter grinding. I would suggest going to the following link, then taking the link to the last page and calling up drawing one which shows the tool approach angle.

 

http://www.homews.co.uk/page224.html

 

I should add that I am talking about assisted sharpening, sharpening by hand will be different.

Harold

[David LittlewoodParticipant @davidlittlewood51847]

Posted by Harold Hall 1 on 15/01/2012 20:19:33:
I think David you may have misunderstood my meaning of grinding on the corner of the wheel.

First, I must ask, if you are traversing the face being ground across the flat on the end of a cup wheel, how do you get it so accurate that is does not plunge into the face of the wheel any thing less than perfection in one direction will result in this.

My understanding, and the method I use and advocate, is that to avoid this the traverse direction is set deliberately to an angle of around one degree in a direction that results in the face being ground moving away from the wheel. In this case the grinding is only being done on the wheel’s corner.

If you have any data to the contrary I would be interested in seeing a copy.

Harold,

I clocked the rotating table on my T&C grinder so it is within the proverbial gnat’s crotchet of perpendicular. Then I put a removable dowel pin in at that position to be able to restore it if the table was moved. I would personally avoid using the angle offset method as that gives a non-planar ground surface.

David

 

Can someone please tell me how to post with quotes but in such a way that my reply is not shown as a quote; I’ve tried everything I can think of.

Edited By David Littlewood on 17/01/2012 16:00:12

[Harold Hall 1Participant @haroldhall1]

The following is from the Union tool and cutter grinder operators manual

“In tool and cutter grinding the most frequently used wheel is the Cup Wheel. It is advisable to dress this wheel with an angle on the face thus presenting a single edge of the wheel to do the work and avoiding an excessive amount of wheel in contact with the cutter which could result in excessive heat and distortion taking place”

As can be seen from the above, it advises against an excessive amount of wheel being in contact with the with the cutter, this being the reason why I advocate a tool approaching at a very small angle as this guarantees that that situation will not occur.

It is interesting that this manual, and the Boxford one mentioned by Clive, both suggest dressing the cup wheels face to give a 5 to 15 degrees slope, making it therefore essentially concave. This of course avoiding the need to use the 1 degree approach angle as it essentially achieves the same result, that is, keeping the ground tool away from the wheels face.

Personally, if I had a T and C G I would limit the angle to say 1 to 2 degrees as with such a large angle the the edge must be quite week and quickly ware.

Readers who challenge my 1 degree angle should be aware that most who use my grinding rests will be working with the shops general purpose off hand grinder and dressing a small angle onto the side of the wheel would not be appropriate because of its use for other tasks. I worked that way for quite a while until I modified an off hand grinder to take cup and saucer wheels purely for tool sharpening.

Anyone who would like to read the Union Operators manual should go to the following web site. When there, click on downloads and then click on the picture of a T & C Grinder part way down on the right hand side. Incidentally, there are some pages from MEW also available on the site.

http://www.rulezman.com/rulezman_workshop_2/

I am surprised David of you concern regarding the concave nature of the face being ground with a 1 degree approach angle. I have calculated (to be precise I drew it out on my CAD package and that gave me the value) the depth of the curve on a 10mm wide lathe tool, with an approach angle of 1 degree and a 100mm diameter grinding wheel. The value is just 0.0043747mm.

My suggestions for sharpening workshop tooling, both in my books and on my website, are really aimed at the majority of workshop owners who are reliant on an off hand grinder. Those who are fortunate enough to own a commercial machine I would expect to use the machines manual.

Harold

[David LittlewoodParticipant @davidlittlewood51847]

Harold,

 

On reflection I think you are quite right – I simply had not given it that amount of thought, the actual concavity must be tiny. Also, you have set out a convincing reason for doing it, I don’t remember seeing that before but it seems quite logical. I must admit for the 0.05mm cuts I take it probably isn’t a big issue, but I will give it a try and see if it cuts cooler. Thanks for taking the trouble to set out the case.

 

David

[Tony Pratt 1Participant @tonypratt1]

From experience it is the accepted practice to have a ‘concave’ relief on cup wheels to limit the wheel surface area in contact with the job, this does in reality give a better finish and less prone to chatter. I would say 1-2 degrees is fine.

Tony

[robjon44Participant @robjon44]

Gentlemen, I have done a great deal of tool grinding,here is my fourpennorth, when I was given the task of grinding tools for 250 men, most of them turners, there were large green & grey pedestal grinders with recessed face wheels about the size of grindstones in a windmill for roughing out, 2 Herbert Junior surface grinders, one with green or grey wheels for special shapes such as the v-grooves in roller box tools, & the other a 3mm wide diamond disc for slitting purposes & servicing the tungsten carbide blocks Mr. Sandvik made with flat top & chip breaker for copying lathes, remarkably like the tools sold by Eccentric Engineering, also a diamond lapper for giving the finishing touches to brazed tip tc lathe tools. So, as I understand it, the natural lubricant of diamond is water, used that on the lapping wheel, precision guided by a matchstick stuck up the coolant pipe, purely to damp down the hardmetal particles, on the big grinders flood coolant because one was trying to salvage the damage inflicted on tools by gorillas with broken noses. When a green grit wheel reached the end of its life, lay on metal block, break up with hammer, put pieces in box on shelf for that purpose, knock lead bush from middle flat, put in box next to first box, to contribute to the making of lead hammers ( politically incorrect in these modern times ). When diamond wheels need a dose of looking at, take piece of green grit from box 1, use to remove gunge from wheel, no coolant then dip it in water. These diamond wheels lasted for a long tIme under the most arduous industrial conditions so I imagine any one of them would last a lifetime in a "shed dwellers workshop", like mine for example, & yes they have done robjon 44

[Martin Walsh 1Participant @martinwalsh1]

I'm probably telling people on here how to suck eggs

but always treat grinding wheels with the utmost of respect

always do a ring test before installing them and don't over tighten them

and make sure they run at the correct speed

I say this because many years ago when I was an apprentice in a toolroom

I saw a grinding wheel explode {nothing to do with me} resulting in the bits embedding themselves

in a wall

Best Wishes Martin

[colin hawesParticipant @colinhawes85982]

In my many years of grinding drills and other tools on the side of the wheel at home and in industry I have never seen any problem. My toolmaking days often required surface grinding of jigs and fixtures using both the side and the periphery of the wheel and it is often necessary to use the side of a wheel when offhand grinding to obtain the desired result especially with drills. In some instances I have found it safer to use the side to prevent grabbing. As always, use common sense. A wheel is most likely to burst if it is cracked or massively unbalanced. Colin

[Rick Kirkland 1Participant @rickkirkland1]

Care is the key. It's 44 years since the last time I saw a wheel burst. Even now it seems like yesterday. This was on a tool grinder which was not fitted with any kind of wheel guard. Aaaaaargh!!!!

Rick

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