cylindrical grinding on a TCG

[bob ward]

I need to reduce 200mm of 16mm 1020 to .621". I'm thinking that this could be a good first job for my CC Engineering TCG but I have a few questions of those experienced with a TCG.

1. I've done a dummy set up, it seems the only way I can get 200mm travel is to turn the grinding wheel at an angle to the work. Is that an approved/ normal practice?

2. The present work holding arrangement consists of a point on the drive end and a spring loaded point at the tail stock end. Is that sufficient/usual to keep the work turing against the wheel?

3. No guard on the wheel and it doesn't look like there ever was a guard. Is that a feature from times when men were men etc or is it normal procedure for TCGs?

http://i237.photobucket.com/albums/ff28/sirrobertthegood/IMG_0039_zpse3b22554.jpg (http://s237.photobucket.com/user/sirrobertthegood/media/IMG_0039_zpse3b22554.jpg.html)

[Stustoys]

Hi Bob,

Something looks strange. Why do you need the angle? Something is fouling between the wheel head and the work head?

Is there any chance the motor is up side down so the wheel is mounted on the wrong side of the spindle?

Stuart

p.s. re guards........ If I recall correctly there is sort of a 1/4 guard mounted from the U's above the spindle. I might have some pictures some where or maybe they are in the thread about my CC

[.RC.]

1. I've done a dummy set up, it seems the only way I can get 200mm travel is to turn the grinding wheel at an angle to the work. Is that an approved/ normal practice?




I have seen somewhere that running the wheelhead at an angle is common CNC cylindrical grinder practice. It is so the grinder can do straight and then grind a shoulder square at the same time. The wheel is dressed appropriately..

[Stustoys]

You might find something useful in this thread if you haven't seen it already

http://www.woodworkforums.com/showthread.php?t=140000

Stuart

[Pete F]

Bob please let us know how you get on with this regarding finish. I'm considering setting mine up for cylindrical grinding, but have heard various reports about expected finish.

With regard the the wheel guard, I can't generalise, and know nothing about yours, but yes my Clarkson has wheel guards (indeed an extraction system). I've never personally had a wheel explode (touch wood) but I've spoken with people who have and apparently it's a time when ones undies disappear up places where they were never intended to go, and visa versa. I'm not sure how much good they do in these situations, but I personally always use guards on grinders.

[easymike29]

From your earlier posting.

Gene

[Zsteve]

Think you will need a drive dog on the bar as a point is not going to be enough to drive it properly. No probs with the wheel at an angle but you will need to dress a the wheel so you have a 'flat' in contact with the bar when grinding. Nothing stopping you using it without a wheel guard but may be a good idea to get one at some point.

[simonl]

Hi all,

Finding this thread interesting and indeed I will be keen to see what surface finishes can be achieved. I have a question regarding the rotation/direction of the grinding wheel wrt the workpiece. One would assume (yes dangerous) that both grinding wheel and workpiece would need to rotate in the same direction (as opposed to an analogy with 2 gears which travel in opposite directions) otherwise you can get a situation where the surface speed of the grinding wheel could be reduced to near zero. Is this assumption correct? What speed range would you rotate the workpiece, I assume it does not need to be as fast as the grinding wheel, is it too dictated by the diameter and surface speed?

Cheers,

Simon

[Stustoys]

Hi Simon



One would assume (yes dangerous) that both grinding wheel and workpiece would need to rotate in the same direction

Well they do......do they need to? well people try all sorts of things when they are after a mirror :)


otherwise you can get a situation where the surface speed of the grinding wheel could be reduced to near zero.
You'd need a large work piece and/or a very fast work head to get close to zero..... I'm not sure I'd want to be around, but if you managed it, you'd likely end up with high speed crush dresser.


What speed range would you rotate the workpiece,
Must say I dont have a number on that....I'll make a WAG at around 200rpm. But I've only used grinders around the size of BT's... maybe bigger ones go slower?

Stuart

[bob ward]

If I'm reading correctly the data plate on the geared motor that rotates the workpiece, the output speed is 145RPM. Then there are 2 pulley options between that motor and the work piece to give final drives of roughly either 100 or 300 RPM.

[Stustoys]

I'll make a WAG at around 200rpm.


roughly either 100 or 300 RPM.

Do I get a point for that? lol

Hi Bob,

I'm still not seeing the problem. As pictured you have enough left travel to grind to the tailstock end? Shouldn't you have heaps of travel to the right? So is it a Y issue

Stuart

[Machtool]

I have seen somewhere that running the wheelhead at an angle is common CNC cylindrical grinder practice.
Plenty of manual production grinders had the wheel head slide mounted at a 30 degree in-feed angle.You know how the sine of 30 deg is 0.5. That way it would take off the same amount off the face as it did on the diameter.

They used to be very common in the auto industry, for grinding things like pinions and gears. Anything with a shoulder that needed to be true to the journal.

Regards Phil

[simonl]

Do I get a point for that? lol

Stuart

Yes, I'll give you a 100 points for that!

Simon

[Burner]

Can you swap the tailstock and workhead around? That would place the drive for the workhead away from the grinding wheel and then not need the angle on the grinding wheel? It would look from the pic as though it would work better. You should be able to reverse the direction of the rotation of the workhead either electrically or mechanically.

There is a bracket to hang a gaurd on top of the grinding head, the U shaped brackets. I would spend the time making a gaurd, otherwise you may end up with a saw head!

If you use the setup as pictured I would check that the wheel you select can accept the side load from ginding on an angle. I have only seen it done with saucer shaped wheels on a T&C.