Need help selecting a cutter grinder.

[implmex]

Good morning Superbowl:
You make a good and sensible point that is valid as soon as you start calculating costs and prioritizing them.

But Just a Sparky is pursuing a hobby.
That means he gets to enjoy himself without counting the cost in the same way you must when it's a business.
I have followed a very similar path he plans to, but my goal was to make what I cannot easily buy rather than hoping to save money.
Surprisingly, it has been profitable for me too, although I never really had any expectation it would be...at least not directly.

As I remarked in another thread, ( https://www.practicalmachinist.com/forum/threads/buy-vs-build-how-do-you-choose.410713/#post-4037210 ) I grew up in an era where every machinist worth his pay had to be able to grind cutters...there were no boxes of carbide inserts you could just swap out and if you needed a form cutter you had to find a way to make it.
There was no CNC to help you... everything had to be figured out in a completely different way compared to now.
If you needed a specific radius in the corner of a mold cavity, you had to modify an endmill to get that radius, so flute grinding was common for mold makers in the 1970's, and almost every toolroom had the capability

I have capitalized on that experience, and in my world, (prototyping and miniature machining) that skill has remained relevant, so I contend that if he learns it too, he will be able to do more with less investment, and pull feats of machining out of his hat that others can't easily duplicate.

So even if you cannot justify his proposal on purely economic terms, it's still a useful and worthwhile capability to pursue.
True, I don't flute grind endmills anymore either, and for exactly the same reason you articulated, but I do still grind a fair number of cutters and the skills I learned grinding endmills are not wasted.
Besides, it's kinda fun for me to make a cutter and have it work like I want it to.
It's also reassuring that I can keep my operation running without having to wait for cutters and plan the logistics of my jobs.
I hate logistics...I do it because I must, but whenever I can circumvent the need, I'm all in for the circumventing.

I don't know how much I've saved over the decades, but when I had a business partner, he used to routinely order 3 specials "just in case" and wait a week.
I often had my job done before he even got the cutters for his job, and I could make money on jobs he would lose his ass on.
He just closed his doors for good...couldn't make enough money to justify keeping it going.

He was trained a decade after I was, and he was (and remains) very very good at his trade, but I can still do shit he can't, and it's because I grew into the trade before he did, and learned self sufficiency he never had to.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[eKretz]

I like the idea of adapting a compact surface grinder. Would be nice to have one anyways for other things as mentioned, like cylindrical and... well, surface grinding. Truthfully my sticking point was that I had no idea any existed which are small enough (and self-contained enough) to be removed from their stand and placed on a different surface. My only exposure up until now has been the great big 36"+ clapped-out behemoths which tool and die shops out here regularly put out to pasture for dirt.

Do you have any recommendations for specific fixtures (makes/models) to adapt a surface grinder to the task of tool and cutter grinding? Features to look for aside from air bearings, indexing and collet compatibility? I might be able to elbow somebody to borrow the use of their surface grinder once in a while. Starting out with a couple of fixtures would allow me to get my proverbial feet wet on the (relatively) cheap and figure out what I do and don't like/want/need in a grinder when scouting for my own.

Something like a Harig Air-Flo maybe?

EDIT: Also seeing a Weldon model 'S' relief grinding fixture complete with cams and 'ER' style collets available... wondering if that would serve dual-purposes for both drill relief and endmill flute grinding. Can't find info on it... looks like it has a plain bearing spindle.

If you can find one, Royal Oak made some excellent relief grinding fixtures. An Air-Flo is decent for flute grinding on a surface grinder. Also a Grind-All is pretty handy. And Harig made a nice powered cylindrical grinding fixture too.

 

[implmex]

Hi again Just a Sparky:
My stuff is all home made, (with the exception of the air spindle) because the commercial stuff is all too big for my little grinder.
Here's a miniature version of a Harig Grind All:


Here's a swiveling tilting setup I use to grind things like miniature carbide reamers and miniature threading bars;


Here's my cylindrical grinding setup for necking cutters and making things like miniature saws:


In addition I have these:







I also have a wire and a sinker EDM that get used for this purpose among other things.
This is a pretty comprehensive set of goodies...only the first three are relevant to your needs for tricking out a Sanford.
They're not difficult to make.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[gbent]

I don't have near the experience of carbidebob, Michigan buck, implmex, or ekretz, but I have ground a couple of tools.

