expensive T&C grinders : grinding jig for circular cutting tools ?

B

BillWood

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Following a question raised in a recent thread .......... Am curious, Does anything like this exist as an accessory for the fancy tool and cutter grinders ?

Although I grind tools by hand I have often wondered if its possible to make a jig that would allow me to grind an absolutely perfect semicircle on the end of a piece of tool steel without engaging my brain or eye hand co-ordination.

Would maybe be something like a tiny version of the steve bedair ball turning jig but instead of the tool cutting the workpiece it works the other way around with the tip of the tool rotating against the wheel and being ground into a semi circle.

Or even simpler, a pin on a table that engages into a hole in a toolholder and the pivot point is advanced into the wheel until the desired radius is achieved.

Am curious, Does anything like this exist as an accessory for the fancy tool and cutter grinders ?
 
Yes. Most of the manufacturer's that make the full on Tool & Cutter grinders offer quite a range of accessories. There are also a number of non-OEM manufacturer's of accessories for T&C grinders (one example would be a the Eldorado gun drill sharpening attachment from Sterling - can be used on most any T&C grinder).

In fact, it is these attachments that really make the T&C grinder a useful tool. Generally, a T&C grinder with no attachments is really just a boat anchor. The attachments (used) can go for some serious coin.

A radius grinding attachment would be a pretty standard offering. I have a Cincinnati #2 T&C grinder - it is a very common good quality grinder that have been available for at least 100 years (with not a lot of changes) and has been copied by a number of other makers.

I do not have a radius grinding attachment. But for more than 5x what I paid for my grinder - I could have an RGA: https://www.ebay.com/itm/Cincinnati...467044?hash=item33df0c72a4:g:-78AAOSwLI1aUTGM
 
Tool and cutter grinders are extremely versatile. They are designed to grind most anything that comes along that will fit in the machine envelope. However, for that to happen, you also need to have a lot of ways to hold and move work. Attachments. It pays to have a lot of them, and be ready to make any jig or fixture you need to get the job done.

The smaller tool and cutter grinders, like the Deckel SO and similar clones, are often used for grinding end mills and sharpening other tools. They have a small envelope and fewer attachments. Still, useful machines.
https://www.bing.com/images/search?...-30&sk=&cvid=41BFA0D697684A5693594190EC4FB355

The larger T&C grinders like the Cincinnati #2 and many others, are suitable for larger work for bigger machines, and for all kinds of custom grinding work, even for surface grinding. They are as large as knee mills, and need some kind of setup for every new job they do. Some of those machines are dedicated to a particular job (and so are Deckel types), and so never change their setup. In a job shop, where lots of things are made and repaired, and tools are needed to make them, historically those machines were indispensable and the key to getting work done. These days, shops want to have a machine for every purpose, and buy tooling as needed for new jobs and have the tooling shipped in by air freight.

In my opinion, a hobby shop is more like the old shops with the T & C grinder and at least one guy who was a master of making every kind of special tooling that anyone needed. CNC has changed that picture forever, for better and for worse. The old T & C machines are mostly rusting away, mostly because no one knows what to do with them or has time to do the work, and also from the notion than time is money.

Edit: I see that Chipper5783 and I were posting much the same story at the same time...

Second edit: Why do I not see much CNC grinding work? A NC grinder could do a lot of those jobs, especially if it was designed to be be rapidly reconfigured and programmed. I am NOT a CNC guy, but I do understand some of what they can do and appreciate their place in the machining world. What will it take to have CNC machines that can make quick and dirty setups for shop auxiliary work? Probably a smart and fast code writer at this point. Comments, please...
 
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Thanks for the replies. I checked the ebay link that chipper posted.

Thats amazing ! - The radius grinding jig is likely to cost more than my 9" lathe + RF30 Round column mill + all my tools (all 2nd hand).

Will continue to ponder my ball turner type of radius grinder.

Bill
 
Look for a K O Lee radius grinding fixture, they usually go for about $600-900. I have one for my T & C grinder. Nice to have when you need one.

Edit: you could make one fairly easy. The problem you get into is how do you make your adjustments for the proper radius and be able to offset either left or right for the proper radius placement.
 
BillWood said:
Following a question raised in a recent thread .......... Am curious, Does anything like this exist as an accessory for the fancy tool and cutter grinders ?
Click to expand...
Shaping an arbitrary profile with a grinder, is the general description of a tool
every locksmith/key shop has.
 
whitmore said:
Shaping an arbitrary profile with a grinder, is the general description of a tool
every locksmith/key shop has.
Click to expand...

Not sure but I think I understand.

If a machine can copy keys then it should also be able to copy a semi-circle ?

Bill
 
BillWood said:
If a machine can copy keys then it should also be able to copy a semi-circle ?
Click to expand...

I think the various keycutter machines are designs that could easily be adapted
to the replication of lathe bit profiles. If one doesn't need production speed, the
big-tool grinders with their tooling are possibly overkill.

This one is typical: note the left/right sliding mechanism, and the (left-side) stylus
that rides against the pattern, while (right-side) a wheel cuts the workpiece.
keycutter.png
 
Thanks Whitmore,

Did some googling and basic keycutting gadgets like that one are quite cheap on aliexpress.

Thats basically a 2d pantograph.

You have opened up a whole new avenue of thought for me.

ie I've seen youtube videos of carbide millbits cutting toolsteel, I've seen various router based copying jigs, have seen really skinny grinding wheels or ordinary wheels shaped to a point.

Any of our fellow forumites taken this idea further in the past ? Will do some googling .................

Bill
 
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