key hole maker help

[myshop1044]

attached is a mpc I picked up some time ago. based on the 2 hey hole ptns the direction of the cut is
bottom to top and top to bottom, if I'm right. I need one from right to left and
left to right. I have project that is 40" in length and I want to put a key hole on the left
side along the length.
any help be great. If anybody has the answer, please attach them to the attachment.

Perry B.

[bergerud]

If my memory serves me, the bit path routine starts on the path and follows the path as it was drawn in Designer. If you draw from left to right, the machine will cut from left to right. I have, in the past, had to redraw the same curve just to change the starting and ending points. (I am not sure about closed curves, the start and end point info may be lost.)

[myshop1044]

It appears after I looked at it for a while, there 2 connected lines on top of each other. the first plunges the bit down
travels a 1/2" distance, the the second returns on top to the start point and brings up the bit. So the direction of travel is from
the big circle to the little circle and returns back to the start point and lifts the bit.
I will try this test tomorrow and see, unless the person that created it first has the answer.

Perry B.

[fwharris]

Perry,

I think it was Cavejerry that posted the pocket cut. Is it possible to just do this on your router table?

[bergerud]

I do not think the outlines make sense. As you say, the lines are a double path going and coming back. The bit will start at one of the end points, follow the path and stop at the other end point where it started. This is inconsistent with the keyhole outlines. Surely the bit plunges in and out at the beginning and end of the path and so the keyhole hole is at the start-end points. The outlines look like they should be switched.

[Dan-Woodman]

If your using a keyhole bit you only need one line going the length of your slot and returning to the starting position. Years ago when I did this , I had to experiment with the depth. I think it was about 5/16" deep. I beleive at the time I was telling the machine to use the 3/8" bit. This was before you could tell it to go full depth. Any deeper than that and it would make several passes. Your line coming back may have to be a few thousands offsetfrom the first.

[Capt Bruce]

This might help clarify the technique of cutting a keyhole hanger slot. This a back side view from an MPC that places a horizontal key hole centered on a carved plaque. It uses a 3/8" dia keyhole cutter bit which the CW thinks is a 3/8" straight bit plunged just over 3/8" deep to leave two strong edges on the cutout. The yellow line is a connected line series from the left to the right and then back again to the starting point.

The bit enters and travels from left to right on the keypad side edge, reverses and cuts back to the start point and retracts. I made the connected return leg just a hair off the first path and again stopped it just a hair short of the start point. This makes it slightly larger to ease getting a full 3/8" dia screw head on the wall into the slot for hanging.

60301

I added the dashed line circle just for my own reference to remind me which side will be the plunge and retract point.

[myshop1044]

The results are in, thanks Bruce I did move my second line over a tad and every thing went perfect.
The 2 on the right was the original and 2 on the left is my new ones.

Perry B.

[Rob Mulgrew]

Really interesting. I just bought a keyhole bit and didnt even think about having the CW cut out the slot. How do you keep the bit from pulling out at the end of the cut leaving 2 holes? To clarify, how do you get the CW to cut in and then retract back to the starting position before lifting out? Thanks
Rob

[myshop1044]

Fellow Capt. Bruce instructions, it now use me explaning it again his is right on the mark.

Perry B.

[jmoriearty]

I do it the same way as Capt Bruce, make a slot instead of a keyhole, but I do it on the router table. I just set stops on both sides and guide it across the fence. If it's an odd shape or if it's too thin after the carve to put a keyhole slot in it, I use a long fine tooth saw-tooth hanger and epoxy it on. Always good to be versatile. :-)

[myshop1044]

here is mpc with the 4 keyhole slots ready to go.

Perry B.

[Rob Mulgrew]

Fellow Capt. Bruce instructions, it now use me explaning it again his is right on the mark.

Perry B.
I did read his post many times but still did not understand how to do this. I am new here. My apologies
Rob

[myshop1044]

That's ok, it took me a while to understand it too.
first you use the connected line tool, you will need 2 line segments
connected to each other as in the attachment.
You draw a line segment from right to left, then you draw the second line segment back to
near the starting point. You end the second segment by doing a right click on the mouse.
I did that and left the 2 line segments apart from each other for you to see.
With the 2 line segs. highlighted, you assign a bit using the 3/8" straight cut bit, depth of 1/4", then
You see a long oval. The hey hole bit will plunge down 1/4" at the start of the first line seg.
travel to the left and return back to the end of the 2nd line seg. near the start point and come up out of the hole.
Note when the machine ask you for to insert the straight cut bit you insert the 3/8" keyhole bit instead.
I hope this helps you better the procedure.

Perry B.

[Rob Mulgrew]

That helps alot. Thank you. I appreciate it. I am going to try this tomorrow or tuesday. It will save me about $1.50 on every sign because I have been buying keyhole hangers and screwing them to the back.
Rob

[CarverJerry]

FWHarris was correct about my posting in an earlier thread. I can cut a key hole in less than 3 mins using this little jig. It's a no brainer if you have a router.

[myshop1044]

You are correct about using a router or router table, after the machine measured my board it took 7 sec. to cut the keyhole,
then ask me to flip the board. To each his own.

Perry B.

[RMarkey]

I advise against this method -- you're guessing how the machine will behave. The fact is the machine optimizes various movements and could do something unexpected which could damage your machine or project. This project may move completely different in older or newer versions of the software. What happens if you get a cut motor error, close cover, card removed, y stall, or any other type of error?

[fwharris]

FWHarris was correct about my posting in an earlier thread. I can cut a key hole in less than 3 mins using this little jig. It's a no brainer if you have a router.

From the woodworker guild... https://www.wwgoa.com/articles/one-great-tip/using-a-keyhole-bit/

[Dan-Woodman]

It would help if we knew the feed rates for the different bits. Also you have to watch how deep you can go without it making two passes. The 3/8" cutting diameter of my keyhole bit is 1/4" deep , so I have to go at least 5/16" deep to make a keyhole. You may not want to try that in very hardwood.
Does anyone know , is there a differentance in the feed rates for 1/8", 1/4" and 3/8" bits?

[badbert]

AL has a trick for doing what he calls "Locking it in low gear".