My most versatile, small footprint set up choice would be a surface grinder. Surface grinders are useful for any machine shop. Then I would get either a harig or weldon air spindle to do end mill flutes. Weldon also had a end sharpening fixture that mounted on top of the air bar, but it wasn't impressive. I would get a harig whirleygig (or newbould) for ends and all sorts of other cylindrical grinding.

I would get a weldon model S to do drill points up to 11/16. I would do larger drills in a vee block.

 

[implmex]

Hi gbent:
Yeah, that's where the OP seems to be going.
His biggest concern is that he has almost no space for a new toy, so it's gotta be a really small one he can mount on wheels and roll around, or set up on a bench.
Full sized machines are out.
Sadly that narrows the field a lot.
So if he scores a baby Sanford and tries to put a standard 5C air spindle on it, that's kinda like parking an elephant on a bicycle.
Similarly a Harig #1 Grindall is awfully big for the Sanford.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[Just a Sparky]

Can the Weldon 'S' also sharpen endmill flutes by disengaging the gear drive & cam and fitting a stylus? Or does it's plain bearing suffer from the usual stick-slip that is characteristic of plain bearings?

If I could satisfactorily use a Weldon 'S' to do both drill points and endmill flutes, that would make it a great one-stop starter kit for me. An ordinary spindex with good concentricity would then get me started with endmill teeth.

In regards to the elephant on a bicycle situation, would building a simple cantilever fixture plate for mounting accessories on a compact grinder not be a viable solution? mount the fixture plate to the table T-slots, then put the mag chuck on the fixture plate to offset it? More or less turning it into a glorified Cuttermaster with the addition of Z-axis travel at that point. It's not like I'd have to worry about heavy tool pressures like with a milling machine, so a good piece of 1" to 1-1/2" thick cold-rolled rectangle should provide adequate rigidity if I center the mag chuck above the edge of the grinder table. And it's a surface grinder, so getting the plate parallel should be dead easy.

 

[eKretz]

Doing all that I might be concerned with rigidity. So I'm going to answer your question "maybe."

 

[implmex]

Hi Just a Sparky:
You have to remember just how small these baby Sanfords are.
My GOTO solution would be to get an ER 20 straight shank collet extension chuck with a 1" shank.
Command makes a nice one, that's 6" long with an ultra compact, round collet nut with slots around the periphery for a wrench.
Lap it until it's perfect and make a 3" long Durabar housing for it so you can put air to it.
The housing needs to be a simple rectangular block with a hole in it plumbed for shop air...no swiveling, tilting bullshit with graduations.
If you want to get fancy, put a retract mechanism on it so you can back the cutter away from the wheel once you've ground a flute.
Most just use a pivot and a big spring to hold the fixture against a stop.

Voila...you have a flute grinding fixture that is a more suitable size for your Sanford.
You can grind a 1/2" cutter with it, and that's the biggest I ever run anyway, so it should be fine for your needs too.

Build yourself a nice compact spin fixture while you're at it...they're not difficult to make and they are super handy to have around for milling too.
Make a swiveling tilting fixture as well and you're all set for just about any task.
None of it will be as efficient as dedicated machines, but it'll still be fully capable.

If you try to hang a 1" mild steel plate and a Harig #1 on the Sanford, you'll probably tip it over.
Ditto if you try to mount a 5C air spindle to it.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[gbent]

I've never used a Sanford, don't know I've even seen one. I must defer to Marcus' opinion on this machine.

Any surface grinder with a whirlygig needs a fixture plate to mount the whirlygig to the operator side of the magnet. Otherwise you have nearly zero room in front of the whirlygig for working. As to the Model S, no, it won't do end mills. Even if you figured out how to make it do end mills, after the second cutter you would hate both yourself and the Model S. It makes very good drill points, but is not a quick change for different diameters.

 

[Superbowl]

I have always wondered why there is not a small cnc cutter grinder available where sharpening could be automatic. Seems like a no brainer for drill bits where the size is always known. Also it seems like you could have a small grinder mounted as a live tool in a cnc lathe and use it to sharpen end mills, drill bits, etc.

 

[EmanuelGoldstein]

I have always wondered why there is not a small cnc cutter grinder available where sharpening could be automatic.

There are at least three brands that I can think of.

OP's problem is that he has no space.

