View Full Version : Cheap Cam Bolt

Jimmy Southern
07-01-2005, 11:06 AM
Hello everyone, I am verrrrry new to the CNC hobby but I am very impressed with the knowledge that is available on this forum. I hope to soon join you in being able to say that I have my own CNC machine. Thanks for sharing your wealth of knowledge with a novice.

Now a bit of history, I am a sign maker by trade and a tinkerer and welder by choice. I am planning on building a 3'x4' usable area router for my sign business. I do alot of carved signs for the local area, and have simply run out of hours in the day to keep up with demand.

Now to the question, Vacpress has a thread on the wisecarver guide bearings and it seems that the main reason that most people are giving as a reason why it will be difficult is the cam bolts are difficult to produce. Well, I had this idea. take a short piece of crs rod (whatever length the thickness of your bearing is),drill the center hole a bit off center in a drill press. Then drill the side of the rod as if yo were going to put in a set screw. Then simply slip the new made cam over the shank of the bolt put a very quick spot weld in the hole you made for the set screw. Even if you are a sloppy welder 10 mins with a file and you have a cam bolt, viola, taa daa, shazam.

Let me know what you think of the idea.
Thanks Jimmy

PS how do you post the little smily faces

07-01-2005, 11:48 AM
: ) without the space = :)

07-01-2005, 01:09 PM
I like this idea a lot, the only problem I see is getting the hole just right.

07-01-2005, 01:13 PM
Also that's not really a cam.....in the sense that you can't control the ramp rate.

07-01-2005, 01:29 PM
I don't know what constitutes a true cam. What is a true cam?

It may not be a true cam, but if not, then I doubt that Bishop-Wisecarver uses a true cam for its adjuster either, since the since the cam surface is the bearing mount surface.

The ramp up is controlled by the diameter of the bolt, the diameter of the bearing surface and the distance between their two centers. If you can drill accurately, you would have pretty good control over the "rate of ramp".


Jimmy Southern
07-01-2005, 01:42 PM
1st the size issue.

I would pick the closest size rod to the ID of my bearing, maybe a little big, then I would figure how many I needed then simply chuck it in the drill press(cheap mans metal lathe). With a little bit of patience and a good file you can do a reasonable fit. if your talking about the shank of the bolt the size should be easily accessable from any hardware.

2nd the ramp rate.

You would most certainly want to do some pre assembly to determine the amount of movement you will need the cam to make. Then you cold quite easily offset the cam hole and add just a little bit for future adjustment. I really don't think that the ramp rate at the size we are talking about would really matter as long as the cam was capable of going far enough to make the bearing touch the guide rail. Also this would probably require a clamping jig for your driil press to make sure the hole is located correctly but one thing I have noticed about you guys(and girls) is that you are very resourceful when it saves some clams$$$. Thanks Jimmy:)

07-01-2005, 01:59 PM
It's an eccentric. I think that's the more accurate term - same function for this application.


Jimmy Southern
07-01-2005, 03:58 PM
Thanks for the correction I could not think of the term eccentric :)

Jimmy Southern
07-01-2005, 06:11 PM
I just re-read my original post and noticed I had left something out. For those who have not read the Vacpress post he was not using wisecarver guides, he is making his own with skate bearings and flat plate. I am not sure what material or edge profile he was going to use. If my memory serves me the posters eventually found the bearings pre made in China. I hope that clears up some questions that might have come up.

PS finally got a decent deal on a digital camera on ebay so hopefully soon I will start a thread on the building of my machine. and I will have lots of electrical questions(complete virgin on electronics). Thanks everyone.