Jasper circle JIG Model 200

[Ian Mackenzie]

Just a short note on progress with the Jasper Circle Jig.

All is going according to plan.

I have successfully cut one baffle, it took a while but I think steady progress (not rushed ) is the key to success here.

Actually, the spacing and setting the actual baffle cut out diameters was a real challenge.

Many thanks to Bo for his assistance.


There was also quite a bit of preparation including a special framing jig which had to be arranged to hold the 2 18 mm MDF panels in precise alignment while cutting.

Because of the flange diameters were much larger in diameter for the 2307 and the 2405, the inner and outer layers had to be cut seperately while maintaining the same centre Pin hole for the Jasper circle jig.

I will post some work in progress pics in a few days. Its really starting to look like a 4345 now (no cardboard baffles here Bo)

Ian

[boputnam]

Originally posted by Ian Mackenzie
Its really starting to look like a 4345 now

Dang it - I need to get to the hardware store with the 4301B's in tow, and see if they can match that JBL blue...

Hey, Ian...

I got baffled (sorry...) a bit by the part about the flanges and the "inner and outer" layers. What you got goin' on, there... You cuttin' both baffles at once, or...??

[Ian Mackenzie]

Bo (damm Yanky) let me explain the dang thing,

Boy the baffle framing jig does two things:

It positions both layers of mdf in (1) exact alignment and allows the Jasper circle jig to swing (2) freely over the mdf surface with intrusion of clamps, bolts etc.

Using two layers of mdf does complicate the cutting process and requires that they be initially stacked atop each other so when the centre pin drill hole is drilled it is in precisely the same position on both mdf layers. (compendo)

The holes for the 2245 and 2122 are cut straight through and therefore both mdf layers need to be in exact alighnment when the router bit cuts through the top layer.

After the top mdf layer is cut it is lifted out of the baffle framing jig and inner layer is raised with some packing and then cut. (The 1/4 in router bit is only long enough for 1 inch deep cut)

The 2307 and 2308 have a bolt flange which is larger then the actual baffle cutout diameter, as the depth of the flang is less than the thickness of the 2 mdf layers the lower mdf layer must have a hole equal to the flang diameter. So the circle jig is adjusted to cut the larger hole before cutting the lower layer.

So there you have it boy,



Ian

[boputnam]

So, I think I get it now (not that it matters, just curious...) - you are making the baffle double-thick (2x 18mm). You refer to "two layers" - this is gonna be one whopper of a cabinet... I now understand what you mean about the 2307 and 2405 - your baffle is much thicker than original.

I like the idea of the raised Jasper-jig rig (is that redundant...?) avoiding clamps is always a hassle.

Nice,

[Alex Lancaster]

Ian: Are You making Yr baffle board 36mm thick?, or making 2 at the same time.

Bo: You don´t qualify for Yank privileges, You´d have to go a few thousand miles E by NE.

Alex.

[boputnam]

Originally posted by Alex Lancaster
Ian: Are You making Yr baffle board 36mm thick?, or making 2 at the same time.

Bo: You don´t qualify for Yank privileges, You´d have to go a few thousand miles E by NE.

Alex.

Alex... That's the root of my confusion (at least on this thread...). I had thought he was cutting both L/R at once, you know, with one laying upside down. But, the bit about the mounting flange on the 2405, and it's throat being too short, suggest Ian's doubling the thickness of each baffle, to 36mm.

And, yea, I do. Rooted in NewMexico and Nevada by way of being born in Manhattan (NYC). At the very least, both my goldens are from Maine (Little Country Goldens - Link ), so that counts, too..

[4313B]

I've decided I would prefer the blonde to do all my future loudspeaker building for me. She maintains an impeccably clean work area, dresses smart and has a great smile. Plus she keeps her hair up while working for safety concerns and lets it down when she's done.

Excellent!

[Ian Mackenzie]

Bo takes the prize 36mm

DammYankee

macka

[boputnam]

Originally posted by Giskard
I've decided I would prefer the blonde to do all my future loudspeaker building for me...

But how do you choose!??

[Ian Mackenzie]

Yeap,

Phillips had the right idea with their diy drivers in the 70's.

Nearly got baffles for both boxes cut.

All the drivers fit perfectly (" swell "for you Yankee's...muhahahha) thanks again to Bo's precision measurements.

Then will make the dog boxes and attach'm with mitred corner cuts of F17 hardwood scewed/glued to the inner baffle like a brick shit house which should brace and strengthen the whole structure.

Then a bit of delicate inset work on the front layer for the 3mm aluminum level contol plate and drill driver mounting holes. Decided will buy new L pads like the 50watt jobs with 1 inch shaft (Parts Express260-255).

Will probably with have the level control plate enagraved (and etched) with a computorised Artwork router by my sign writer guru neighbour Morpheus. (an Englishman who hates a Guinness)

Should look just like the original with a bit of effort.


Ian

[4313B]

These are the L-Pads I use on high performance midrange drivers such as used in the 4343/4344/4345 - Parts Express 260-265
They are an 8 ohm version of the high power 16 ohm JBL 51594 ceramic L-Pad.

[Ian Mackenzie]

Thanks for the tip.

Ian

[Ian Mackenzie]

Tried the Parts Express 260-265 but they wanted US$35.00 in shipping which made me look else where. (the whole order was around $36.00 worth)

I finally found a local outfit called Altonics who carry what appears to be identical hardware for Aus $16.75 each and probably comes from the same factory. The model I ordered has a 1 inch shaft which will allow securing via the inner baffle layer

I scoured the web for some time looking for these devices and they appear to come in 15, 30, 50 and 100 watt ratings, the higher rating units appear to be of better quality.

http://www.altronics.com.au/cat.asp?...rp=68&id=A2110

Also another interesting link:


http://www.colomar.com/Shavano/lpad.html


Ian