Shawn's Table Tuba Build - Dual Loaded 8" Infinity 860W

[shawn_g]

Here goes another build thread. This time I'm building a 20" wide TT that will be fashioned into a table, similar to my previous T18 builds.

I'm using a pair of Infinity Reference 860W drivers. Some of the specs are slightly out of the recommended range, but they're very similar to the JBL GTO804, which has proven to be a worthy contender. I'll post some sweeps from REW when I have it finished.

I'm two days in and only have a few hours each evening to work on it, so I haven't made much progress yet.

The driver:




13mm Xmax!


The layout (reverse layout):


One of the most expensive and useful pieces of plastic I own :




Baffle set into place (not glued yet). I still have to install T-nuts on the baffle:


I'm hoping to get some more work done tonight.

[tuiron]

Good progress, Shawn. Looking forward to seeing the finished product! Are you going with a similar finish to the T18s, or are you thinking something different?

[shawn_g]

Good progress, Shawn. Looking forward to seeing the finished product! Are you going with a similar finish to the T18s, or are you thinking something different?

I'll probably do a similar finish. I'm going to keep using the table enclosure from the last T18 I made in another part of the room (without the T18 in it), so I'm trying to keep a consistent look. Honestly, I'd like to do something different, but I'm kind of locked into the design theme now.

How's your T18 working out for you? I liked the way you did the trim around the table top.

[tuiron]

I know what you mean about being "locked in". I'm still looking forward to seeing the end result.

My T18 table is essentially in the same state as when you last saw it, except that it's in place. The wife has been busy with other projects and work, and hasn't gotten around to doing her bit to it. Role reversal - I'm actually waiting on her to finish a piece!

[Bas Gooiker]

I'm trying to keep a consistent look. Honestly, I'd like to do something different, but I'm kind of locked into the design theme now.

Just go crazy... i say bumpercar purple, gold flakes for the exterior. Persian carpet for the horn mouth. and pictures ofc.

[Radian]

Shawn, are you certain that driver is going fit in there? That magnet looks fairly proud.

[shawn_g]

Shawn, are you certain that driver is going fit in there? That magnet looks fairly proud.

I had my doubts when I first took them out of the box, but I did a trial fit last night and it looked to have around 1/2" or more of clearance at the tightest point. It'll definitely be a snug fit though.

Just go crazy... i say bumpercar purple, gold flakes for the exterior. Persian carpet for the horn mouth. and pictures ofc.

[bassmonster]

Sick build!!!

[shawn_g]

I didn't make much progress last night because my nearly 40 year old Craftsman table saw is going through a mid-life crisis. When I turn the switch on, the motor hums and the blade turns backwards by a few degrees, but that's it. From looking around, it might be something as simple as dirty contacts inside the motor, so I'm going to take it apart tonight to clean everything and see if I see anything obvious. Here's the parts schematic for the motor.

I'm no electrical engineer, so If anyone has any ideas on what might be wrong, I'm all ears. If I can't fix it myself, I'll be table saw shopping this weekend.



Before the saw quit, I finished up the baffle and got a few more panels attached. Here's a picture to show the driver clearance.

[Bill Fitzmaurice]

the motor hums and the blade turns backwards by a few degrees, but that's it.

Probably a blown winding. A motor shop may be able to fix it.

[shawn_g]

Probably a blown winding. A motor shop may be able to fix it.

I just got off the phone with a local shop and got a ballpark estimate of $100 to fix it after I explained the problem. The saw has other issues, so it might be time for an upgrade.

I'm still going to crack the motor open tonight to check for anything obvious, but I'm not hopeful at this point.

[Bill Fitzmaurice]

For a hundred you should be able to get a new motor, which is simple if it's a belt drive, not so much if direct drive.

[matt996]

It looks like an induction motor from your schematic, and based on the age and the hum and movement you describe, I would bet that it's a blown capacitor (item 15 on your drawing). That should be a fairly inexpensive part to try replacing - just make sure to match the capacitance and voltage specs of the original. Voltage spec can be greater, but not less.

[shawn_g]

It looks like an induction motor from your schematic, and based on the age and the hum and movement you describe, I would bet that it's a blown capacitor (item 15 on your drawing). That should be a fairly inexpensive part to try replacing - just make sure to match the capacitance and voltage specs of the original. Voltage spec can be greater, but not less.

Thanks for the info.

[shawn_g]

The table saw lives!

I disassembled the motor to discover that it was caked with 38 years worth of fine sawdust. To my surprise, it fired right up after cleaning/reassembly and worked great for the rest of the evening.

I had a birthday party to attend, but I managed to get a few more panels installed.