Mini surface grinder

[bogstandard]

It doesn't have to be as complicated as this

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But the idea is there to make one similar.

A 40tpi leadscrew or an old micrometer head, a ball slide and a small DC motor, and it is nearly there.

Definitely an 'I could make that' project.


Bogs

[NorthOf40]

Nice find

I found the builders homepage HERE

[Brass_Machine]

Ya know... I wanted to build one. Posted about it on another site and was poo poo'd.

I think I will. I have plans for a small hobby shop one... May just have to go ahead and build it.

Eric

[bogstandard]

Eric,

Most of the stuff I grind on my full sized one would most probably be only a couple of square inches. So one like this would definitely be very useful.

A manual or small electric crank would give you the X axis continuous movement coupled to a ratchet to give auto Y movement, and you would be in business.

Bogs

[CrewCab]

A manual or small electric crank would give you the X axis continuous movement coupled to a ratchet to give auto Y movement, and you would be in business.

Steady on John, remember your dealing with someone more at home with bricks and mortar, structural steel and stud walling ............... where acceptable tolerances are +/- 10mm  ..............  but I think I get the general gist, putting it down on paper might be a different matter .........  anyway ..........

I agree that a small surface grinder, capable of dealing with small stock, would be really useful and I'd be interested in building one, though ...... as above ......... the design is beyond my capabilities ............. without a lot of research ............ ERIC .............. I feel a team design coming on here ....     ....... errrr  ..............  superviseed by Bogs of course   

CC

[spuddevans]

You know, I think this would be a great little addition to any workshop. I think this might just go on the "Projects" list 


Thanks for posting this, now if someone could post up some info on how to compress time so that I might have even the slightest chance of building a fraction of the things on my "Projects" list, I'd be eternally grateful 


Tim

[bogstandard]

I wouldn't mind helping out, but at the moment, I have six weeks to get six engines finished, and I DAREN'T be sidetracked.

John

[sorveltaja]

I wouldn't mind helping out, but at the moment, I have six weeks to get six engines finished, and I DAREN'T be sidetracked.
John

Six engines?? In six weeks? You must be.. maybe not an engine, but machine?

[bogstandard]

A bit  , but no, five of the engines use many common parts, so it is more of a production exercise, 15 cylinders etc.

You will see the start of the post sometime over the weekend.

Just getting all the bits together.

Bogs

[John Hill]

Please excuse the ignorance of this former sheep shearer from Dunnunder but just what are the basic principles and characteristics of a surface grinder?

If they are what I think they are I just might make one in an idle moment or two.

[bogstandard]

John,

If set up right, it will allow you to grind surfaces very flat, ie, no detectable surface deviations.

Also, because it grinds rather than cuts, you can harden a piece, then still be able to get perfect dimensions on it by grinding it down to size, taking out any deformations caused by the hardening process. A 0.001" (0.02mm) cut is a heavy cut.

It works on the same sort of principle as your little shaper, but it grinds rather than cuts. Take a grind, move across a bit, do another one.

I use mine mainly to get perfectly ground lathe tools, sliding faces and refacing my parallels. But now, I even use it for sharpening milling cutters. The list is endless.

It is the table that is the critical bit. It needs to sit, if possible, on precision bearing surfaces. You use the grinding head to grind the top surface of the working area (normally smaller than the table size) before commisioning and use of the machine. The table then runs true to the grinding spindle.

John

[Bernd]

I've got a small manual grinder. A freind of mine did a bit of dumpster diving to save this one. He took it home cleaned it up and then gave it to me. I think there's something wrong with the grinding spindle. When it shuting the grinding motor off the grinding spindle make s a weird noise, like the bearings are running dry. I've never been able to find any info on it either. I've asked in several other fora and no answers.

Here's a pic of it:



It grinds ok but leaves a bit of a wavy finish. It does good enough for lathe tool grinding. The jig sitting on the table is for sharpening a threading tool.

Bernd

[Darren]

It works on the same sort of principle as your little shaper, but it grinds rather than cuts. Take a grind, move across a bit, do another one.

Talking of shapers, I was sitting looking at mine tonight thinking, what if....

What if you mounted a grinding spindle in place of the clapper box?
As you say, the shaper takes a cut, moves across a bit and takes another cut. You have an indexing device in the form of a slide.
I think that about covers it dunit....?

