New Block Tooling Fixture

[Big Dirt]

Looking to build a new body fixture kinda like the Pro-Body tool (great piece) only make it 7.0 long and able to drill all 4 axel holes with out unclamping the block. I was wondering how thick i should make it? any thoughts?

[RACER X]

Big Dirt;

When you ask how thick should you make it, are you refering to to the material you would need for the base stock?

When we designed the Pro Body tool, the first task was for the tool to support the #44 drill bit and prevent deflection, even with the best of drill presses, the bit is still the weakest link.

Secondly, the tool had to establish parallel axle holes or slots. When drilling axle holes, they must meet in the center when drilling from both sides. Accuracy is a must!

Third, the cut-out in the base stock, just any old piece of channel would not do, the cut-out along with the holes and reference marks are all done on a CNC mill for the best accuracy, this would be hard to duplicate at home.

What is your thought on a long one that you do not have to move?

We have had tremendous sucess in the alighnment process by just sliding the tool to the desired position,, maybe you have a better idea, we looked at a one piece tool, but it got cost prohibitive.

P.M. me if you like, maybe I can help.

See ya

Racer X

[Big Dirt]

Racer, was thinking of useing 6061 bar stock, clamped in the mill to do the mill the slot, then in the rotorey table to drill the axel holes. Just thoughts and play time ya know.

[Jewel]

What exactly is the Pro Body Tool? What does it do? And if it works how do I get one?

[RACER X]

A Pro Body Tool is a drill guide that allows the builder to re-drill existing axle slots or make new axle holes with greater accuracy.

The Pro Body Tool will keep a small # 44 drill bit from wandering even in a drill press and when combined with a Pro Axle Press your alignment could not be any easier or accurate.

www.maximum-velocity.com has them.

See ya

Racer X

[Jewel]

Got it. Use an aluminum block to keep the #44 drill walking off. I would think that if drill the whole pretty deep it would still start to walk off center.

Would about .250 thick piece of 6061 Al clamped on top of your car body and then drilled striaght into work well as a guide? The aluminum would guide the drill, however the side cutting surface of the drill still may bend make the Al .250 hole go out of round.

The key idea for getting LBW alignment here is that to start with supper straight holes helps a great deal when it comes to getting the alignment right.

[RACER X]

Super straight holes are the key to the Pro Body Tool.

The tool is CNC machined to be square to the centerline of your base block. When you locate it and clamp it to your block, it will ensure that the axles are perpendicular to the CL of the car and that all axle holes are the same height from the botttom of the body block every time. When drilling new holes, the holes will meet perfectly in the center each time and look as if they were drilled as one, this is almost impossible without some type of assistance when using a #44.

We have found that if the axle holes are straight [Pro Body] and the axles are straight [Pro Axle] that tha car will almost allways go straight. Any time we start to bend or twist axles to correct alignment we stray away from that natural state that is where the least amount of friction is.

It is also pretty amazing how tweeked kit axles are.

You can fight mis-alighned slots or holes and tweeked axles or you can resolve the problem.

[Stan Pope]

"Rolling Straight" is the first plateau of alignment. Good, but not good enough.

[RACER X]

"Rolling Straight" is the first plateau of alignment. Good, but not good enough.

Your turn, the "Second plateau is?"

[Stan Pope]

Oh-oh ... I've gotten terribly off-thread and off-topic with latest comment. I'll try to find an appropriate topic in which to continue the "plateau" discussion. I surely don't want to be chastised again by The Moderator!

[Stan Pope]

Oh-oh ... I've gotten terribly off-thread and off-topic with latest comment. I'll try to find an appropriate topic in which to continue the "plateau" discussion. I surely don't want to be chastised again by The Moderator!

Oh, what the hey. I'll brave The Moderator's slings and arrows.

