Tool & Cutter grinder options…

[Another JohnSParticipant @anotherjohns]

Chris – I think you have lots of options here.

You have to decide on what you want, and what you want to do; I chose the Worden simply because it was the easiest way of getting down to sharpening the ends of end mills, drills (4-facet), and lathe tools.

I treated the building of the Worden just like I would treat making a machining jig – something required to proceed another step on my main projects.

What was NOT a goal – making a T&C grinder!

Another JohnS.

[Chris HeapyParticipant @chrisheapy71135]

I think I have a plan now. I will make a dovetail plate and attach a motorised spindle to the upper part of the mill's knee dovetail – here:

It can be quickly removed when not required. The mill table offers X-Y-Z movements, the swivelling slide offers fine adjustment of depth of cut, the quick indexer offers all that is required for multi-point indexing. I even have a spare 10" rotary table that can be pressed into use if I want better precision than that offered by the swivelling slide base.

All I need now is a compact grinding spindle of some sort. I note ARC are selling some 3-ph high-speed spindles with ER20 chucks, I was wondering if it would be safe to mount a diamond cup wheel to one of these? Failing that, I could buy a cheap bench grinder and mount just the required parts on my adapter plate.

[Alan HopwoodParticipant @alanhopwood63369]

Steve asked about the advantage of the Quorn spindle V the original Stent; as I see it the Quorn can easily be used either facing left or right in the mounting block, it also is a very well designed grinding spindle with laberinth (sp?) seal and a well controlled pre-loaded bearing assembly. Mind you, I'm one who is known to talk in tenths and work in sixteenths.

Alan.

[Sub MandrelParticipant @submandrel]

Has anyone tried fitting a grinding spindle to the head of a mill to produce a basic surface grinder?

Neil

[FMESParticipant @fmes]

I was given what I think is an almost finished Stent, but to be honest I havent got a clue how to use it

[Chris HeapyParticipant @chrisheapy71135]

Made a start on this. The dovetail doesn't need to be very accurate – it's more of a fixture than a sliding component – so rather than hew out a thick chunk of metal with a dovetail cutter I'm using bolt-on sheaves.

Cutting one of the two dovetail blocks on my angle vice:

These will be bolted to the plate, looking something like this:

[OuBallieParticipant @ouballie]

Stealth cutter Chris?

Is that shield standard or DIY and how is it mounted?

I'm enquiring, as I need to make similar for my machines.

Geoff – Early coffee

[Eddy SpriggsParticipant @eddyspriggs]

Lofty76,

If you google "Clarkson Cutter Grinder Manual" this will tell you all you need to know.

Hope this helps, Eddy.

[Chris HeapyParticipant @chrisheapy71135]

Posted by OuBallie on 18/05/2013 00:46:38:

Stealth cutter Chris?

Is that shield standard or DIY and how is it mounted?

I'm enquiring, as I need to make similar for my machines.

Geoff – Early coffee

Ha yes, machine was running under power feed there, 20mm slot drill, must be an odd flash effect.

The shield on the mill is the standard one supplied with the A2S – but it broke so I had to straighten the edge on the mill and re-attach to its bracket. It's about 2" less width than it was.

I also just bought an inexpensive shield for the lathe from ARC, one with a permanent magnetic base (which I replaced with an Eclipse switchable one). This is really only used when I turn brass which sprays needles everywhere! Perhaps one of those will do what you want?

[OuBallieParticipant @ouballie]

Thanks Chris.

I've been thinking of using magnets, but can see them being covered in swarf in no time.

Your solutions seem to be the best approach.

My local DIY emporium, that stocked clear Perspex, went belly up a month ago, and the new enterprise don't stock that. Every time I walked past the Perspex I always told myself to buy a sheet, but never did.

When oh when will I learn to heed myself!

Geoff – mal à la tête

[Chris HeapyParticipant @chrisheapy71135]

Completed step (1), I now have a bracket suitable for mounting a grinding spindle (of some sort). Although the bracket is adjustable/removable in actual fact it is not in the way of anything, I very rarely need the table to be lifted to the top of the knee dovetail so in all likelyhood it can just stay there. I could have saved myself some effort by just bolting it to the mill column. Oh well…

In a good position for the cutter holder…

The plate doesn't interfere with normal operations of the mill – though the grinding spindle and cup wheel would… So that at least needs to be removable.