[Bernd]

Darren,

If I remember correctly I saw or heard that one before. It should work.

Bernd

[bogstandard]

Unfortunately Darren, the surface grinder works on a little more precision than your shaper has got. It would work, but I don't think you would get the accuracy that is desired. Your shaper most probably works to the nearest thou or two, a normal surface grinder can work to 1/10th of that, or even better.

To knock a tiny pin in, you use a tiny hammer to achieve a good job. Use a sledge hammer to knock the same pin in, the results would be rather unpredicatable. Same same as above.

John

[Darren]

Point taken John, and understood....

[John Hill]

It works on the same sort of principle as your little shaper, but it grinds rather than cuts. Take a grind, move across a bit, do another one.

Talking of shapers, I was sitting looking at mine tonight thinking, what if....

What if you mounted a grinding spindle in place of the clapper box?
As you say, the shaper takes a cut, moves across a bit and takes another cut. You have an indexing device in the form of a slide.
I think that about covers it dunit....?

Persactly what I had in mind Darren, I even looked in the junk box and found a little spindle, must not get sidetracked, must not get sidetracked.

Unfortunately Darren, the surface grinder works on a little more precision than your shaper has got.

Eh what?  Do not go casting nasturtions by association at Sally Shaper!

[bogstandard]

John,

Would I do that to Sally?

But just to explain a little deeper.

For a surface grinder to do it's job correctly, you grind the table to the spindle. This is carried out every so often when the usually fairly soft top on the mag chuck gets damaged or worn, just to bring everything back into harmony. So fixed spindle, matching table.

You want to bolt the spindle onto a lump of metal that is pumping in and out with the running surfaces most probably made of metal to metal dovetails, or even worse.
You would only have to be a minute amount of a degree out on setup and if you took a very close up shot of the workpiece afterwards, it would most probably look like it was rows upon rows of sharks teeth.

The surface grinder works on the principle of that perfect alignment of spindle to table always being there.

Even Bernd with his rough spindled machine, with a terrible finish, would, I am sure, end up with a flatness you could only dream of Sally being able to do. We are not talking thous or tenths here, but undetectable with the measuring equipment we use.

John

[Darren]

For a surface grinder to do it's job correctly, you grind the table to the spindle. This is carried out every so often when the usually fairly soft top on the mag chuck gets damaged or worn, just to bring everything back into harmony. So fixed spindle, matching table.

I do that on the mill vice jaws. machine them true once it has been aligned and clamped down.

Can't get any squarer than that....

[Pelallito]

John,
You posted the following-I use mine mainly to get perfectly ground lathe tools, when talking about your surface grinder. What kind of jig do you use to hold the tools and set up the correct angles? I found the concept of sharpening my cutting bits on the surface grinder, intriguing to say the least.
Thanks again.
Fred

[bogstandard]

Hi Fred,

I hope my ramblings about the cutter sharpener straightened it out for you.

I actually use a combination of tilting/swivelling vice, a mini precision ground vice and a set of ground angle blocks.

I tend to spend a couple of hours doing them in batches rather than just a single one, and also tend to grind the same tip on either end of the toolsteel piece, it is just a matter of flipping it over after each operation.

I only do it because I haven't got too much grip in my right hand now for long grinding sessions on the offhand grinder.

Normally, I would go out and take a load of pics to show how I do it, and make up a post. But I am just preparing for a large project, so when the back is broken on that, I will make up a bit of a post to show you how.

John

[28ten]

That certainly is a nifty little project, it would make tool grinding a lot more accurate, for someone as unskilled as me.
when I started work at TWR Jaguar back in the 80's there was an old boy who would grind up all sorts of tools freehand, unfortunately he retired before i could get him to show me 

[John Hill]

Bogs, I understand what you are saying John however I assume a shaper mounted grinding spindle would allow one to grind hard materials that the regular shaper process could never handle and to get a finish at least as good as the shaper would (on softer material)?

I have some bits of tool steel (HSS I presume) that are just a tad too big for the shaper's tool holder and this would seem to be an ideal job for such a machine.

[bogstandard]

John,

If that is all you want to achieve, then that should do it.
My worry was that if you thought maybe you could achieve the same sort of precision as a surface grinder.


Cy,

Grinding lathe tooling by hand is rather easy. With a little practice, anyone can do it.

The main problem is the fear of not getting the angles just right.

