Kennet Tool and Cutter grinder

[Fergus OMore]

As I informed Nick, I don't use my endmill/slot drill holder but use a rather odd combination of a set of ER25 collets which fix onto a Vertex BSO dividing head which will tilt progressively to be a rotary table but on my Clarkson Mark 1 grinder. Well, that's my take on things.

In Nick's case, I would probably either use the existing tool holder from the Kennet and use the lathe tool holder to hold a bored out bit of metal to hold and assortment of adapters ie 1/2", 3/8" and so on.  Other wise, I'd use a bit of plate and bolt a bit of square to sit on top of it.

You see he's got a rather fine protractor on one of the tables and a smaller protractor to adjust the tilt of the working tables.

It's doing well. I only wish that I could get my camera to work as well-------booo, hiss

Norman

[MadNick]

In Nick's case, I would probably either use the existing tool holder from the Kennet and use the lathe tool holder to hold a bored out bit of metal to hold and assortment of adapters ie 1/2", 3/8" and so on.  Other wise, I'd use a bit of plate and bolt a bit of square to sit on top of it.
Norman

I like it a lot and will take the path of least resistance every time

Nick

[Fergus OMore]

What is being sparked off is a wider interest not just on the Kennet with Nick but Quorns and other grinders.

It does prompt me to add a comment to others that tooling for one machine can often be swopped onto another- and it is sometimes an improvement.

And 'my camera' simply refuses to listen to me swearing at it.


And anyone know why one of my hearing aids- isn't.  Pardon, speak up!

Can't win 'em all!

[MadNick]

Can't win 'em all!

Where would you put them?

After our emails this afternoon I am back to the Workshop Practice Series, number 35 and reading up on the endmill sharpening fixture to see what can be pilfered.

I need to get the end mill attachment working as soon as poss as making the damn thing has blunted them all!

nick

[Fergus OMore]

Hi Nick,
  Really you should be on Miners and my E-mail exchange of info. Heady stuff but all that you have to do is to follow the words and the music about holding slot drills and carefully grinding first and secondary clearance angles at 90 or 180 degrees to each other.

What you have got to now will do the ends of your drills.- or enough to not ask  the  Madmodders' rat to gnaw at yer bit of metal. There's one about- it feeds on emery cloth

Better go- not listening. Me 'gugger lugs' are on the blink or gummed up or summat equally nasty and I'm in a bit of a moody.

[MadNick]

Thanks Norman,

I managed a few hours today.

First of all I welded the table support onto the base after carefully winding the table up against the spindle to get it square. Then I farted about with the clamp handles as two of them needed swapping over and one was way too long and either banged into the table at (12 o'clock) or the worktop (at 6 o'clock).

Well here it is assembled so far -



But theres still loads to do.I really need to address the main clamping assembly as the larger thread (to adjust tilt) has been cut crooked. Also the indicator for the angle of tilt is not dialled in properly and rocks around. I asked my neighbour to cut off a nice piece of wood and plane it down for a base, then I can start thinking about fitting the motor.

Another gratutitous picture -



Not my paintjob!

Nick

[DaveH]

Nick.

You are doing a good job there  coming a long nicely

Looks like one of my paint jobs  whots rong withit 
 
DaveH

[Rob.Wilson]

Lookin good Nick 


Rob

[doubleboost]

Hi
Nick
If you need any blunt end mills just ask
Looking great
John

[MadNick]

Evening,

A quick update. I needed to make a big nob to lock down the tool holders. Luckily I had a piece of knurled ali which was approximately the right dimensions but was drilled out slightly larger than the thread I needed. In the end I made a core for it from steel and knocked it in with a hammer. It was then drilled and threaded -



Fitted -



You can see the intended base for the tool. My neighbour made a terrific job of planing down and then staining a nice piece of driftwood - he reckons its some kind of hard wood from South Africa.

Coming together...

Nick

[MadNick]

Afternoon,

The next task was to clean up the slot in the tool holder as, after measuring, it was clear the slot wasnt parallel to the base. This would certainly have added error to any angles that need to be ground.

