probox mods & adjustments

General Discussion
1

http://www.swaylocks.com/forum/gforum.cgi?post=342938;search_string=probox%20drill;#342938

Larry got me started on this with screw size.

Generalized instructions for grinding ProBox fin tabs and tapping a new screw:

Okay, needed to grind the fin tab and move the side screw on a probox rear set fin box.

You know grinding the tab so that you can either get more front or back placement, then

placing a side screw with a die & tap set.

In my case I have a quad , so I have 2 of the typical center fin (short board) fin boxes without insert that has side screws.

Heres what I found the side screws are 10-24

(you wont hardly find this anywhere else on the internet, Im almost 100% sure FCS is the same and maybe the others),

which means the thread size is 10 and there are 24 turns per inch

on the screw.

http://www.santabarbarasurfing.com/reviews/2006/04/fcs-replacement-screws.html

Screw:

10-24 x 5/16 Cup Point Set Screw, Stainless Steel, $0.13

Tool:

3/32″ Hex Head Allen Wrench

So you use the 10-24 tap that you can get from a SAE Die & Tap kit at Freight Harbour. Any SAE Kit will do.

On sale for me $9.99 up to around $30 and even more if you so desire.

Use a #25 drill bit for the final hole before using the 10-24 tap.

I used a smaller drill bit to initialize the hole, then went for the #25.

Now comes twisting the 10-24 tap.

I had huge problems with the handle that is supposed to clamp down the tap.

It was either too big…the rotating handle was BIGTIME in the way and constant equal pressure could not be applied.

OR , the smaller handle that came with the kit, was engineered so poorly that it would slip while turning the tap!

Mucho problemos here!!!

Finally, I went to Ace Hardware and was able to buy a really nice ‘T-Handle Tap Wrench’ made by Irwin/ Hanson

additional info: for tap sizes #0-1/4" and ‘Spring Tension Sliding Handle’ for $7.99

With this tool as a handle to hold the tap, it went smooth as silk!

I was twisting the tap while the board was on a glassing rack and no other body or board geometry involved.

Looks like this method could be finessed on the regular side fin boxes that use a ‘cant’ insert and side screws.

However, the top side margins on the regular side fin boxes are narrower, so this may be touch/go -problematic…but it looks do-able.

I understand probox has a longboard fin box without side screws but an inner set screw …for that box this method does not apply.

2

Well I can generally get .45" inch of fin adjustment from a probox

using a generic fin.

I have delved into grinding tabs and repositioning set screws to enhance the range of adjustment to about 1".

But that is somewhat of a big to-do!

Short of grinding on a new fin, I’ve been considering grinding

away on the insert rear stay portion to increase my adjustability to the rear. This will increase adjustability

from .45" to .65" inch and seems less costly than grinding away on a fin tab that would possibly prevent that fin from working in another board. Structurally it would seem that the insert would be okay, all things considered.

Anyone try grinding out a front or rear portion of a probox insert?

3

Finally cut out the rear stay on a probox insert:

Well I finally had a chance to get my newly made “HH-Overhead-DOH+” board a bit wet lately
in HH waves last week.
Sort of my 'all arounder HH on up ’ board.
Seems that my fins in the most rear position work well, but wasnt really sure
where the sweet spot is actually…whether more to the rear or I’m already there??.

So I put in my special made fins by Larry Allison(Fibre Glas Fins/ Probox) that
enable me to position my side fins a full 1/2" back further than otherwise normal.
These fins were put most forward , but still to the rear of the standard FCS most rearward
position.
With these special built Larry fins the board was a bit too stiff in their most forward position,
but functional in the HH waves, and certainly
would have been an option in a bigger ‘lot of water moving’ big wave venue.
However betwen the two sets of fins, they are missing this small overlap area about
3/16" beyond my regular set to the rear, that the newer custom made set
by Larry doesnt reach up that far.
So I took a hack saw and cut out the rear stay of a probox insert(probox inserts run about $5 or more) and now can get
an additional 3/16" to the rear adjustment without having to grind the rear tab on an FCS Occy fin ($70).
3/16" sounds like a little and it is but when searching for the ‘sweet spot’…its necessary.
So betwen the two sets of fins I have an area to the rear for adjustability that is fully covered without grinding
on fin tabs.
This will cover my sweet spot territory, its just a matter of a couple of more HH or plus surf days to adjust
and correct.

For the record:
From a structural standpoint cant note or imagine any negatives about cutting out the rear stay on an insert.

http://www2.swaylocks.com/node/1025082?page=2#comment-1255145

4

FYI

for tapping into plastic and thin sheet metal I use a small variable speed reversing drill motor with the tap chucked in it

zip in , zip out, done

5

Otis, Interesting Post. Also a treat to see your mechanical mind at work. Great to see people pushing the boundries and tinker. Thanks for sharing Otis, NICE JOB(-:

Mahalo,Larry

www.ProBox-Larry.Blogspot.com

6

I’ve ground down the side opposite the screws to eliminate a hair’s worth of weight.

I think it’s a figure 8 just for the symmetry given the grub holes. I’m sure I will be corrected.

I’ve noodled on the idea of pouring my own inserts that would provide toe in.

The current inserts are thick enough that if you took an insert out, positioned fins in the boxes at the right toe angle, you could pour your own inserts that could then be used to provide toe and cant.

Those are the key things I’ve been tinkering with…still nothing beyond some mangled boxes at this point though.

7

ProBox - Larry Wrote:

That’s right I forgot about afoaf another tinkering Mad Dog. (=:

Mahalo,Larry

8

if I release probox toe’d inserts before you do, am I going to get sued!?

9

Anybody want to start a pool on what Larry’s response will be?

I’ve got $5 on: Larry; “I’m sure we’ll be able to work something out.”

Anybody else"

10

ProBox-Larry Wrote:

afoaf, You can be my R&D Guy for Toe op’s. Mahalo, Larry

11

bump

someone inquired & a favorite thread :wink:

 

G.Tate: Pic?, I’ll work on it , if I remember. Currently my battery in the cam is probably dead.

You can get a full inch, biased to either fore OR aft  all depending upon

additional set screw positions and grinding the tab.

Some boards are problematic and will need either one.

 

12

very cool.  would appreciate a pic.  fore and aft a full inch is huge.