ER11 Adapter for the CT

[bergerud]

Addendum: I just had a thought. Here I am talking about the extra mass of an ER20 spindle and yet the same effect will be present using an ER11 adapter on a CT spindle, i.e. extra spinning mass on the flex shaft and cut motor. Of course any time I use the ER11 adapter I would be using small bits and by simple physics, the stresses would be smaller than using my Freud 1/2" shank, 1" diameter, 90° V-bit (one of my favorites for Centerline Text). So, though this may be a valid thought, I'm not sure how relevant to any machine damaging concerns it might be.

200k

The addition of the ER11 adapter is no big deal. It is not the mass that is so important, it is the rotational inertia. The rotational inertia is proportional to the mass, true, but also proportional to the radius squared. Mass out at a large radius is what is hard to spin up.

[bergerud]

Here is my latest attempt at an ER11 adapter. I made it from a $15 (plus shipping) ER11M extension. According to the picture, I thought I would only have to cut off the long shank. The extension, however, was not as pictured and I had to turn off some extra metal. (Beware of of this if you buy from China. Ask first if the product is as pictured before you buy.) Then I had to drill it out and file on some flats. The problem with this holder is that the acuracy of final result does depend on the original acuracy of the holder because the threaded part is 1/2" and cannot really be turned true.

This is really going to work well with the dust shoe. I really like the small diameter mini nut and wrench. (I have to make another window for just for it.)

http://www.ebay.ca/itm/160639939266?...84.m1497.l2649

[mtylerfl]

That is lookin' great, Dan.

[wlkjr]

What makes the ER11 better than a collet adapter? http://www.amazon.com/gp/product/B00...4R3RN9K64M5DA9

[Deolman]

I have seen that type of collet adapter slip.

[bergerud]

What makes the ER11 better than a collet adapter?

Those split adapters, as mentioned, do not hold well on carbide with only a split or two in them. They do not cover many sizes. Good luck finding a 3/16" one. If you do find a 1/8" one it will be so thick it will slip on carbide for sure. The ER system is one of the CNC industry standards for milling machines. They are simple, symmetric, and really work well.

What I am proposing here are removable adapters which stay on the bit. You tighten them on outside the machine and insert them like you would with a QC or pressed on adapter.

[wlkjr]

Gotcha. I see the need now, especially for the shanks smaller than 1/4

[dltccf]

Those split adapters, as mentioned, do not hold well on carbide with only a split or two in them. They do not cover many sizes. Good luck finding a 3/16" one. If you do find a 1/8" one it will be so thick it will slip on carbide for sure. The ER system is one of the CNC industry standards for milling machines. They are simple, symmetric, and really work well.

What I am proposing here are removable adapters which stay on the bit. You tighten them on outside the machine and insert them like you would with a QC or pressed on adapter.

Thanks, this helped me too. I have been following the conversation, but wasn't sure what was being accomplished. This made it clear.

dave

[chief2007]

CW-parts, the rock chuck home page carries adapters 1/2 to 1/8, 1/2-3/16, that work in the carvetight. I use them on one of my machines - no problems thus far and no slippage.

[bergerud]

That is a really good point Chief. Although not quite as versatile or as convenient as a set of ER adapters would be, those Rock adapters sound like they get the job done.
I really liked the original quick change idea with the QC adapters. These ER adapters could provide a slick quick change system. For those who carve a lot of multi-bit projects, it would be convenient. A single part in and out. No collars.