Last night I clamped everything up in the mill, not really preferred practice but there wasnt a lot of room -



Does that get you wet?! It took me an hour or so to set things up, checking for deflection in x, y and z and left any machining until this afternoon -



I machined the slot out and measured up - all good. Then the plan was to use a bit of brass as a point for the holder. I came up with this -



Thats it for the moment. Im making a start on an attachment to grind end mills.

Nick

[Fergus OMore]

Always remember that the lips of end mills and slot drills are ground almost parallel to the grinding wheel- giving 'a toe in' of not more than a couple of degrees. So you don't need the protractor ring. What you do need is the ability to hold the halves or quarters and the ability to get the first and secondary clearances but having stops to avoid crossing over too far. The last is an error which will destroy your end mill.

That is why I prattled on to you about  a different holder. Of course, you can do it but take heed of just how careful one needs to be.


Cheers

Norman

[MadNick]

Norman.

Good to hear from you

Im still considering a design for the end mill holder and need to do more research.

Until then im going to get the thing fitted to its base and running so I can practice on some lathe bits and one for the fly cutter.

Nick

[Fergus OMore]

Yes, you are following a well trodden path to gain experience. Once you are familiar with doing square lathe tools, you move on to working in 'the round' with lathe tools and then you begin to have to think about your maths and angles and things.

Sadly, few of us progress into such rarified stuff. However, there are bits of useful guidance. Chaddock in his Quorn book gives lots of guidance and so does Thomas especially in his Model Engineers Workshop Manual. What you are going to find is that the two Kennet tool holders will do it all but it does require  a lot of head scratching to get angles right. At this point, I would suggest that you gain experience with them and them move on to more complicated tool holders later.

It is not going to dawn on you- just like that but it will come as you progress.

Cheers

N

[MadNick]

Thanks Norman.

Would you be able to advise as to the diameter of the pulleys for my abominable 1/4hp motor please?

Getting closer, I fitted the grinder to the base today, just need to figure out the best way for the motor to sit.

nick

[Fergus OMore]

Hi Nick- still computer problems

OK- and now to the pulleys!

Here I strongly disagree with the plans
The plans say 5. 3/16th and 2. 5/8th for the pulleys which is fine for the small wheels supplied by Model Engineering Services for both the Quorn and the Kennet but there will be times when your machine should have a larger wheel to rough grind. In consequence,
you should think in terms of a double pulley at both the grinder and the motor.

If you think about it carefully, your lathe has variable speeds. Your Kennet is only different in that your lathe moves metal with a tool whereas your Kennet uses grit. All that you have to ensure is that you don't exceed the recommended( safe) speeds for the abrasive wheels.

Sounds pretty heady stuff? Well, I did say that you are moving into an aspect of model engineering where you leave  most people are either unable or unwilling to make their own cutting tools. Well, I hinted at it.

Cheers

N

[MadNick]

Thanks Norman,

Anything I can do to help or is it still under 'the curse'? lol

So those are two pulley sizes recommended for use with two types of grinding wheel on the 1/4HP motor, is that right?

Nick.

[Fergus OMore]

I'm assuming that you want to go no faster than 7000rpm for a small wheel so if you had a 2880 rpm motor- which you haven't, you would use the 2 to 1 pulleys( per drawings and my earlier post) to give something like a safe 4000 revs. However, you want roughly double  the motor pulley diameter for the dreaded 1440 one. however, I assume that if you want a bigger wheel the present pulleys  would be OK.

If you think about it, a cheap but not too nasty 6" Double ended grinder ( full of Eastern promise) will drive a 6" wheel at each end at 2880 rpm.

So, if you recall my earlier reservations, I would have gone out and got one- until something better materialised.

   If you had one, you could rough grind at one end-- and drive the Kennet from the other. :

I might not be the World's best computer freak( said he waving his wooden leg aloft) but  I 've done this tool and cutter malarkey before

Goes back to his wheelchair and incontinence pads

Norm

[MadNick]

Hello,

Well its been a busy afternoon.

