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DIY Betsy question (Read 2391 times)
Coyote
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Posts: 182
DIY Betsy question
12/23/21 at 20:16:33
 

Hello everyone,

With the holidays approaching I am going to treat myself to a few items. Some of these being router bits for my upcoming Betsy project.

I am an absolute novice with routers so I am hoping someone here can help me out.

If any one is in the know.

For the edges of the baffles can I use a "straight bit" or flush bit to make the edge nice and straight?
I do not want to corner edges  rounded off but do not want to be 90' what would that bit be called?

For the drivers (Lii F15s) I need to cut the hole in the baffle, I have  a jig to cut circles what bit would that require?

The driver is mounted from behind so I need to route a small edge so the driver ring fit "inside" the back of the baffle, what is that bit? Then I chamfer the front side.

I am thinking of of giving the baffle a 3 to 5 degree negative angle so I need a 'straight' bit with an angle, does that exist or do I need to make some kind of jig?

Finally any suggestions on a quality brand for bits? I am more for buying a few quality bits than a cheaper 'kit'

Thanks to all,

Happy Holidays,

Alain
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My modest system:
SE84UFO2.(2).
Quad mono 303 (x2) + 33 + FM3.
Marantz 2235.
Schiit Mani.
Technic SL23.
Thorens TD160 MKII + SME III tonearm. Ortophon OM10.
Oppo CD/DVD.
Celestion Ditton 66 studio.
Lii F15 in Betsy type OB.
ATAUDIO 12TC Pure OCC.
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Bilyeaux
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Posts: 147
Re: DIY Betsy question
Reply #1 - 12/23/21 at 22:59:09
 
Might try the DIY thread and/or the Betsy thread farther down list for speakers. Good luck! Sounds like a cool project
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ARC LS25MK2, UFO2.1 & Denafrips Pontus II DAC, PSA P300 Regen, Rega P6 w/ NEO and Rega MM Phono, Marantz CD6006, Bluesound Node 2i, Nakamitchi Cassette, Syzygy Sub, Omega JR XRS Towers & 74' Heresy rebuilt from Crites, ZWIRE speaker, DSRXLR, AQ connects
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Brian
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Posts: 897
Re: DIY Betsy question
Reply #2 - 12/24/21 at 02:09:12
 
Hello, Alain
"I do not want to corner edges  rounded off but do not want to be 90' what would that bit be called?"
Not rounded and not 90 degrees sounds like a bevel or chamfer.
I do not know the names of router bits myself.
Merry Christmas,
Brian
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Coyote
Seasoned Member
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Posts: 182
Re: DIY Betsy question
Reply #3 - 12/24/21 at 04:10:19
 
I love this community.
Thank you
Brian and
Bilyeaux

Cheers,

a.
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My modest system:
SE84UFO2.(2).
Quad mono 303 (x2) + 33 + FM3.
Marantz 2235.
Schiit Mani.
Technic SL23.
Thorens TD160 MKII + SME III tonearm. Ortophon OM10.
Oppo CD/DVD.
Celestion Ditton 66 studio.
Lii F15 in Betsy type OB.
ATAUDIO 12TC Pure OCC.
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CJinArcadia
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Posts: 38
Re: DIY Betsy question
Reply #4 - 12/24/21 at 13:36:06
 
As a novice, my first (strong) recommendation is to plan on practicing your cuts/techniques before moving on to the actual baffles. Are you planning to cut the bigger side arcs with the router as well? Is your circle jig long enough? (If not, you can do a diy jig.)

You could purchase the bits individually, or just go get a set of commonly used bits. Make certain that the bits for dressing edges have actual bearings. (It sounds like you need at least a straight and a “chamfer with bearing”.)

You can cut the holes and sides with a Straight bit. The size will impact how much material is removed, and also impacts the cutting of the back shelf/lip. You’ll need to plan the sequence of the cuts. For example - since you are wanting a recess for the driver’s front edge to fit in on the back, you’ll want to cut that before you cut the actual hole (unless you buy some other specialized bit with a bearing).

I’m confused as to what you want your edges to look like. If not round over and not a straight 90 degree, then are you wanting a cove, chamfer, ogee , etc? I’m guessing you want a small bevel, in which case get a 45 degree chamfer bit. This is also what you’ll use to bevel the front side of the hole.

Regarding the cuts so that the baffles have a small angle (or tilt), I’m not familiar with any way to easily do this with a router. I’d use a table saw or a circular saw for those cuts. (I suppose you could develop a sliding wedge jig for the router, although I’ve never seen this done.)

Plan for making multiple passes for your cuts, and again, practice using your jig(s) and router before working on the real baffles.

