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Cutter Grinder
- Thread starter JPigg55
- Start date
- Joined
- Apr 20, 2011
- Messages
- 430
This is really one of those questions --well, that depends?
Do you want one of the dedicated end mill sharpeners (often called T&CGs) (Darex, Cuttermaster) Usual range of cost is $1000 & up (usually & up!
Then there are the large multi function machines that are truly "tool & cutter grinders". On these you have to ask your self what are your skill levels for using one of the multifunctions T&CG -can you utilize all the various attachments that are out there for the larger T&CGs - can you afford the cost of obtaining these attachments that are almost certainly gonna be missing from the machine? These machines can be seen relatively cheap - $4-500, but these are usually the ones that have no accessories (air bearings is a must) and as such are virtually worthless with out them.
If youre gonna occasionally sharpen end mills then the Darex types will be the choice, but only you can say whether the up front cost is worth it.
In my case I just had to have a TCG (end mill grinder) so I finally found a Cuttermaster (which will do very little except endmills) for $550 about 5 yrs ago - so have I got my money back out of it, or would I do it again? I'm not sure... I definitely dont NEED it. It was kinda fun getting to master the art of actually sharpening an end mill (which is not easily learned) and I have reclaimed probably a couple hundred EMs.
So, I would say do your homework on what these machines are and learn them to help decide what to do.
Do you want one of the dedicated end mill sharpeners (often called T&CGs) (Darex, Cuttermaster) Usual range of cost is $1000 & up (usually & up!
Then there are the large multi function machines that are truly "tool & cutter grinders". On these you have to ask your self what are your skill levels for using one of the multifunctions T&CG -can you utilize all the various attachments that are out there for the larger T&CGs - can you afford the cost of obtaining these attachments that are almost certainly gonna be missing from the machine? These machines can be seen relatively cheap - $4-500, but these are usually the ones that have no accessories (air bearings is a must) and as such are virtually worthless with out them.
If youre gonna occasionally sharpen end mills then the Darex types will be the choice, but only you can say whether the up front cost is worth it.
In my case I just had to have a TCG (end mill grinder) so I finally found a Cuttermaster (which will do very little except endmills) for $550 about 5 yrs ago - so have I got my money back out of it, or would I do it again? I'm not sure... I definitely dont NEED it. It was kinda fun getting to master the art of actually sharpening an end mill (which is not easily learned) and I have reclaimed probably a couple hundred EMs.
So, I would say do your homework on what these machines are and learn them to help decide what to do.
At one time I had a retired machinist with a tool and cutter grinder who would grind cutters very reasonably. He is now completely retired. This is what I would recommend, if you can find someone, Im looking and will post it here if I find someone and he is willing to sharpen for others.
I picked up a used K. O. Lee for 200 bucks. It needs to be gone through but it is functional. I recently corresponded with a fellow in Michigan (I think) who had his up on ebay for 600 dollars. This machine was in reasonably good shape. I would have picked it up but the shipping made it over 1500.
One thing, it helps to find an air bearing. These are available but you'll have to do some looking if you want one for under say 600.
Just my 2 cents.
Jon
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Pacer . . . very cool!!!
K.O. Lee has a book that covers how to use their tool. I agree it's nice to develop the skill to do the work. Bellsaw made a little machine to sharpen carbide router bits. This is adaptable for a variety of tooling.
A quick search of the internet may reveal some forums where fellas have restored their K. O. Lees.
One thing, it helps to find an air bearing. These are available but you'll have to do some looking if you want one for under say 600.
Just my 2 cents.
Jon
- - - Updated - - -
Pacer . . . very cool!!!
K.O. Lee has a book that covers how to use their tool. I agree it's nice to develop the skill to do the work. Bellsaw made a little machine to sharpen carbide router bits. This is adaptable for a variety of tooling. A quick search of the internet may reveal some forums where fellas have restored their K. O. Lees.
Last edited:
- Joined
- Aug 14, 2011
- Messages
- 101
Hello JPigg55, let me offer another approach to the cutter grinder problem. As hobbyists we have a constant need for sharpening things. Drill bits, lathe tools, end mills, etc. As hobbyists we cannot afford to continue to buy new tools when the old one gets worn or or damaged. I use a lot of carbide tools and the cost of replacing these when they are in need of some attention would put me in the budget dog house.
