Swifty
Well-Known Member
I have a cutter grinder, as well as square and hex collet blocks that take 5C collets. I have a fair range of 5C collets, but to use them the piece being held must be within a few thousands of an inch. This doesn't allow for odd diameters. I also have a 20mm shank ER20 collet holder and collets, although this only holds up to 13mm. I thought that it would be handy to be able to hold any odd size up to 13mm. So with this in mind, I set about making an adaptor to allow me to hold the ER collets in a 5c collet body.
Why didn't I just buy a 20mm 5C collet and grip the ER holder you ask, well, I thought that it would make a great short project.
I decided to detail my progress here in case anyone else decided to make one. Of course, the end could be made to suit any size ER collets that you have.
I have used a piece of Bohler M200, a plastic mould steel, as it is already 30 - 32Rc in its soft condition. Although I have used carbide tooling to machine it, except for drilling, you can use HSS but just watch the speed and feed.
Pic 1. First step was to drill out the middle, rough turn the outside and part off.
Pic 2. Next, rough turn the other end and rough turn the 5C taper.
Pic 3. Roughed blank.
Pic 4. Setting the topslide to match the 5C taper.
Pic5. Start to finish turn.
Pic 6. Screw cut large end.
Pic 7. Turn the piece around and screw cut the small end.
Why didn't I just buy a 20mm 5C collet and grip the ER holder you ask, well, I thought that it would make a great short project.
I decided to detail my progress here in case anyone else decided to make one. Of course, the end could be made to suit any size ER collets that you have.
I have used a piece of Bohler M200, a plastic mould steel, as it is already 30 - 32Rc in its soft condition. Although I have used carbide tooling to machine it, except for drilling, you can use HSS but just watch the speed and feed.
Pic 1. First step was to drill out the middle, rough turn the outside and part off.
Pic 2. Next, rough turn the other end and rough turn the 5C taper.
Pic 3. Roughed blank.
Pic 4. Setting the topslide to match the 5C taper.
Pic5. Start to finish turn.
Pic 6. Screw cut large end.
Pic 7. Turn the piece around and screw cut the small end.
