South Bend Grinding Block Dimensions

I have inherited a 9A and included with the lathe were 3 inserts for what I have now identified as a South Bend cutter bit grinding block. Unfortunately the block was not included or got lost in shipping. I'm wondering if there is some kind soul that could supply me with the dimensions of the block. I'm sure I can figure out everything to get it to function, but would like to have a relatively close copy of the original. Even the angle of the heel would help.



Nothing to do with South Bend, but I made my first gear and feel compelled to show it to everyone.

Dimensions I do not have as these photos were posted by someone else.
Knowing the front clearance angle of the tools to grind should be a starting point.

John

Thanks for the reply. That told me what the larger hole on the block is for. During my continued search I came across this. Found it at Anyone have Home Shop Machinist May/June 1986 - Shop Floor Talk in post #4. Not sure how handy a grinding block will be, but easy enough to make..... says the guy who has never made any cutting tools.

Cyborg said:

Not sure how handy a grinding block will be, but easy enough to make..... says the guy who has never made any cutting tools.

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My grandfather had a set of these blocks (and now I have them). They appear to have never been used. I also have never used them. The only real accuracy you need in grinding your bits is for threading tools with exact angles. You can eyeball the rest.

Thanks, for the "help".

SLK001 said:

My grandfather had a set of these blocks (and now I have them). They appear to have never been used. I also have never used them. The only real accuracy you need in grinding your bits is for threading tools with exact angles. You can eyeball the rest.

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I have a nice copy of the this tool and look forward to using it when my lathe us ready to run! Nothing wrong with making good looking cutting tools that are uniform IMO. I imagine that using the tool will help isolate my hand from the heat a bit too.

Cyborg, thanks for the link to the other pics and instructions. I nabbed them and saved them in a file. Although I have done a lot of off-hand tool grinding for radius tool and drills, a fixture is a bonus to use when making 60 degree and Acme threading tools.
John

jhruska said:

Cyborg, thanks for the link to the other pics and instructions. I nabbed them and saved them in a file. Although I have done a lot of off-hand tool grinding for radius tool and drills, a fixture is a bonus to use when making 60 degree and Acme threading tools.
John

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I guess I'm missing something. It's not clear to me how this particular fixture helps making 60-deg or Acme thread cutter. As far as I can see, one will need to provide an additional fixture for mitering while the block will only help with relief angles.

Please correct me if I'm wrong.

MichaelP said:

I guess I'm missing something. It's not clear to me how this particular fixture helps making 60-deg or Acme thread cutter. As far as I can see, one will need to provide an additional fixture for mitering while the block will only help with relief angles.

Please correct me if I'm wrong.

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You are right, but it is a step up from free-hand grinding. Not many will have resources or coin for repeatable set-ups.
John

jhruska said:

You are right, but it is a step up from free-hand grinding. Not many will have resources or coin for repeatable set-ups.
John

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Yes and if you are not blessed with a particularly nice grinder I think is a big step up.

Kevin T said:

Yes and if you are not blessed with a particularly nice grinder I think is a big step up.

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Since you brought the subject up.... I have a small but nice Delta grinder, but don't see it being up to the task. Along with the lathe etc, I inherited an "off shore" grinder which is 3/4 HP and has 8" stones. Unfortunately before it even gets up to speed, it makes me want to head for the hills. I tried it with a good quality (at least I think it is) 6" stone and it wasn't any better. A DR shows runout on the shaft at about ,0045" and the shoulder that the stone buts up against is almost non existent and questionable at best. I think it may survive as a light duty buffing setup. So after that ramble... what would you recommend for a grinder and what would you recommend for stones. Whatever I get, I expect to have to modify it to support the grinding block setup.

SLK001 said:

My grandfather had a set of these blocks (and now I have them). They appear to have never been used. I also have never used them. The only real accuracy you need in grinding your bits is for threading tools with exact angles. You can eyeball the rest.

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I've seen the local wizard grinding them freehand and he wouldn't disagree with you. My situation is... I have never ground any, so I'm assuming that the block will help me through the learning curve. I have a stack of books that cover the subject, but my attention deficit disorder has led me to Youtube where I found a couple of decent videos. I picked up the steel today for $3 and it shouldn't take long to machine it, so even if it does end up collecting dust eventually, it'll give me some practice time on the mill.

Let me be the first to say, "WOW", on your gear.
Looks great.
I have a grinding block if you need any more information.
And welcome to PM.

maynah said:

Let me be the first to say, "WOW", on your gear.
Looks great.
I have a grinding block if you need any more information.
And welcome to PM.