Buying a used Darex or similar type unit and reworking it to meet your needs is a good approach. But why not build your own? I had this same dilemma a few years back and after researching the subject decided to build my own for two reasons. First I really needed a way to sharpen end mills and other tooling around the sharp, on many occasions I would be down to one end mill and that of questionable status. Meanwhile the drawer of dull and damaged tools was beginning to fill. My other reason was that I was trying to learn something about machining. I took this up as a hobby about five years ago and found that I enjoyed it immensely. But I soon learned that I knew very little about the subject and it was much more complex than it appeared on the surface. I viewed building a cutter grinder as a sort of "complete course in milling and turning". A project such as this can be a very valuable learning experience. I set aside a leisurely schedule, the idea was that learning was the prime motive. I scrapped a lot of parts, but that is part of the learning process. I spent hours reading various blog sites to learn from the experience of others.
The following photo shows my unit which is based on the original design published by Derek Brooks back in the early 90's. I took advantage of recent technology improvements and after building the original unit I started a redesign to use these improvements. The result was very satisfying, my unit gets a lot of use. Sharpening end mills in itself is a complex subject but very doable by the hobbyist.
Photo #1 - A cutter grinder based upon the original design by Derek Brooks and published in Model Engineering in the early 90's.
So, look at all of your options. There are lots of pieces in this grinder but each individual piece is not that complicated. All of the details are available in Home Shop Machinist.
Jim
Buying a used Darex or similar type unit and reworking it to meet your needs is a good approach. But why not build your own? I had this same dilemma a few years back and after researching the subject decided to build my own for two reasons. First I really needed a way to sharpen end mills and other tooling around the sharp, on many occasions I would be down to one end mill and that of questionable status. Meanwhile the drawer of dull and damaged tools was beginning to fill. My other reason was that I was trying to learn something about machining. I took this up as a hobby about five years ago and found that I enjoyed it immensely. But I soon learned that I knew very little about the subject and it was much more complex than it appeared on the surface. I viewed building a cutter grinder as a sort of "complete course in milling and turning". A project such as this can be a very valuable learning experience. I set aside a leisurely schedule, the idea was that learning was the prime motive. I scrapped a lot of parts, but that is part of the learning process. I spent hours reading various blog sites to learn from the experience of others.
The following photo shows my unit which is based on the original design published by Derek Brooks back in the early 90's. I took advantage of recent technology improvements and after building the original unit I started a redesign to use these improvements. The result was very satisfying, my unit gets a lot of use. Sharpening end mills in itself is a complex subject but very doable by the hobbyist.
Photo #1 - A cutter grinder based upon the original design by Derek Brooks and published in Model Engineering in the early 90's.
So, look at all of your options. There are lots of pieces in this grinder but each individual piece is not that complicated. All of the details are available in Home Shop Machinist.
Jim
- Joined
- Mar 6, 2013
- Messages
- 9
Hi Jim,
That is a very nice looking tool grinder. Would you mind explaining a bit about how it works and the features you use the most? I am also considering a tool grinder build and I am currently trying to understand what features I even want to consider.
Thanks for sharing.
That is a very nice looking tool grinder. Would you mind explaining a bit about how it works and the features you use the most? I am also considering a tool grinder build and I am currently trying to understand what features I even want to consider.
Thanks for sharing.
- Joined
- Jan 21, 2013
- Messages
- 865
This made me curious about the original design, and the first thing I ran into was a youtube of Jim's very machine!
http://www.youtube.com/watch?v=8ns7I6jwyIw
http://www.youtube.com/watch?v=8ns7I6jwyIw
- Joined
- Aug 14, 2011
- Messages
- 101
Hi crcarlson, you ask a very good question. There are a short list of features that make the difference between a machine that will perform some functions but not quite all that you would desire. Off the top of my head I would list the following areas of functionality that need to be considered:
1. Your tool head must have a 3 axis ability, the vertical axis needs to rotate 360 degrees to allow sharpening both sides of the same tool without removing the tool. The horizontal axis should have enough movement to provide secondary relief on the tools you are sharpening, usually something in 20 degree range will take care of that needs. The original design would only go to about 10 degrees. The tool axis of course needs to go 360 degrees so that can deal with four flute end mills, slot drills, etc. This axis contains the collet.
