How to make my own 8" and 10.75" Futures Routing Template

Has anyone made their own center-fin routing template, for Futures 8" or 10.75" center fin?  I have the “One Pass Installation Kit” which worked great for two twin-fins I’m making, but I also have a longboard and a long-ish egg that I’d like to do a single fin (10.5") and 2 + 1 (8") setup respectively, and I’d like to avoid paying $265 for the “One-Shot Installation Kit”.  (I have the Makita 3709 1/4" Fixed Base Laminate Trimmer, with the routing attachment and bits from the fute One Pass kit).  Hoping to make something out of plywood, got plenty of that.  Anyone done this before and have some guidance?

I have made some homemade install systems but broke down and bought the Futures side fin install kit.

i do not have a Futures LB bit, box, or kit so I could not say with certainty whether a side box kit could rout a center box.

Could you measure a Futures LB box and share that with us? Maybe we can ‘do the math’ as a group.

 

 

 

 

At the minimum you will need the bit with the !/2" collet and a high horse powered router. . The jig you can make to save some money. where the is no lateral or side to side play, just north and south adjustment for the 8 and 10.75" lengths…  Free hand is possible also especialy if you are using a stringer for cenet line. Cut depth of center box to length, place Fin box in and mark foam around flange, remove box and carfully cut flange out with appropriate router and bit.

**The 10.75": **A: 12", B: 1 5/16", C: 3/4", D: 3/4", E: 1/16", F: 10 3/4", G: 3/8", H: 3/4"

**The 8": **A: 9 1/4", B: 1 5/16", C: 3/4", 3/4", E: 1/16", F: 9 1/4", G: 3/8", H: 3/4"

I have a 3/4" bit, so if the only difference is the depth and the length, theoretically I can use the same (side) template with the deeper bit, and just re-adjust to make it longer after doing it once. Still i dont like the idea of passing over already-routed territory

Forgot to mention that this BB30 guy has a procedure for doing this without special fixturing. Mahalo Charlie!

SanFran, Thanks for the dimensions!

The 1/4" shaft x 3/4" deep side box bit will not rout a 3/4" wide slot, it’s ‘deep’ diameter is 1/2". So using the 1-pass side fixture twice to make length will not make this width happen as thought. Plus there is the whole routing through the stringer thing…

If you only have a couple to do, it might be worth ‘networking’ and barter for a couple box routs when needed if you live somewhere near other shapers/glassers.

One could try to figure something out with plywood plates and a 1/4" straight cutter too but Charlie’s way or asking for a favor might put you ahead as far as time and effort go.

 

 

 

 

 

 

I think Surf Source used to sell an install guide for about $20,

$30 bones

https://greenlightsurfsupply.com/products/longboard-centerfin-router-jig-install-kit?variant=40500836237509&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2020-08-27&utm_source=google&utm_medium=smart_campaign&gclid=EAIaIQobChMIxvPftOTz9AIVBwCGCh29QgflEAQYASABEgIwo_D_BwE

btw…I got pretty good at free handing it. Mark and place fin box in dispersed location, tape outside of box real snug, router out CLOSE to tape line and hand sand with 80 grit flush to tape line. Fill box hole with cabosil and or white pigment (or both ) resin blend  (helps with heat build up) to fill the gap during intsall

 

I believe this is for the standard box type finbox: https://bit.ly/3peIYkF

Looking to route for this type: https://futuresfins.com/products/10-75-white-1-shot-fin-box

 

Shoots. Gotcha 

The Greenlight fixture needs the alminum baseplate w/ the built-in bushing according to the red print on the web page. It still seems to be a good option all up for Bahne boxes, especially if you already have that baseplate.

There are a few ways to guide a router::

  1. freehand

  2. Using the router base or sleeve aginst a template (Futures)

  3. Using a bushing on the router base against a template (Greenlight, also available as a woodworking accessory to other routers)

  4. Using a bearing on the bit against a template (FCS, Probox, Gearbox, most of my homemade stuff)

  5. Using the bit itself aginst a template (special cases like chasing a long 1/2" bit in a 1/2" router around an outline template)

  6. CNC

Depending on bit, bearing, bushing, and/or router base size, the template will need to be adjusted in size to get the intended result with the selected combination.

The last template I made on my little CNC allowed a buddy to rout out holes in fake beams to install boxes for LED puck lights using the bushing method. I did not envy him working overhead on 3/4" thick boards. The aftermarket bushing kits take a little tinkering to get the bushing concerntric to the bit. My day job was CAD/CAM for many years so typically I will draw out the ‘situation’ in CAD to work through it and check fits then go to CAM and onto the CNC to make the actual template.

