Cody arm questions - alot of them!

[David Delaney]

Cody, I am working on the arm and run into more than one hole in the road.
1) found a 27/32 drill bit, but it will not work because my drill press shakes with such a force when drilling (even with oil), that I cannot use it - I have to drill a hole with a circular saw first that is smaller and then use the 27/32 to make it slightly bigger - BUT when I try to place the bearings in the hole and hammer with wood, the don't go in evenly.  Tilted etc.

2)  I tried to knock them in as hard as I could, even if they were on a bit of an angle - they went in a little and tightened the bearing so much, it no longer spins.  Not sure what to do here.  ANy ideas?

3) Decided to try and find an aluminum reamer (not an easy task) or a metal bit for a router to try and widen the hole (I don't think I remember seeing you suggest this).  What did you do to give the holes a little extra space for the bearings?!

Alot of frustrations without even starting this thing!   Any helpful hints?

[Cody Deegan]

Sorry to hear about your problems, David.  Down in my arms forum I had posted a tip for avoiding some bearing mounting issues.  Knowing what I know now, I would approach the bearings in a completely different manner.  But at the time of the plans writing, I simply documented what I did.  You could order some new aluminum from <url>http://www.onlinemetals.com</url> in the flatbar rather than the square tubing and drill the holes to the depth of the bearing's width.  Even if the hole is not precise and there is a bit of play with the bearing, I've found that once the arm is under load, all the bearings will find a seat and not move or cause any noticeable disturbance to the action of the arm.  The forces involved keep them in place and provide a suitable response.  Another option is to use different bearings that have a standard size OD.  I was of course trying to save money at the time and found skate bearings readily available and inexpensive.  These of course forced the need for a wacky-sized drill bit.  I never had problems getting my bearings in though.  I remember having to run the drill press at an extremely slow speed.

[David Delaney]

Well since I have 24 abec skateboard bearings (like you), I am going to use them because it beat buying something new - and trying to find something available.  I found a cylindrical filing bit at Home Depot - it seems to work ok, but I have to be careful not to shave too much off, then the bearing will fall right through.  Still pecking away at it - and yes, there are some things that I would do differently myself next time ,but I guess you live and learn.