[PaulRowntree]

That is very nice Don. It was a seriously large piece of wood that you started with!
When cutting the keyholes (clever!) did you worry about how the centre of mass would move with such a thick relief, which might have caused it to hang crooked?

[DonFrambach]

...When cutting the keyholes (clever!) did you worry about how the centre of mass would move with such a thick relief, which might have caused it to hang crooked?

Since there are two keyholes at each level, the plaque will be stable when hung by at least two screws or nails. The problem is making the two keyholes level with the pattern on the other side. I cut the keyholes first (with the router) then flipped the workpiece over to cut the relief. I'm still working out a reliable way to index the workpiece so that the keyholes are level after the flip.

Since the keyholes were cut by the router, they are exactly the same length and the distance between them is exactly as specified. This should make mounting the plaques pretty easy with a ruler and a level.

[piperpilot]

Don, this is very interesting...how did you undercut the long slide part of the keyhole? I assume those brass bolts slide into each keyhole right? Did you use a special bit for cutting this?

[DonFrambach]

Did you use a special bit for cutting this?

Here's some better pictures.

I first cut a 1/4" slot with a straight bit. I then used a "keyhole" bit to form the undercut. I got the bit from Woodcraft. The t-bolts too (Buy T-Bolts 1 4-20 x 1-3 4 at Woodcraft). It's important to use a t-bolt because a regular bolt would spin as you tried to tighten the nut holding it to the mdf mount.

I cut the t-bolts to length. The keyholes themselves are cut 3/8" into the workpiece.

[CarveOne]

The keyhole cutter should be able to drill its own hole, then move sideways, retract, then raise up. The cutter has cutting edges on the face and edges. I've been doing them on my milling machine by hand, but Vcarve Pro has a "Gadget" for doing that I'll have to try one day.

CarveOne

[DonFrambach]

The keyhole cutter should be able to drill its own hole, then move sideways, retract, then raise up. ...

I thought so too when I bought the bit. However, when I look at the bit, while there are cutting surfaces on the bottom, I don't see a center cutting capacity. Although I'm probably wrong and the bit can plunge, I thought it was safer to cut a clearance groove first with a 1/4" spiral bit.

I wrote a small program that allows me to specify the number, spacing, orientation, depth, and lengths of the keyhole slots. The program creates one gcode file for the spiral bit and another for the keyhole bit. I suppose I could try running just the keyhole file when I'm feeling brave.

Here's a photo of the bottom of my keyhole bit:

[PaulRowntree]

Could you ramp in at just enough of an angle to engage the edges? It just removes one tool change...
Being willing and able to do the manual g-code makes a world of difference.

[CarveOne]

If you were plunging into aluminum it would not work, but try it in MDF or regular wood and I think it will work ok, because that little bit of wood fibers in the center will find their way out if the plunge rate is relatively slow, like 10 to 15 ipm.

If you ramp it in as Paul recommends, that will insure that it cuts vertically and the ramp angle only needs to be enough to slide across the little gap in the cutting edges.

If you have Vcarve Pro try the key hole Gadget and see how it works with the cutter you have. It does not appear to have the ramping built in. I just tried it. Draw a circle where you want the key hole to be centered as a starting point. You can change the entry hole size and slot length from a list. Choose a "dummy" end mill from the VCP tool table to use for generating the tool path. Click OK and it will add vectors to the CAD drawing for the Preview screen to display it. Looks simple enough to use.

CarveOne

[ger21]

If you have Vcarve Pro try the key hole Gadget and see how it works with the cutter you have. It does not appear to have the ramping built in. I just tried it. Draw a circle where you want the key hole to be centered as a starting point. You can change the entry hole size and slot length from a list. Choose a "dummy" end mill from the VCP tool table to use for generating the tool path. Click OK and it will add vectors to the CAD drawing for the Preview screen to display it. Looks simple enough to use.

I didn't try the gadget, but you can also just draw a polyline, say 1"up and 1" back down. Select the keyhole bit as your tool, and create a profile pass on the line.

You can use the same polyline to do a roughing pass with a smaller straight bit first if you want.