 

[CarbideBob]

There are at least three brands that I can think of.

OP's problem is that he has no space.

And these three brands and machines with reasonable price tags are????

 

[BOB-OO]

There are at least three brands that I can think of.

OP's problem is that he has no space.

Please share, I have space for one if its reasonably priced.

 

[CarbideBob]

Please share, I have space for one if its reasonably priced.

I think you may be in for sticker shock on what "reasonable" price on these toys are.
New 1/2 million or more. 10 cents on the dollar well used and you are at only $50,000..
My 6 axis 6 spindle Ewamatic was $600,000+ in mid 1990 money. We bought the first one in the USA. Told dad he was crazy and off the deep end.
Sometimes machines in this class down to only 10 or 20k but those have problems. I am talking full cnc.

 

[EmanuelGoldstein]

Ah, now you guys want them cheap, too ! That wasn't part of the requirements before

There's some China ones which I won't even mention, but even in the US I've seen used Walters for cheap. Ten grandish, but they had "old" controls, ooooh. I've seen Ancas and Stars for cheap, too. But if you want cheap you're going to have to do some work on them.

(10k will buy you a cup of starbucks coffee and maybe a cinamon roll these days. Money is nothing anymore.)

If you'd really buy a china one I'd go look ... fact is, you'd be shocked at what China is making now. I had seen improvements at the last couple shows but over the virus period ? There's some pretty nice-looking stuff today. Haas is finished in this country, they have better cheaper local machines now. Mazak is next on the target bale

 

[Garwood]

I've made a dozen or so special lathe and mill cutters and necked endmills on surface grinders. I have an SRD drill grinder for small drills and the belt grinder takes care of the big ones. I've never sharpened an endmill. Never actually needed to that I can think of.

Maybe I'm totally missing out not owning T&C grinder, but I don't think I'd need any capabilities they have that a SG doesn't.

I feel like if I had the skills to make any tool I need like Marcus, I'd have to have one in my arsenal otherwise my problem solving skills would be compromised. As I don't have those advanced tool grinding skills I will approach things differently.


Imo, with having a decent shop with a lot of capabilities, having bought, setup and learned literally hundreds of tons of machines- If you have decided you want to immerse yourself in tool grinding and actually want to say " Yeah, I can grind that" don't fuck around with junk and don't use limited space as an excuse. Make the room, man up and buy the best real machine you can afford.

 

[EmanuelGoldstein]

.... don't fuck around with junk and don't use limited space as an excuse. Make the room, man up and buy the best real machine you can afford.

I think he just wants to play at it for fun, and maybe a little convenience. Probably most of us have done that a few times (insert guilty look here). Life's not always about the money, yes ?

 

[implmex]

Hi Superbowl:
You raise an interesting thought experiment.
In fact, there is at least one tool grinding house that re-purposed a conventional CNC machine to do exactly that.

The shop is AB Tools in California and the machine that was pressed into service was a Haas with a trunnion on it to make it a poor boy's 5 axis grinder.
He used it to grind custom cutters and may even still have it now that he has Ancas to do the bulk of his grinding.

It takes a lot of screwing around to make it work, and it's very slow compared to a "real" grinder, but for customs it works just fine.

If you're bloody minded enough to put in all of what it takes, you could do it too.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[CarbideBob]

It takes a lot of screwing around to make it work, and it's very slow compared to a "real" grinder, but for customs it works just fine.

I would not say it slower, just maybe harder to program.
Try grinding the many type of dill points with this arrangement.
The real secret in the sauce of 5 and 6 axis tool grinders is the top level software that comes with them.
(stories are that Walters and Anca share something common on this end)
Other differences are minimum command moves, that tool changer is not micron level and the 4th and 5th gets in the way of many things.
My first try at something like this was an Ikegai TV4 with a Troyke 4 and 5th added on. (mid 80s)

 

[CarbideBob]

There are at least three brands that I can think of.

OP's problem is that he has no space.

Superbowl asked for small. That a reasonable request. Like desktop or workbench size. Not some 8000-10,000 pound thing.
Options under one ton as that would be a lot for my workbench to hold.
I have seen it done down at 3000-4000 and a smaller bit of floor space but these companies have died.
I considered trying this machine building market so many times. The math just does not add up no matter how hard I try.
Did the flat tool and IC grinding machine build side try. That killed me....almost literally.