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Thanks... Its for the power feed on the mill. The maker no longer exists and parts are no longer available. I have to confess that the original gears demise was due to my stupidity and aforementioned ADD. I attempted to decipher the gear cutting section in the Machinery's Handbook, but it was pretty heavy going for a newby. Found a couple of good videos and then just sat and stared at the dividing head until the light finally came on. I must say that it is a gratifying experience when you make the final pass and the last tooth is identical to all the rest.

Regarding videos... this fellow has quite a few and are usually entertaining along with being informative. YouTube

Cyborg said:

.... I have a small but nice Delta grinder, but don't see it being up to the task. Along with the lathe etc, I inherited an "off shore" grinder which is 3/4 HP and has 8" stones. Unfortunately before it even gets up to speed, it makes me want to head for the hills. I tried it with a good quality (at least I think it is) 6" stone and it wasn't any better. A DR shows runout on the shaft at about ,0045" and the shoulder that the stone buts up against is almost non existent and questionable at best. .

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Norton grinding and wheel selection as a downloaded pdf:
vintagemachinery.org/pubs/1834/6637.pdf

Grinder basics:
Safety Glasses
Never wear gloves
Dressing Tool, best is a diamond mounted in a holder passed across the face of the wheel.
Grinding Wheel, paper blotter on each side and a 'cupped washer' (flange) on each side of the wheel.
Grinder Wheels can range from hard to soft, coarse to fine grain size, strong to weak bond of grains.
Motor RPM is constant. Grinding wheel peripheral speed depends on diameter. Calculated as Surface Speed

Grinding wheels are manufactured with a range of properties. Grain-grit size, Bond strength from (A) friable to (Z) strong, Structure as open or closed, and type of abrasive.

A wheel that is designated as hard may burn and over heat steel while turning at that wheels rated rpm. That same wheel will cut 'soft' at a smaller diameter (therefore a slower surface speed). Likewise a 'soft' wheel will seem 'hard' at a higher rpm.

Choose the correct wheel for the work that you will do and that 'inferior' grinder may perform well.
Fasten the grinder so it cannot move. The work rest should be about 1/16 from the face of wheel.
Or build a larger solid tool rest out of a hard surface. Particle board with a tough veneer will work, replace as it wears.
There is so much more to effective grinding than this.
I hope it gets you on track to productive tool grinding.
Train your hands to repeat movements when grinding. Movements using the shoulders are better than flexing the wrists.

John

The HSS tool should not get so hot that the tool turns light brown or blue at the edge. Have some water nearby to keep the tool below the 'hot zone'. Quench the opposite end to draw the heat to avoid thermal cracks.
HSS: grind with an aluminum oxide wheel - generally
Carbide: grind with a silicon carbide wheel and never grind any steel or iron with this wheel

True the wheel each time a new wheel is mounted.
A ring test of a wheel should produce a clean clear sound, not a fuzzy one. Hang by a string or cord, tap and rotate. wood hammer handle should work ok.

Thanks for taking the time to post that.. its appreciated. I downloaded the PDF and took a quick scan though it. Whole nother world out there! There was a box of stones that I inherited as well. Some I assume are good quality based on the price tags which indicate someone took the trouble to import them from the UK. Too bad the unused 3/4 hp grinder is such a piece of dung and I'm assuming I'd be much better off with something more substantial than the Delta even though the volume of work will be pretty limited.

Forgot to mention grinding dust. Think of it as a toxin for the lungs. Silicosis - silicon carbide grinding wheels related topic.
Grinding wheels of different colors are sold. 'Generally' they start out as white base material so color sometimes is the manufacturers attempt to distinguish their product. Red grinding wheels are an example.
There are sleeves for the holes in the wheels so they can be used on different size arbors.

I would use the import grinder. Attach it to a solid bench top. If it spools up and runs too fast change the wheel to a smaller diameter.
Nice cup wheels, preferred for grinding the side of the tool.
Regards, john

I have a good selection of masks and respirators, but a reminder doesn’t hurt. I tend to forgo the mask if I’m doing something quick and know I shouldn’t.
The thing about the import grinder is the runout on the shaft. It has 8” stones and tried a 6, but it was just as bad. The stones that came with it didn’t have sleeves (the 6” I put on did) there was just a bit of white goop between the shaft and the stone.... perhaps in an effort to take up clearance?
I think I’ll just use it for buffing. Anything spinning that vibrates that much gives me the willies. There is an older (used) heavy duty one with 8” stones for sale in the neighbourhood for $60, so may go have a look at it.

There is a reproduction South Bend cutter gage available on ebay. $12.99/2.00. Same guy makes a re-pro grinding block set.
search terms South Bend cutter gage

John

Thanks. I’ll order one, but first need to search some bins to make sure there isn’t one lurking in there. There is a fair amount of stuff that came with the lathe and mill.