2. The table that holds the tool head is the work platform and must be able to move from side-to-side and in and out accurately with minimal friction. For the modified version that was my second effort I used linear bearings for the side-to-side portion and plain steel bearings for the in and out part. The side-to-side motion is where most of the work is done. The in-feed is applied in small doses, a thousand or two usually.
3. Being able to move the wheel from side-to-side is important, it is either that approach or a very long and heavy table. You need a work envelope that is easily adjusted. The first iteration of this had a fixed grinding head which was very limited in use. I tried many different approaches moving it (addition sets of locking holes etc) but none were satisfactory. The sliding arrangement that runs on sealed bearings and locks with a cam was vast improvement.
4. The grinding head needs to run at about 4-5 thousand RPM using a 3 or 3.5" wheel. To do this without vibration means you needs good bearing assembly, a good motor and drive system, and a balanced wheel. The motor needs to be reversible so that you have the ability to grind with or against the tool as needed.
5. Derek Brooks depended on stone wheels for his version, I much prefer composite wheels (diamond or CBN). Dressing and maintaining a rack of stone wheels would be a chore for a hobbyist such a me. There are operations where very small high speed wheels can be used but these wheels cover 90+ percent of my needs.
6. Limitations are important. You will not be able to retain the center cutting ability of end mills. I usually gash the end mill to relieve that center cutting portion if it has one and move on. In a hobby shop there are lots of ways around center cutting end mills. Sharpening mills less than 3/8" is not practical, fortunately these are least expensive. I find that I use a lot of larger end mills since most of the work is step milling of one type or another. 3/4 and 1" end mills are my work horses. I bought some used and abused good quality (Nigara, Putnam, etc) on eBay and resharpened them with excellent results.
That's my two minutes dump on what I feel is important. I applaud your interest in building a grinder of what ever design (Brooks, Quorn, etc), it is a very good way to sharpen your skills and end up with a very useful tool.
Jim
1. Your tool head must have a 3 axis ability, the vertical axis needs to rotate 360 degrees to allow sharpening both sides of the same tool without removing the tool. The horizontal axis should have enough movement to provide secondary relief on the tools you are sharpening, usually something in 20 degree range will take care of that needs. The original design would only go to about 10 degrees. The tool axis of course needs to go 360 degrees so that can deal with four flute end mills, slot drills, etc. This axis contains the collet.
2. The table that holds the tool head is the work platform and must be able to move from side-to-side and in and out accurately with minimal friction. For the modified version that was my second effort I used linear bearings for the side-to-side portion and plain steel bearings for the in and out part. The side-to-side motion is where most of the work is done. The in-feed is applied in small doses, a thousand or two usually.
3. Being able to move the wheel from side-to-side is important, it is either that approach or a very long and heavy table. You need a work envelope that is easily adjusted. The first iteration of this had a fixed grinding head which was very limited in use. I tried many different approaches moving it (addition sets of locking holes etc) but none were satisfactory. The sliding arrangement that runs on sealed bearings and locks with a cam was vast improvement.
4. The grinding head needs to run at about 4-5 thousand RPM using a 3 or 3.5" wheel. To do this without vibration means you needs good bearing assembly, a good motor and drive system, and a balanced wheel. The motor needs to be reversible so that you have the ability to grind with or against the tool as needed.
5. Derek Brooks depended on stone wheels for his version, I much prefer composite wheels (diamond or CBN). Dressing and maintaining a rack of stone wheels would be a chore for a hobbyist such a me. There are operations where very small high speed wheels can be used but these wheels cover 90+ percent of my needs.
6. Limitations are important. You will not be able to retain the center cutting ability of end mills. I usually gash the end mill to relieve that center cutting portion if it has one and move on. In a hobby shop there are lots of ways around center cutting end mills. Sharpening mills less than 3/8" is not practical, fortunately these are least expensive. I find that I use a lot of larger end mills since most of the work is step milling of one type or another. 3/4 and 1" end mills are my work horses. I bought some used and abused good quality (Nigara, Putnam, etc) on eBay and resharpened them with excellent results.
That's my two minutes dump on what I feel is important. I applaud your interest in building a grinder of what ever design (Brooks, Quorn, etc), it is a very good way to sharpen your skills and end up with a very useful tool.
Jim