Engraver Spindle Collet and/or replacement

In the ongoing effort to get my old Dahlgren/Suregrave Engraver 400EZ up and running with modern electronics, I am trying to figure out what to do about the engraving spindle. I have a couple questions I'm hoping someone can help me with because I'm at a loss on where to begin my search.

The current engraving spindle is clamped in place on a carriage on the X-axis, and the carriage is built in a way that it would need a lot of modifications which are beyond my ability at this point. I've considered adapting this to take a new router spindle but given the low profile of the engraving spindle, this isn't really going to work.

The existing spindle I have is a top-load engraving spindle (I might not have the terminology correct here). It is driven by a belt from a separate motor. What are these types of systems called? I'm having trouble search when I don't know what to call it.

I would like to adapt the spindle to have a collet to accept router bits. Does anyone know how this might be achieved aside from replacing the spindle. For example, do they make collet adapters for rotary spindles?

Whatever help, advice, or terminology you can offer is much appreciated.

For reference, here is a photo of the machine shortly after I received it:

I think I know what he's talking about. One of our Gerber routers came with a top load engraver head. The engraver bits are about 6" long and drop through the spindle from the top and I believe just kind of float in the spindle and are spun by a belt. I don't think there is much if any provision for applying down pressure. (I'm really not sure, as we have never tried to used it in 18 years I've worked here.)

From that photo, it does look like it would be a challenge to retro fit it for a router spindle.

Some closer photos of the spindle mounting area and the Z-axis mechanism would be helpful.

The engraver bit can be seen here:

It is 150mm long and 6mm in diameter before the v-ish bit at the end. It feeds into the belt-driven spindle:

which is clamped (25mm shaft diameter) to the z-axis slide:


Upon re-investigating the spindle, I don't think it drops in from the top because the cutter wouldn't fit through the 6mm bore in the spindle. However, it is tightened at the top with a setscrew.

I don't have any closer photos of the z-axis carriage on hand, but I'll try to get them tonight to further illustrate the situation.

I have a theory on how I can convert it to a collet to hold end mills, but I'm not sure it will work. I'm looking to find a length of 6mm steel rod to feed through the spindle and secure in place with the set screw. Then, I'll attach something similar to this (with the correct 6mm ID). Thoughts on that plan?

I've been searching for C6 ER11 Collet Shanks and I've been finding items similar to what you found. The issue is that the 100L is 100mm length and if I feed the current cutter into the spindle, it really needs the full 150mm. It seems the longest length I can find for a C6 is the 100mm. This is why I'm leaning towards putting one together right now.

If anyone knows of a supplier that has a 150mm C6, I'd love to hear about it!

I think the tools would have to go in and out of the top. All the engraver bits like this I've seen are straight (1/4") diameter the full length including the tip. Also there is no provision to raise the spindle high enough to be able to pull a tool that long out of the bottom on your machine.
I'm not sure that that one little profile way your engraver head rides on will be tough enough for routing either.

You are probably right, I haven't futz with the bits too much while the spindle is attached to the machine.

The machine was originally built as an engraver and I understand that I might be asking much of it by trying to route with it. Given all the complications I'm encountering with it, I'm thinking it might be easiest to get it set up as an engraver and use it as such. Once I have it working that way, maybe then I can explore some of the bits on this page: bitsbits.com/index.php?main_page=index&cPath=4_47 . I do see some options on that page which are end mills. Buying one of those to see what the machine can do in its original configuration would definitely be cheaper than trying to retrofit a system not intended for the machine.

I've floated the idea with the wife, because this was such a cheap CNC acquisition, that this is where I learn and once I've outgrown it I can consider what is next. She seems to be on board with that, mostly because I talk through these "headaches" with her and I think she assumes if everything worked fine she wouldn't have to hear about it

If anyone has any creative solutions other than what I mentioned above, I'm all ears.

Here is a copy of the documentation for the engraving head option on our routers. It looks like the actual engraving spindle and it's operation would be very similar to what you have. It might be helpful if you don't have any reference material.

Todd, yes! This is very helpful. One of my biggest frustrations with the Dahlgren/Suregrave 400EZ is that there is no information available for it online. Well, there is one guy on eBay selling an old manual for $50 but he doesn't even have one for my specific system.

This will help me understand the spindle a bit better and maybe operate it safely within its limits.