[Chris HeapyParticipant @chrisheapy71135]

I've been struggling to find a suitable motor to use for this job, I thought it would be easy to pick up a ~300W single-phase motor at approx 3000rpm and suitable for flange mounting. Not so. In the end I decided to replace my old bench grinder and recycle the motor in that. Easier said than done! I needed to machine the boss on one end to accept a flange of some sort, and for that some serious disassembly was required – including splitting the motor. The rounded casings at each end also carry the bearings – which were seated with retaining compund – and the only way the casing could come apart was to pull the bearings. It was obvious this wasn't a procedure the manufacturers expected to be carried out. With considerable persistence, hitting with hammers and wedges of various kinds (and colourful language of course) the thing eventually came apart. The end casings were not very substantial (diecast mouldings) so I had to skim the minimum required to get the boss parallel. Holding it so the end casing ran true was another adventure. Anyway, did all that and re-assembled with new retaining compound and the motor still works (!). I'm turning up a flange now to attach it to the dovetail plate already fitted to the mill. Having seen how the motor is constructed I'm not too happy about suspending the motor by the casing alone so will need to think about how I can give it additional support. Thankfully it is much lighter now with the cast base removed and no grinding wheels etc., the switch gear I will re-locate to a small custom box somewhere.

Serious disassembly….

The turned boss ready to accept a mounting flange.

Edited By Chris Heapy on 21/05/2013 02:51:37

[Ian S CParticipant @iansc]

Could you not have just made a flat plate to bolt under the motor, with a right angled bit up one end, to act as the flange, bored to fit over the spiggot the the gaurd was mounted on.    Ian S C

Edited By Ian S C on 21/05/2013 13:26:09

[Chris HeapyParticipant @chrisheapy71135]

Posted by Ian S C on 21/05/2013 13:22:07:

Could you not have just made a flat plate to bolt under the motor, with a right angled bit up one end, to act as the flange, bored to fit over the spiggot the the gaurd was mounted on. Ian S C

Edited By Ian S C on 21/05/2013 13:26:09

It would have been possible perhaps Ian, and a welded steel angle bracket might have worked. There were quite a few options but the solution I went for is as compact as possible, and it's very stable – but far from the easiest to make… I hate doing things the easy way (joke).

.oOo.

So, with the motor and flange turned to size I next looked at the plate and how to mount them. By the way – I should have known better but… when I machined the flange I made it a very close fit on the turned part of the motor casing, I intended to use Loctite 638 as the main method of holding it in place. So I take the freshly machined flange off the lathe and test fit it on the motor. Of course, it was aluminium, and it was fairly warm, and the motor was cold… you can guess what happened next. Push the flange on and it cooled quickly giving me a nice shrink-fit. Bit of a pig to get it off again. Moral: cool it down first then test for fit.

Anyway, I wanted to bore a recess in the back of the plate for the flange, and 3 bolts through the plate into the flange to hold it in place. I scratch my head trying to figure out how to do this. My boring head doesn't have the capacity (and it's manual not automatic so many stops and starts would have been required to use it). The plate was quite long too – far to big to fit in the lathe. Eventually I thought of attaching it to my rotating table on the the mill bed, and because it is a Turret Mill I could pull the head forwards and that gave me just enough clearance for the thing to rotate fully. The recess could then be cut with an endmill.

Setup for machining the recess in the rear of the plate:

Turret head is pulled out almost to its fullest extent:

I spend the next hour being a human CNC miller, I sure wish I had a real CNC machine…

So there we are; motor is held very securely in place

I think I will change the cap-head 8mm bolts for some countersunk ones, then everything will be flush.

Now I need a diamond cup wheel and I'll need to make a protective shield. I also need a new bench grinder… I was looking for an excuse to upgrade to an 8" grinder anyway.

Edited By Chris Heapy on 21/05/2013 18:19:19

[BubbleParticipant @bubble]

Hi all

I don't usually raise Health & Safety, common sense should cover most things

However, safety shields near millers and grinders should be polycarbonate and about 6mm thick.

This is tough under impact and not inclined to fracture into shards at eye level.

Perspex is not good. Acrylic is better, but comes in several grades, I suspect the DIY stores stock will the lowest toughness stuff.

Jim

ps I built my Quorn ten years ago, ball handles and all, and am constantly amazed at its versatility.