I started off by farting around with a newly purchased Clarke DE grinder to do away with the pulleys and spindle and go direct against the cup wheel that I purchased. Mid morning I nipped round to a mates who told me he had found a sweet little Emerson motor - 1450RPM and 1/10 HP -



Well that started off some frenzied calculations on safe wheel speed and what I could manage with my limited pulley choice. After further farting around I found a pulley which came from my old MK2 Golf. I quickly made up a boss for it to go on the Emerson -



My calculations tell me with the drive speed of 1450RPM and diameter of 82mm will achieve a driven speed of 4100RPM on a diameter of 29mm. The grinding wheels have a safe speed of 4500RPMs. Hopefully this will be enough to get me started, just enough so I can make the tool profile I need to make a slightly larger driver diameter.

Loosely assembled -



Next will be to fit the Emerson to the base and wire in some electrics.

Nick

[Fergus OMore]

Hi Nick,

           You are almost in a position to -- See The Wheels Go Around.

Leave altering pulleys - and get some tools that will make life easier.

That- in case you've forgotten- is where you came in.

Cheers

N

[MadNick]

Afternoon,

Well I fitted the motor and got the wheels turning around I even managed to do a couple of test cuts on some HSS but there is, however, a problem.

All along this build I have discovered crooked and mixed threads, off-centre holes, badly fitting parts - its been a nightmare. I assume the two missing components are the best bits because everything else has been, er accuracy challenged.

I have now found out the spindle is running off-centre which makes the cup grinding wheel run off-balance and with a buckle in it. I could do away with the spindle and revert to the direct method against the Clarkey but I reckon it would take as long to make a new spindle as it would to make the pedastal required to get the Clarkey to the right height.

I need to do something but just havent decided what as yet...

Nick

[Fergus OMore]

You have a reasonably true spindle in the Clarke. Making a pedestal is only a matter of building up squares of chip board and holding it down with a few long bolts from Wilkinsons!

Once you are making sharp tools, you can concentrate on either re-screwing or re-tapping or making new bits.

I suspect that a tiny sliver removed from some so called mating surfaces will work wonders.
Much of warped stuff is the inability to work accurately up to a shoulder. A removed whisker often transform what looks like a  'Thrupple Nut'

Attention to detail


N

[MadNick]

Morning,

Quick update. Have fitted the Clarke just to get things going. I was spending too much time on the other spindle - 



There is still a kick in the grinding face, however. I checked with the other wheel on both ends of the grinder - same issue, will have to manage with it for the meantime.

Amid a fanfare of golden bugles, flags and dusky maidens, I started making my inaugural tool yesterday. You know I mentioned the project had been bedevilled by a curse, well the curse has struck again - the pivot for the toolholder pulled clean out!

Ive had enough for the time being and need to make some progress with the chopper instead.

Nick

[Fergus OMore]

Enter the 7th Cavalry or whoever to rescue Custard   

One- I've suggested that his wheel needs dressing( leave the dusky maidens to be viewed)
Suggested that he  bought a diamond dresser( not you Moma, sit down) but No, NO

So Ive told him to use a scrap carbide bit or lathe tool. Could be a crap carbide masonry drill.

Finish off with a bit of crap wheel.

As for the 'pulling out' well it's Titanic time and yet again-- rotten rivets.

Need this deaf old fart say more ???????????????????????????????????????????????

[MadNick]

And this afternoon's efforts featured real achievement 

First I fixed the stripped thread. You can see the knackered thread in the above photo. Luckily the pivot was cut 1/4" or so too long so I simply cut a thread with a larger diameter on the shank for 1/4" or so, with a corresponding one to screw it into on the top table. I then Loctited it in place.

The grinding wheel was then dressed to get a nice flat, consistent surface and I set up the top table/tool holder parallel to it.

I then ground two 5 degree rake angles on a piece of HSS to make a start on the tool for my fly cutter. Of course there are a lot of small niggles to iron out but now im actually seeing some results there is more motivation to keep going. I certainly need to make some changes to the tilt angle indicator and clamp, fit rubber feet to the wooden base to stop it moving and fab up some kind of guard.

Very pleased - thank-you Norman.

Nick