Forget about that, they are only guidelines, just like a lot of other stuff that is spouted about. If you are near enough, and the geometry is basically there, and it is sharp and on centre, the tool will cut just fine.

As I have said, I only go for machine grinding because I don't have the flexibility and strength in my hand any more. I tend to drop lots of things.

Just have a look at all the garbage and piffle that is spouting on this ongoing post about it. How to become an expert toolgrinder overnight.

http://www.homemodelenginemachinist.com/index.php?topic=5569.0

By the time he has sharpened anything on that monstrosity, I could have done 20 freehand (if I didn't drop them), and they would most probably cut a lot better as well.

It is all down to getting your hands dirty and playing about. You soon pick up what is right or wrong. As for making form or profile tools, IMHO you can't beat a Dremel (or clone) with a thick fibre cutting disc and a set of radius gauges.

I know it sounds a little patronising, saying it is easy, but in all honesty, it is. Once you get the angles and the reasons for them being there sorted in your head, it just comes automatically. You will see how the cut is going on the lathe, think it is not quite right, lift the tool, a couple of seconds regrind, and you will be away again, with a perfect cut.

A lot of it is just plain common sense.

Bogs

[sbwhart]

Cy,

Grinding lathe tooling by hand is rather easy. With a little practice, anyone can do it.

The main problem is the fear of not getting the angles just right.

Forget about that, they are only guidelines, just like a lot of other stuff that is spouted about. If you are near enough, and the geometry is basically there, and it is sharp and on centre, the tool will cut just fine.

I know it sounds a little patronising, saying it is easy, but in all honesty, it is. Once you get the angles and the reasons for them being there sorted in your head, it just comes automatically. You will see how the cut is going on the lathe, think it is not quite right, lift the tool, a couple of seconds regrind, and you will be away again, with a perfect cut.

A lot of it is just plain common sense.

Bogs

Johns spot on with this, I grind all my lathe tools free hand its how we were taught as apprentices as long as you follow the basic geometry you can't go far wrong, the angles don't have to be exact to get a good cutting tool. 

Stew

[Stilldrillin]

Cy,

Grinding lathe tooling by hand is rather easy. With a little practice, anyone can do it.

The main problem is the fear of not getting the angles just right.

Forget about that, they are only guidelines, just like a lot of other stuff that is spouted about. If you are near enough, and the geometry is basically there, and it is sharp and on centre, the tool will cut just fine.

I know it sounds a little patronising, saying it is easy, but in all honesty, it is. Once you get the angles and the reasons for them being there sorted in your head, it just comes automatically. You will see how the cut is going on the lathe, think it is not quite right, lift the tool, a couple of seconds regrind, and you will be away again, with a perfect cut.

A lot of it is just plain common sense.

Bogs

Johns spot on with this, I grind all my lathe tools free hand its how we were taught as apprentices as long as you follow the basic geometry you can't go far wrong, the angles don't have to be exact to get a good cutting tool. 

Stew

They`re right, you know! 

David D

[28ten]

Cy,

Grinding lathe tooling by hand is rather easy. With a little practice, anyone can do it.

The main problem is the fear of not getting the angles just right.

Forget about that, they are only guidelines, just like a lot of other stuff that is spouted about. If you are near enough, and the geometry is basically there, and it is sharp and on centre, the tool will cut just fine.

I know it sounds a little patronising, saying it is easy, but in all honesty, it is. Once you get the angles and the reasons for them being there sorted in your head, it just comes automatically. You will see how the cut is going on the lathe, think it is not quite right, lift the tool, a couple of seconds regrind, and you will be away again, with a perfect cut.

A lot of it is just plain common sense.

Bogs

Johns spot on with this, I grind all my lathe tools free hand its how we were taught as apprentices as long as you follow the basic geometry you can't go far wrong, the angles don't have to be exact to get a good cutting tool. 

Stew

They`re right, you know! 

David D

I know I have just got lazy with my tooling. once the banana is fixed I will grind some up and you can laugh at my efforts 

[Pelallito]

John,
Good luck with your projects!
I was just curious on how you did it.
I was taught to free hand grind and can do it. For my way of thinking, the most important part of it is that the grinding wheel be properly balanced and ground flat across the faace. Needless to say, this is not a wheel altered as a form grinder. If the two things that I mentioned are done, the wheel spins perfectly smoothly with no vibration to transfer into the tool bit.
Thanks again.
Fred