[Ian PParticipant @ianp]

Jim

For the shields Polycarbonate is best as you say, but I thought Perspex was just a brand name for Acrylic?

Ian P

[Sub MandrelParticipant @submandrel]

Acrylic is worse than nothing. I made some acrylic guards and they crack if you look at them in a funny way.

Does anyone know a source of polycarbonate in offcut sizes suitable for making guards? A whole sheet costs an arm and a leg.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Thinks

Does it really need to be 6mm thick? … or would a "Double Glazed" version [i.e. two thin sheets, with an air-gap, in a frame] be as good? or maybe even better?

Thin Polycarbonate sheet is very readily available.

MichaelG.

[Chris HeapyParticipant @chrisheapy71135]

Depends what you're guarding against? An 8" grindstone bursting is not funny. However, with an aluminium/diamond cup wheel there isn't much chance of large pieces of shrapnel flying about, so a fairly thin plate of some sort is all that is needed (IMHO).

.oOo.

Rounding off the end of the plate:

The recess the flange fits into

Looks a bit better now with the bolts sunk into counterbores

[WindyParticipant @windy30762]

Hi Neil I have been getting polycarbonate from **LINK** he was at Harrogate ME show and goes to various autojumbles.

Let him know what you want and he might be able help.

Paul

 

Edited By Windy on 22/05/2013 13:50:00

[Chris HeapyParticipant @chrisheapy71135]

The shield/cover for the 4" cup wheel I propose to fit I will make from some brass tube I've had lying around for maybe 40 years… I think it was an old shell casing from WW1 (!) but it had the end cut off and was last used as a poker stand by my grandfather. I cut about 4" off using the bandsaw (actually, I said it was made of brass but I think it's a new alloy – called Brass Carbide, this stuff is HARD).

Chips come off as tiny bits leaving a very nice finish when using a tipped tool.

And this is how it will look, the I.D. is about 4.75" so enough clearnance for the wheel. I'll cut a notch the same width/depth as the rear plate then have one thumbscrew holding it in place. Note I screwed the base back on to the motor so I could muck about with the electrics – it's not a permanent solution.

[Chris CourtneyParticipant @chriscourtney72250]

I would echo what has been said about acylic, it isn't suitable for guards, it can shatter. Polycarbonate is widely available, I have bought it from **LINK**

Chris

[Tony Pratt 1Participant @tonypratt1]

Hi Chris H, I admire you ingenuity and don't want to rain on your parade but what is going to stop the grinding dust going into the internals of your milling machine and also the slides? I have a Stent T & C and the dust goes everywhere!

Tony

[Chris HeapyParticipant @chrisheapy71135]

Posted by Tony Pratt 1 on 22/05/2013 17:31:51:

Hi Chris H, I admire you ingenuity and don't want to rain on your parade but what is going to stop the grinding dust going into the internals of your milling machine and also the slides? I have a Stent T & C and the dust goes everywhere!

Tony

It's a fair point – there will be a vacuum pipe attached to that brass shield and I will protect the rest of the machine as best I can with plastic sheets when in use. I'm not using grit wheels which would shed copious abrasive grit everywhere (using a diamond cup wheel instead) and I would hate to use a dressing stone on a grit wheel near my machines – did that once on my bench grinder, never again! If I need to dress the grinding wheel I take the whole thing outside. Not a perfect solution I know but in a garage-sized workshop if you do ANY grinding in there with ordinary grit wheels then debris will find its way onto your machines. Regular cleaning and maintenance is the rule.

[Chris HeapyParticipant @chrisheapy71135]

Far more engineering went into making the cover than warrented – or expected, and it's still not quite finished. Still, we do this for enjoyment, right?

By way of good fortune I had some alloy tube that had exactly the correct dimensions (inside and outside) to allow me to make the cover a quick-release mounting. All I needed to do was cut a slice off, press it in place with a smear of 638, then mill out a section so it fits the back plate.

Thus:

It would have been quick and simple had that 'brass' tube not been such an absolute pain to machine. It would grab the cutter at the least provocation.

Anyway, the cover fits with a couple of thumbscrews and can be removed from the front in seconds.

Edited By Chris Heapy on 23/05/2013 09:10:39

Edited By Chris Heapy on 23/05/2013 09:20:40

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