Second Plateau of Alignment:

Here's the problem ... a car can roll straight for a considerable distance and yet have a loss-producing toe-in or toe-out in the axles. Consider symmetrical toe-in. As the car rolls forward, the wheels migrate toward the car body. When they finally reach the car's body, the hubs pinch the body and produce elevated braking torque. Sooner or later, something has to give ... wheels skid or, more likely, get twisted slightly on the axle so as allow them to continue to turn, again at elevated braking torque.

This is especially critical when it happens on the rear axles which are likely to be carrying 80% of the car's weight, but are least apt to be properly aligned by usual techniques.

Even before the wheels reach the axle extremes, tho, there appears to be an elevated wheel-axle friction, possibly from the fact that the wheel must both slide on the circumference of the axle shaft, but slide along its length as well.

The alignment method detailed in my book identifies the existance of this misalignment and provides a convergent procedure for removing the misalignment. When complete, the car seems to breath an almost audible sigh of relief.

[Stan Pope]

Well, I shouldn't try to compose for posting and read bedtime stories to grandson at the same time.

I properly included the fore-aft axle alignment error, but omitted the up-down errors. These, too, are addressed and resolved by the referenced procedure.

Note that there are two degrees of freedom in each axle. The referenced procedure can address these individually or in concert in a convergent fashion.

[RACER X]

You will "NEVER" resolve toe in or toe out without a straight axle. Most kit axles leave a bit to be desired, the best are still .010" out.

In the case of a PWD racer we are looking at axles to CL. In an automotive application we refer to "Thrust Angle" maybe we have a
"Coast Angle" If the axles are not perpendicular to the CL in both directions, now the only way we have to align the car is to "Tweek the axles" this is now working against the proper mechanics and any posibility of minimum friction.

If the holes are straight to the center line of the block and all the same height from the bottom of the block, along w/ straight axles"Pressed" then the car is in it's most natural, mechanicaly correct state. At this point, alignment adjustments should be none or minimal.

[Stan Pope]

If the holes are straight to the center line of the block and all the same height from the bottom of the block, along w/ straight axles"Pressed" then the car is in it's most natural, mechanicaly correct state. At this point, alignment adjustments should be none or minimal.

Big "ifs".

Wood is not homogeneous.

The result is a tendency to deflect the drill slightly as the hole deepens.
A further result is that wood compression resulting from pressing the nail into the hole tends to deflect the nail slightly.

Murphy's Law dictates that these errors do not (or, at least, almost never) cancel.

Thus, you can almost always improve performance by reestablishing correct axle orientation. My experience assisting skilled machinists seems to substantiate these conclusions.

The trick for most of us is to have gages of sufficient sensitivity to tell us what to do to improve the alignment for each wheel. Actually, such "gages" are built into the car, but most folks don't recognize their presence nor how to use them.

This is where the alignment method in my book comes in. If you haven't read it, do so, on me. (I ask a donation to my council's "Friends of Scouting" campaign for use of the book, but that is all between the reader and my council. And, the council doesn't know until the reader sends a donation. So, have at it.) Whether I "invented" it or "reinvented" it, I don't know for sure. I did a thorough review of the literature at initial publication and turned up nothing akin, but, who knows if anyone else "got there first" and declined to share. Either way, it works ... very well.

I completely agree about bent axles ... each axle has two degrees of potential error. Addressing the error by bending the axle and rotating it is "cut and try" without direction. There is a much better way! The "bend" addresses one of the degrees of freedom in a very crude fashion; rotation addresses the other. It is much better to attack both degrees of freedom in a vernier manner that does not bend the axle.

I don't know if I a "preaching to the choir" or not ... but, so far, I've gotten little sense that these alignment distinctions are understood.

[RACER X]

Oh believe me Stan, I understand alignment very well, from automobiles to P.W.D. cars.

I just think you are using "Old School" techniques to compensate for inaccurate components and workmanship.

I have seen, heard and read so many forms of tweeking, shimming and axle twisting that I just chuckle now.

The best foundation for proper alighnment is and allways will be accurate components assembled square to the centerline of the car.

I am getting little sence that you understand the improvements that can be made with the Pro Tools.