Chris
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Raspberry Pi/allo DigiOne streamer/server; MHDT Orchid DAC, Unique Audio tube pre; diy Curtis Spud amp; anticable & diy cables; diy Betsy(alnico) & Buck speakers
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Acozynut
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Posts: 10
Re: DIY Betsy question
Reply #5 - 12/24/21 at 16:05:17
 
Straight bits are best used for jigs and when you have a guide for your router,  the router base needs to be pushed against your guide.

Flush bits are when you have a pattern for the bearing at the top or bottom of the bit to run against,  more for patterning or copying.

Chamfer bits come in different angles and have a bearing at the top of the bit similar to the flush bit.

Frued router bits are very good and stay sharper longer.

Some routers have tilting bases or you could make a jig for the negative angle.  Might find some jig ideas by looking at wooden horn builds.

I would definitely try these on scrap wood
Hope that helps
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Coyote
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Posts: 182
Re: DIY Betsy question
Reply #6 - 12/25/21 at 22:41:28
 

Well Thank you all,

I am learning all sorts of new words here ! Smiley
Chamfer bit, straight bit, etc.
I google these and got plenty of ideas!

I think I want to do a straight cut on the edges that will be the 90 degree with the router then a second 'pass' with a 1/8" "chamfer" bit.

For the barrel shape I am thinking of making a template with 1/4" plywood and clamp that on the "butcher top" piece of wood that will become the baffle. And run the router against that template. I learned that it may be necessary to make multiple shallow passes or do a ruff cut with a skill saw or circular saw and just clean-up the cut with the router. Now I understand what you meant Chris!

Excellent point about making the recess before cutting the actual whole for the driver otherwise there would be no material to slide the router on, ...just a whole!

Then the angle around the front of the whole would be a bevel bit.
I am not sure how I do the bevel while leaving enough material to screw the driver from behind, so more research needed here.

I found this to cut the negative angle:
https://www.toolstoday.com/v-9445-47144.html?ne_ppc_id=15153909030

But I do not understand where that bearing 'sits' as I am cutting that angle unless I clamp a piece of sacrificial wood under the piece used for the baffle.
I do like the idea of using the circular saw, I do not know why I did not think of that, maybe because I am excited with my new router toy.

Yes, I think it is going to be a fun project.
And Yes, I definitely intend to make a first attempt with a piece of cheap ply.

Cheers,

a.


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My modest system:
SE84UFO2.(2).
Quad mono 303 (x2) + 33 + FM3.
Marantz 2235.
Schiit Mani.
Technic SL23.
Thorens TD160 MKII + SME III tonearm. Ortophon OM10.
Oppo CD/DVD.
Celestion Ditton 66 studio.
Lii F15 in Betsy type OB.
ATAUDIO 12TC Pure OCC.
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Archie
Seasoned Member
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Posts: 2731
Re: DIY Betsy question
Reply #7 - 12/25/21 at 23:36:45
 
That Amana angle bit looks good but the angle the baffle sits at is much steeper than 3 degrees.  Cut close with a skill saw and finish with the router.  Clamp a guide to run the saw and the router base against.  I hope you have a beefy router since full depth cuts in hardwood will really stress the router.  The rear support will be more difficult to bevel since I assume it will be quite thick.  You could use "thinner" stock and glue it up after it's been beveled.

I mounted my baffles to the front and used a 1/2" radius round over for the back of the baffle hole.  I think a radius is better than a chamfer here.  You can do the opposite if you want to rear mount the drivers.  Personally, I like the front mounted look.  Unless you go extreme on the chamfer/radius you should have plenty of meat left for the screws.

BTW, you won't have a 1/8" chamfer bit.  Chamfer bits are one size and you adjust the chamfer by raising and lowering the bit relative to the router base.  I used a 1/8" radius round over bit for my outside edges.
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ZLC
Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
Homemade Big Betsy Speakers (F15s)
Silver Cabling
DIY Isolation platforms under amps & TT.
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Coyote
Seasoned Member
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Posts: 182
Re: DIY Betsy question
Reply #8 - 04/06/23 at 23:47:23
 
Archie,
2.4 years ago I forgot to thank you for that comment!
... I just found out how to see replies to my posts!

a.
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My modest system:
SE84UFO2.(2).
Quad mono 303 (x2) + 33 + FM3.
Marantz 2235.
Schiit Mani.
Technic SL23.
Thorens TD160 MKII + SME III tonearm. Ortophon OM10.
Oppo CD/DVD.
Celestion Ditton 66 studio.
Lii F15 in Betsy type OB.
ATAUDIO 12TC Pure OCC.
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