[jjobezo]

Hanging Slot Router Bits - Rockler Woodworking Tools

[DonFrambach]

Scored a couple of real nice Parker Daedal linear actuators. Both with precision ground ballscrews. One 6 inches wide with 14" of travel, the other 100mm wide with 150mm of travel. Thought I'd incorporate them into my small router. Here's some photos:

[DonFrambach]

Wanted to mount the larger of the two actuators on my fixed gantry (what I call the "x" axis). Naturally the holes in the actuator don't line up with the 8020 extrusion so I had to make a mounting plate. Made the plate from a piece of 6" x 22" x .75" MIC 6 aluminum. Rather than simply tap 1/4 x 20 holes into the aluminum, I used steel weld nuts. I milled slots into the back of the mounting plate so that the weld nuts would not turn and would not interfere with the back surface of the plate. The weld nuts are shown in the second and third photos. The fourth photo shows the front of the mounting plate with relief cuts for the 5/16 x 16 button head cap screws. The fifth and sixth photos show the front and back of the plate before I mounted it on my router. The 1/4 x 20 screws seen in the fifth photo were used temporarily to hold the weld nuts in place as the plate was mounted.

[DonFrambach]

Mounted the plate and the 6" linear actuator to the router. First photo shows the frame of the router. The second shows the mounting plate attached. The third shows the linear actuator attached to the mounting plate. The fourth photo shows the actuator mounted on the router with it way protectors installed.

[DonFrambach]

Wanted to mount the linear actuators face to face in order to maximize useful "z" axis travel. This required another adapter plate shown in the first photo. The second photos shows the plate attached to the 100mm wide actuator. The third photo shows the actuator mounted on the router.

[DonFrambach]

Made a third mounting plate to accept the spindle mount. Used weld nuts again so that I would have screws into steel rather than simply threaded aluminum. The outer two screw holes are threaded into aluminum for alignment. The last photo shows that the holes in the actuator for alignment pins were closed with electrical tape. These holes were in recesses so that the tape did not interfere with the vertical alignment.

[DonFrambach]

Didn't like that I only had 6 tapped holes in the aluminum base to attach the spindle plate. The side of the actuator is slotted so I made two clips to hold the plate onto the actuator from the edges. I used weld nuts again. Note the ridge on the clip shown in photo "4". The last photo shows a clip attached to the left side of the actuator.

[DonFrambach]

The first photo shows the stepper motors reinstalled as well as the spindle mount that I made some time ago for the Kress spindle attached to the router. The last two photos show the Kress spindle installed and 110v and 12v power sources attached to a wooden bracket screwed to the top of the 100mm linear actuator. Still need to install the limit switches.

[DeadTom]

You have been a busy little beaver, nice scoring those linear actuators.
The build looks great, thanks for sharing your progress.

Tom

[RomanLini]

Very impressive new linear slides! And I thought your machine was already very nicely finished, but you can't argue with precision brand-name slides and ground ballscrews that's for sure.

Are you using a router now for your spindle? If you like I will talk with Val about a SuperPID, he might be willing to supply you with a free one since your machine would be a very nice showcase for it, and your machine is sturdy for aluminium cutting etc, which means you would get good benefits from the router+SuperPID.

[DonFrambach]

...but you can't argue with precision brand-name slides and ground ballscrews that's for sure.

Actually, I'm having second thoughts.

I was excited to get these actuators because I thought that I'll be able to run my machine faster which may be significant because I've done runs as long as 20 hours. Now that I have these expensive (and essentially irreplaceable) actuators, I'm going to use them VERY carefully. For example, after I've assembled the machine, I've become concerned that the actuators have not been lubricated for a while. Consequently, this weekend, instead of using the router to work on a project, I'm going to disassemble the machine and lubricate everything.

One could argue, then, that it's better for a DYI machine to be made of relatively inexpensive "skate-board" bearings and ACME threaded rod than expensive irreplaceable parts because the former machine will be used much more than the later!

Roman - thanks for the kind offer regarding the SuperPID. For now, though, I'm going to concentrate on cutting wood with the Kress spindle. (Totally afraid I might break something expensive cutting metal).