Tool and cutter grinders, - a new slant

[John Stevenson]

OK the dogs got the bone and it's not letting go

Some thing I have been thinking about for a while, even got some bits but as I have more pressing matters I'll put this forward in case anyone else want's to run with it.

Take a say 6" wheel and present a tool directly to it horizontally and you get a flat face [ well nearly as there is a 3" radius to take into account.
Now do the same but say 1/2" above centre and you will get an angle of about 10 degrees. Many T&C grinder use this method to get clearance angles, some tilt the head and some raise or lower the wheel.
No right or wrong way just different ways to achieve the same thing.

Now take this horizontal head, fit a collet chuck to it and power it by a stepper driven indexer drive to get the 2,3, 4, divisions etc needed, that takes care of the indexing.
It also needs to be able to swivel at this point but can be manual.

The horizontal head needs to be on a ballscrew driven linear rail, again stepper driven and the wheel head needs to be able to move up and down, again by stepper.

Operation for a drill:
Spin the head to 135 degrees or what ever, fit drill to collet, line cutting edge up horizontal and present to the wheel, [ not running ] , on centre line.
Zero controller, back off say 0.200" and enter the drill program for that size from a library.
Wheel starts, head drops and presents drill to the wheel and grinds one secondary angle, backs off, raises head, feeds in drill to form primary angle, backs off rotates the collet 180 degrees and repeats.
Job done.

End mills can he handles in roughly the same manner.

Asbestos suit on, let the flames commence...............................

.

[Timleech]

It would be tempting to have a go along those lines, just as a project, but I too have enough on already. If I had the space to keep it, putting steppers and a CNC workhead on my Ward grinder would be a good excercise, & I've got another idea for getting motorised feed onto the head. I *definitely* don't have room, though, it has to go.
Maybe once I've got the shop somewhere near sorted, some sort of semi-CNC control on the Cinci grinder might be worth a try, just a workhead and rise & fall on the wheelhead. I've got some of the bits to do it.
Trouble is, my Bridgeport control has been in bits for months as the day job has got in the way, and there have been quite a few times when I really could have done with it
Shame about having to feed the family, there would be much more time for projects otherwise!

Tim

[Millman]

Don't know, John, if I'd trust the steppers to index that precisely. I've heard good and bad things about them, but never actually built anything with them. Maybe I'm just too used to mechanical indexing with positive stops. Hey, did I ever tell you how I hate CNCs? I thought so.

[Timleech]

Don't know, John, if I'd trust the steppers to index that precisely. I've heard good and bad things about them, but never actually built anything with them. Maybe I'm just too used to mechanical indexing with positive stops. Hey, did I ever tell you how I hate CNCs? I thought so.

Good enough for me. see

http://web.onetel.com/~duttondock/In...eelgear-5b.jpg

188 teeth using a stepper-driven rotary table. The flywheel is about 150Kg.
Cutting a '189th tooth' as a check didn't remove a whisker.

Tim

[Millman]

OK, I would be impressed with that set-up.

[JCHannum]

I see three problems,
1. How do you do the flutes?
2. The drill will have to turn as it is ground back to keep the lip horizontal due to the twist.
3. The nearest library is six miles away.

I was at an auction yesterday, a B&S T&C grinder sold for $75.00 & a Cincinatti for $50.00. Both were in operating condition if a bit shabby. I can't handle the large machines myself, but a couple of people got good deals. No grinder people were there.

[Timleech]

I was at an auction yesterday, a B&S T&C grinder sold for $75.00 & a Cincinatti for $50.00. Both were in operating condition if a bit shabby. I can't handle the large machines myself, but a couple of people got good deals. No grinder people were there.

Grinders can be bought cheaply enough, but as John said the other day you need a ton of tooling to go with them. That's where some sort of CNC head might score, may be able to take the place of a number of special items. If you wanted to take it a step further by including table movement in the control system, then you could even do spiral flutes without the need for fingers or fancy controlled spiral heads.

Tim

[Norman Atkinson]

I tend to echo the comments of Jim H who saw T&C's going very cheaply on his side of the Pond. My Clarkson Mk1 came in at £100 and although as rough as a badger's bum had a couple of holders. True, it cost the sensible dumping of abrasive wheels for safety but it cost about another £200 for more tooling which included a very expensive radius turning attacchment and a contraption to do reamers.
I didn't need to buy the additional accessories- but what the Hell?

On the other side of the argument is a kit to home build a Stent for £314 plus 17.5% Tax and carriage. Again, the Quorn is much the same and so is the Kennet and there are more but all need considerable time to build- and some complex tooling. The Clarkson was running after summoniing enough strength to lift the bastard out of my little car and stagger to a bit of space in my tiny shed.

You do get your balls chewed for flaming those who have not finished their own machines. Hey, Ho!

Nevertheless, John's ideas do approach a system which is approachable.

My problem is that I am too thick to understand stepper motors to indez the work. I count
One -Two
One two three
One, Two Three Four

And the designer of the Quorn used 5 washers in his lab coat to do 360 degrees.

We are getting there. Thank you John- Oh and congratulations on your new
award for services rented- rendered!

Norman
from the bar of the Goat and Compasses

One two

[John Stevenson]

I see three problems,
1. How do you do the flutes?
2. The drill will have to turn as it is ground back to keep the lip horizontal due to the twist.
3. The nearest library is six miles away.

I was at an auction yesterday, a B&S T&C grinder sold for $75.00 & a Cincinatti for $50.00. Both were in operating condition if a bit shabby. I can't handle the large machines myself, but a couple of people got good deals. No grinder people were there.

JC,
Just a concept idea.
[1] Flutes can be done by moving the head forward along the side of the wheel whilst rotating.
I didn't want to bring this into the equation at the moment due to complexity and confusing the natives, Norman stop scratch your nose, it's big enough

Have you noticed on newer end mills that they have the lead angle already etched on ?

Personally I'm not too interested in doing flutes as once you do the flute you then have special offsets just for that cutter to compensate for the amount you have removed.

[2] True if you have to remove shed loads, touching up will work on the one setting just like a drill grinder.
If the drill is that bad then hand grind back to a good point and start at that point.

[3] Move closer to the library.

T&C grinding is very dear to people hence the number of designs out there and the following it attracts on these forums,
It won't suit many but will also appeal to many others as the answer they have been looking for or as Tim siad an attachment for an existing T&C grinder.

I have a nice all singing, all dancing grinder but to do the odd cutter it's a pig to setup as regards time.
Unless I have a load of all the same cutters I can't afford to switch it on, it's cheaper to buy new or even pay to have it sharpened.

The local T&C guys to me have these 5 and 6 axis grinders that once the cutter is in the collet it does the whole thing automatically then spits it out.
A 20mm 3 or 4 flute cutter is in the machine for less than a minute for an end grind, two or three for a end and flute and it spits out the new diameter so you can reset the offsets.

Seeing these in action prompted me to think of a DIY CNC grinder.

.

[Millman]

[[once the cutter is in the collet it does the whole thing automatically then spits it out.]] Kinda' makes you sick, doesn't it?