I am now sort of curious about this whole ‘situation’. I have started a piece of EPS blank with a ply stringer and a 3D print of a mock 8" box to see if I can ‘suss it out’.

 

 

 

 

 

So I made up a set of templates based on useing the base of the router as the guide element against the templates at 3.47" diameter

The large wood one is .180" thick  for the flange, the narrow band shrinks it down to do the base. Wood was left over from aomething and not 100% flat.

The acrylic was .116" thick meant to be a ‘target’ about the size of the flange and keep the router off the foam.

The oval with the narrow slot was a backup template for using a top bearing bit. It also would function as a layout ‘target’ for the base portion.

Since I was not dealing with a board, I alowed myself the indugence of clamps and screws to attach the template.

I also pre-drilled the stringer with a 5/8" spade (would have rather used a Forstner) so I did not have to drop a running router bit against a wooden stringer. This piece of ply I used for the stringer was susceptible to ‘blowing out’, I found one toothpick size piece impaled in the foam. I routed the ‘bad side’ of the test piece first in case I wanted to try again or do something else with the test piece. I was wearing PPE, safety glasses and earplugs.

Issues:

  1. I did not draw the target correctly and had to rework it to clear the router bit and flange.

2.  The target is too thick or the main template is too thin to keep router in position while using the stock base plate, the combination allows the radius on the baseplate to ‘escape’ the main template and cause the damage to blank and target seen at label ‘A’. Removing the target allows fixture to work better.

  1. The router base is not 100% round. If one is not careful, the corners catch and the router can dig in funny, causing blowouts at label "B,C,and D’

Remedies/Future Development:

  1. Use thicker, flatter material for main template 1/4-3/8" thick

  2. Remake target, remove during routing

  3. Make a 100% full circle router base from smooth material without the bottom radius.

  4. Continue flange rout to same depth as stringer, add in HD foam, and rerout cavity to create a HD ‘cartridge’ (this would be my normal procedure with EPS anyways)

  5. Re-measure ‘real’ boxes with a dial caliper to get dims in the +/- .005" [.1mm] range and adjust template CAD to suit.

Conclusion:

This is possible but bugs would need to be worked out of current ‘system’ to make nice routs. Making a single template for the flange and freehanding the base might be something too.

PS A small router cannot go after the ply stringer at full 7/8" depth required for a box, it needs to take smaller depth ‘bites’ and even then it complains.

 







The nice thing about the Futures Kit is that it can be adjusted to rout a Bahne FU box as well.  Futures recommends the full size Ryobi Plunge router.  One of the best plunge routers I ever owned was a cheap Skil  purchased at Lowes.  Back around 2000 or so you could buy an Aluminum jig similar to the Futures that was lntended to be used on Bahne boxes.  Haven’t seen those for sale for quite awhile and don’t know who made them.  Bought mine at Fibberglass Hawaii when they were still in SB.  So been awhile.   PS  Where did you get a tan box??

Hi Lowel, the tan box was something I 3D printed at home to have something to play with for the fixture, two PLA filament pieces glued together with PCV pipe cement and (4) 1/8" dowel pins. it is missing the slot for the plate and pin to hold a fin in place. It was made to the dimensions provided by SanFran the original poster.  I have yet to install a 3D printed box in a board.

After messing around on this I can see why a big plunge router is preferred when digging deep in a stringer. I have one plunge router at home, the big brother to the one earlier in this thread. Is that older Bahne fixture a one swipe sort of deal with a large bit or a smaller bit and the routter moved around inside the fixture both ways? Something like this would be easier than what I do now.

The old aluminum jig that I am referring to was similar to the Futures aluminum “One Shot” jig.  The aluminum angle was adjustable to the router base.  The slot was oversized so that there was no chance of contact with the bit.  You had to adjust the angle aluminum to fit your router base.  The router base was run around the border.  Typically a 1/2" straight bit was used and multple cuts were plunged.  I usually made one cut full depth down each side of the stringer.  Then plunge each end of the stringer until it was at full depth.   With a pair of “needle nose” pliers I would break out the stringer in one piece.  Then using the the router clean up the bottom of the slot.  That jig is in storage right now and I can’t access it.   If I could I would take and post a pic for you.  I miss it, because it was set so good and accurate for my Skil Router that I absolutely never botched a fin slot.  Most older glass shops still use those jigs.  They are worth their weight in gold.  I have an old O’Fishl side box jig that is very similar.  I’ll try to get you a pic of that.