PDA

View Full Version : Need ideas for a T&C grinder head



Spandau
01-03-2011, 01:32 PM
A good friend just gave me this, as he needed to make some quick space in his shop for new arrivals...It's a KO Lee model A600 tool & cutter grinder.

http://pic50.picturetrail.com:80/VOL475/11553299/20726273/394388577.jpg


It apparently did some time making stuff for the US war effort--if I am decoding the serial tag properly, this was made in March of '43.

http://pic50.picturetrail.com:80/VOL475/11553299/20726273/394388576.jpg

It is obviously lacking a grinding head. I am wondering what my best course of action would be to put this back into service as a tool & cutter grinder? I would prefer to buy/use something off the shelf and modify it, rather than making something totally from scratch...

I have air grinders, various early Dumore TPG's, a couple of older bench grinders, various bearing pillow blocks, etc. I also have access to a large surplus center (Mendelson's in Dayton), as well as some well stocked scrap yards.


Here is what the original looks like (from a 4 page PFD. from OWWM): http://www.owwm.com/pubs/detail.aspx?id=3777

http://www.owwm.com/pubs/1738/3777_s.png


Any insight or opinions would be greatly appreciated! :)

Regards, Ken

JCHannum
01-03-2011, 01:49 PM
I have a friend who adapted a toolpost grinder to a similar T&C grinder with good results.

Fred White
01-03-2011, 01:56 PM
I have the same grinder and the grinder head is basically just a motor. A small bench grinder or a Tool Post Grinder should work. I'd do whatever is easiest as a starting point. They are a good basic machine.

I was going to make mine into a drill bit sharpener for larger bits, but I haven't gotten around to it.

Toolguy
01-03-2011, 02:30 PM
Maybe you could start with one of those double ended grinders from HF. Then all you would have to do is adapt to the spindle on the moving table side.

Mcgyver
01-03-2011, 02:56 PM
I have the same grinder and the grinder head is basically just a motor. A small bench grinder or a Tool Post Grinder should work. I'd do whatever is easiest as a starting point.

I'd add to that that the motor would have been quite well balanced; A good tool post grinder would work but you might not be happy with a regular electric motor or bench grinder. Its possible though that a local spindle shop could dynamically balance a regular or grinder motor; if you change the bearings on a surface grinder motor for example they balance it as well. I looked into it once, wasn't prohibitive (cant remember exactly how much) . grinding tools doesn't need to have the same finish as a surface or cylindrical grinder, but it has to be pretty good

metalmagpie
01-04-2011, 07:55 AM
1. Watch ebay for the right part until you get sick of it
2. Dump industrial detritus on the next willing recipient
3. Move on

bob ward
01-04-2011, 08:10 AM
Here's a complete one of that style, you may glean some ideas for the missing pieces.

http://cgi.ebay.com.au/Universal-Tool-Cutter-Grinder-/320636879794?pt=LH_DefaultDomain_15&hash=item4aa77283b2#ht_500wt_1156

MuellerNick
01-04-2011, 08:28 AM
I wouldn't add a bench grinder. They generally do have too much axial play. You'll be astonished what crapy results you get when grinding on the side of the wheel (that being very common in tool grinding).


Nick

willmac
01-04-2011, 10:07 AM
Adapt the wheelhead design from a Quorn. Perhaps make it a bit bigger. The spindle design on the Quorn is quite good and would suit the vertical pillar of your grinder.

lazlo
01-04-2011, 10:28 AM
Adapt the wheelhead design from a Quorn. Perhaps make it a bit bigger. The spindle design on the Quorn is quite good and would suit the vertical pillar of your grinder.

That sounds like a great idea. There's a guy on the Yahoo Tool & Cutter Grinder group that made his own wheelhead for an old K.O. Lee.

http://groups.yahoo.com/group/ToolGrinding/?yguid=92583912

Lane has an A600 IIRC -- you might bounce some idea off him...

Spandau
01-04-2011, 11:26 AM
Thanks for the insight fellows!

I think I'm going to try one of these first:

http://pic50.picturetrail.com:80/VOL475/11553299/20595630/394405768.jpg

They are Dumore 2AG tool post grinders, of which I have 4, plus 2 others that are parts units.

I plan on using one of these just to get the hang of using a T&C grinder, meanwhile I'll be hatching a plan for a more permanent grinder head.

