New ideas for tool grinding in the workshop

For those of us interested in making our own version of the EMG12, or doing a similar job in a different way, maybe we should have a separate thread? Post your ideas and gadgets here!

I think that's a good idea John. My grinding facilities are simple, I have made a grinding jig for my bench grinder so I can grind lathe tools - see photo - and also grind drills.

I attached a 12mm diameter rod to the base of the grinder and the jig pivots on this shaft. At the right end there is an adjustment screw (on a sleeve) to set depth of cut and the jig can be unclamped from the sleeve and positioned close to the grinding wheel. The top swivels 360 deg. and can be tilted. The jig swings into the face of the wheel for grinding. Not very sophisticated but it works. In the left part of the photo there is a grinding support with a slot, this is used to grind toolbits for screwcutting.

Thor

 

Edited By Thor on 04/06/2015 06:48:24

This is a model of a T&C grinder which I am working on. Still a long way to go before manufacture. It has a 3MT spindle to accept a collet holder or the cutters which I use on my mill and lathe (which could be changed to accept R8 tools or other). The pivot/swivel tool holder will be replaceable for different grinding applications.

I intend to use a mini grinder motor with an assortment of different wheels. (may have to replace bearings if existing not accurate enough). Also looking at other motors to use as a grinder. Both the tool holder and the grinder can be rotated and moved to accommodate different angles.

Constructive comments about its design would be appreciated.

Paul.

Some simple tool grinders, more aimed at sharpening really are based on the tangent angle of a chord of a circle being proportional to it's heigh above or below the centre of the wheel. I've actually used one but can't remember how it was arranged to sharpen things like morse taper reamers even though it was demonstrated doing just that.

It was set up by measuring the diameter of the wheel and then setting the height from it's centre to obtain the desired angle - via a built in scale. Probably way too simple for many on here.

Bulk removal is a different problem and I am happy doing that by hand.

John

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That's a very good point of reference for this discussion.

... Helps get the spec. defined properly.

MichaelG.

Edited By Michael Gilligan on 04/06/2015 10:39:51

Hi Paul

I like your concept drawing. I have been looking at the Quorn design for a while and there is just to must work. Your design with the linear rails will be quicker and easier. What cad package do you use. I work in Solidworks and i am willing to work on the design with you

Kenn

What about a specification?

1. What will it be expected to do?
2. To what level of precision and accuracy?
3. With what amount of ease of use/automation?

The quorn has a high score for the first two, and a very low score for the last one, for example. There will always be a pay-off between flexibility and ease-of-use.

Other issues worth considering:

1. Need for any off-the shelf parts
2. Need for bespoke castings or laser cut components
3. Continuous or intermittent use
4. Physical size and weight limits
5. Budget
6. Durability
7. Safety in use

If you do a one-man build then these things are tackled almost subconsciously, but for a shared project they are needed to 'define the envelope'.

Naturally options and pay-offs can be explored, but the first thing is to decide what the basic function of the machine will be!

Neil

This is what I use.It is made from a cross vice and cheap bench grinder. There are more pictures in my tool grinder album.

Les.

Has anybody got any views or comments on the new Acute system from Eccentric Engineering, it was on display at Harrogate but I was too busy buying other bits to get a good look at it. I think it was available as a kit of bits or just drawings

Kenn, a version of the Bonelle has been done in Solidworks whch is looking like a barstock version of the Quorn. Which is odd as I thought the Bonelle was a barstock version of the Stent which is what Paul has produced.

> Acute system from Eccentric Engineering

A couple of pictures and short description in the next MEW, more detail soon. In essence it's a lot of very cleverly designed jigs that work with a parallel motion/pantograph to control the movement of the parts.

Looked very cleverly thought out, but if making from the (mostly laser cut) kit a degree of care would be needed, mainly to avoid slop caused by making holes over-size.

Neil

That's just an IGS file ie one solid lump. You couldn't do much with it even if you imported it into Solidworks.

Grabcad seems to have a real problem with people uploading files that they describe as Solidworks files when in fact they are IGS or STP.

STP imports are often just as bad - although you get all the individual parts, the mates have been lost. Unfortunately, you often find you can't simply remake the mates because the components aren't proper parametric models, even if you try to use the function that makes models from STP imports.

This one is tantalising, as it actually looks like a properly modelled assembly. Much of the work on Grabcad is only for "cosmetic" use. Perhaps the owner might send you the actual SW files if you ask.

Murray

Hi Neil,

I am tying to simplify the grinder design, and use commercial parts (sourced the linear bearings and lead screws from fleebay for a good price), catering for most of your comments and trying to incorporate features which I have seen in other designs.

Kenn, It is modeled in Solidworks andI appreciate your offer to assist but would like to do it by myself . I used to work as a design draftsman but have now retired, This project allows me to keep my CAD skills up to date and my mind active. (they say you keel over if the mind stops working).

Will post more details after I have developed it further, Paul.

If you haven't got a tool & cutter grinder, I find a simple way to rejuvenate an end mill is to grind a (quite subtle) spherical concave shape onto the tip.

I normally do this freehand on the bench grinder using the corner of the wheel, but I'm sure the results would be neater if I rigged up a decent cutter holding device, which would simply be a way to rotate the tool whilst steadily presenting it to the wheel. I've tried to show how this shaping technique automatically provides the necessary clearance angles in the CAD mock-up pictured below. The green disc represents the abrasive wheel and the dark blue area is the spherical surface produced by grinding.

Martin.

Edited By blowlamp on 04/06/2015 23:41:47

Edited By blowlamp on 04/06/2015 23:46:22

OK for going in from the side Martin but won;t handle plunge cuts.

God logical thinking though

Agreed, I forgot to mention that you can't do the usual plunge cuts, although I have been able to squeeze the odd couple of thou plunge for cleaning up a surface - it's really just a quick way to get some more use from an end mill without a lot of bother and good for altering tee-slot cutters.

Martin.

The description says the parts are "laser-cut and spot-drilled" which I presume means they have pilots for the holes and you finish them yourself - so you do at least have control over this.

.

Neil,

Would you be able to set-up one of your 'voting' schemes on a seperate thread ?

Although more commonly used for things like Software Development, the 'MoSCoW analysis' would suit this project very well ... it's an excellent way of focussing the collective mind.

MichaelG.

Yes, it's all very well thought out, hence my comment was on hole sizes not positions!

That Acute system looks interesting, quite different from anything else I've seen. Any idea of price?