A friend is offering me the spindle assembly from a Cincinnati Monoset for cheap; it's filthy, but the bearings are good, but it may be too big for this little grinder base :confused:

A local engine shop is auctioning a couple of benchtop Van Norman valve grinders in a week, I might try to get one cheap so I can (maybe) kludge the head off of it. Will have to look them over to see if this is feasible.

Anyway, thanks again for the help, and I'll update the forum as to the end result of this quest :)

Regards, Ken

MuellerNick
01-04-2011, 12:21 PM
They are Dumore 2AG tool post grinders,

Before waisting time, check the axial play. Tool post grinders can live with that.

And why is the axial play important?
You often grind at the side of the wheel (grinding in flutes). Or if you grind a lathe bit, it is also often done with the side of the wheel. Now if you have a cup wheel and pass along the wheels cutting area with the bit, the wheel will cut more if you enter or leave the cutting area. Thus the surface won't be straight.


Nick

Spandau
01-04-2011, 01:00 PM
Nick, thanks for your thoughts. What would be the proper method for checking the axial play in these TPG's? Is there an acceptable level of movement before it is considered too loose to use as a T&C grinder head?

Regards, Ken



Before waisting time, check the axial play. Tool post grinders can live with that.

And why is the axial play important?
You often grind at the side of the wheel (grinding in flutes). Or if you grind a lathe bit, it is also often done with the side of the wheel. Now if you have a cup wheel and pass along the wheels cutting area with the bit, the wheel will cut more if you enter or leave the cutting area. Thus the surface won't be straight.


Nick

form_change
01-04-2011, 01:38 PM
A single phase bench grinder (or that style of grinder) sometimes has a centrifugal switch to cut the starting coil in and out. I notice on my bench grinder that when starting the wheels will move sideways say 1/4" when this cuts out.
My suggestion would be to use a belt driven toolpost grinder. That way the motor axial movement won't matter as the spindle is controlling the sideways movement.
I don't agree that a home workshop T&C grinder's axial movement should not be a concern, for 2 reasons - firstly, there are times when the 'end' of the wheel is used, so DOC could be affected and secondly, in a home workshop equipment is not always used strictly for its intended purpose. If I had a T&C grinder like that I'd also be using it for surface and centre grinding. Axial play may matter in that case.

Michael

MuellerNick
01-04-2011, 01:49 PM
Is there an acceptable level of movement before it is considered too loose to use as a T&C grinder head?

Anything greater than zero is too much. Well, maybe 0.01 mm. It should have preloaded bearings. Your spindle head might have them.

The Quorn/Bonelle is a good idea, but ...
* requires work ;)
* changing wheels is not very convenient with that construction. And making wheel adapter even less. You should change the business end of the Quorn.


Nick

willmac
01-04-2011, 01:55 PM
The design I suggested has angular contact bearings under pre-load. It is specifically intended for this type of application.

Nick - I'm not sure why you think that changing wheels with this design is difficult; It has a drawbar arrangement where you can have many wheels already set up on their arbors and change them very quickly.

The problem is that you will have to make it.

MuellerNick
01-04-2011, 02:15 PM
Nick - I'm not sure why you think that changing wheels with this design is difficult;

Actually, I don't know why I wrote that. :confused:
But what I don't like is the drawbar-design. IIRC, the arbor and the drawbar is one part. A waste of material (I'm cheap) and not convenient to store away. You'll have lots of wheels mounted on arbors!
The other thing is, that the cone is IN the spindle (a conical bore). It should be outside (a conical shaft). That's a stiffer setup, because the cone is quite at the CofG.


Nick

JCHannum
01-04-2011, 02:18 PM
The old plane bearing motors would display end play, but would float to center under power and be held there quite firmly by the magnetic forces. Most of the time, when sharpening milling cutters and such, material removal and forces required are minimal. Those grinders might work just fine. They are probably very high RPM though and that might pose a problem with larger stones.

Spandau
01-04-2011, 06:47 PM
Apparently the yahoo! grinder group is so exclusive that membership is like gold---my request was denied. Maybe it's run by that crazy Nelson guy like the former SB group???

Anyway, thanks again for the information fellows, I plan on trying a few things and will report back when I've got something satisfactory.

Ken