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Forum topic by Steve Kreins posted 01-04-2014 09:55 PM 1184 views 0 times favorited 17 replies Add to Favorites Watch
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Steve Kreins

358 posts in 1091 days


01-04-2014 09:55 PM

Topic tags/keywords: jig question tip help

I’m having a serious problem and I can’t figure it out, but I bet one of you can. I’m using a router for shelf slots on a bookcase. I’m using the jig I made as a guide. I need a dado 3/4” + a smidge. (that’s a Texas word that means, well it means a smidge)

Here’s the problem: I make my first pass and it’s perfect from start to finish. Using 1/2” bit. I move the jig back 1/4” + a smidge, clamp jig and make second pass. oops!
The dado starts out at exactly 3/4” but blows out about half way through. It’s still flush to the guide, guide, work piece are all still 90* dead on.

First pass 1/2”, second starts at 3/4” ends at about 15/16th”

HELP!

-- I thank God for everything, especially all of you!


17 replies so far

View Woodendeavor's profile

Woodendeavor

276 posts in 2067 days


#1 posted 01-04-2014 09:59 PM

The first thing that comes to mind is the climb cut is sliding your jig as you are cuttingIf you slide the jig 1/4” to the other side of the first slot do you still have the same problem?

View JustJoe's profile

JustJoe

1554 posts in 1499 days


#2 posted 01-04-2014 10:01 PM

First pass Second pass
__[

I’ve always been terrible at deciphering ascii art. Is that someone playing hangman? If so – is there an E? How about an N?

It sounds like this might be the start of the problem I move the jig back 1/4” + a smidge
Perhaps when you shift the jig and reclamp it is not clamping straight. You think it is, it looks like it is, but in reality the far end is shifted 1/4 + 2 smidges instead of one smidge.

And a pic of the jig in action might provide some hints.

-- This Ad Space For Sale! Your Ad Here! Reach a targeted audience! Affordable Rates, easy financing! Contact an ad represenative today at JustJoe's Advertising Consortium.

View Steve Kreins's profile

Steve Kreins

358 posts in 1091 days


#3 posted 01-04-2014 10:06 PM

JustJoe, YOU WERE TOO FAST I CORRECTED IT. ;)

-- I thank God for everything, especially all of you!

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JustJoe

1554 posts in 1499 days


#4 posted 01-04-2014 10:12 PM

I think your jig is either not being clamped straight when you move it, or like woodendeavor said – it’s being pushed out of whack when you rout.

-- This Ad Space For Sale! Your Ad Here! Reach a targeted audience! Affordable Rates, easy financing! Contact an ad represenative today at JustJoe's Advertising Consortium.

View GOOD LUCK TO ALL's profile

GOOD LUCK TO ALL

418 posts in 1188 days


#5 posted 01-04-2014 10:14 PM

Router base round or square? Square….you may not be keeping it flat against the fence the whole way.
Or you jig is moving, can’t be much else…

View MarcoDivetta's profile

MarcoDivetta

3 posts in 1087 days


#6 posted 01-04-2014 10:16 PM

Is the same part of your router base touching the jig on the second pass or turning it as you move ??

Some router bases aren’t exactly centered so if you register a different part the router base on the fence or roll the router as you move it would give you a different cut .

Hope this helps

View Texcaster's profile

Texcaster

1138 posts in 1134 days


#7 posted 01-04-2014 10:20 PM

Have you considered biscuit joinery for that sort of joint? It’s just as strong and much faster.

-- Mama calls me Texcaster but my real name is Mr. Earl.

View Steve Kreins's profile

Steve Kreins

358 posts in 1091 days


#8 posted 01-04-2014 11:51 PM

YOUR ALL CORRECT not being clamped straight, Square….you may not be keeping it flat against the fence the whole way, roll the router as you move it, Have you considered biscuit joinery for that sort of joint. I’m a real newbie and haven’t learned any joints yet. This my first REAL project.

Here’s what I figured out: My clamps were throwing the alignment off. Hard to see at the time.
The leg of the jig I’m pointing at needs to be much longer so it stays parallel to the edge of my work piece.

I also figured out that my direction was correct on the first pass, but need to be in the opposite direction on the second because I was on the opposite side of the dado.

Thanks for the tips and feedback. You guys are a blessing to me. Someday maybe I can build or buy a router table or get a dado set for my table saw.

-- I thank God for everything, especially all of you!

View gfadvm's profile

gfadvm

14940 posts in 2150 days


#9 posted 01-05-2014 01:55 AM

Steve, I “trap” my router between 2 straight edges when I need to route dados. ShopNotes had a write up on this jig/technique years ago so I can’t find a link for ya. I use the stock that needs to fit in the dado to set the 2 straight edges.

I can send you a pic of mine if you need more help.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Steve Kreins's profile

Steve Kreins

358 posts in 1091 days


#10 posted 01-05-2014 02:02 AM

gfadvm, great idea! Thanks I’ll try it during half time. ;)

-- I thank God for everything, especially all of you!

View gfadvm's profile

gfadvm

14940 posts in 2150 days


#11 posted 01-05-2014 02:10 AM

Send me a pm if you need more info.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View grumpy749's profile

grumpy749

228 posts in 1838 days


#12 posted 01-05-2014 02:18 AM

Steve what you really need to do is cut the dado in one pass. that means buying the correct bit namely a plywood bit for cutting a dado the same size as your plywood. which by the way is not 3/4 inch its 23/32 or .720 Unless you have some sort of oddball size plywood down there in Texas. I’m talking hardwood ply such as oak or maple.

-- Denis in Grande Prairie. Yesterday is history, tomorrow is a mistery, but today is a gift. That is why it is called the present.....Pink !

View GOOD LUCK TO ALL's profile

GOOD LUCK TO ALL

418 posts in 1188 days


#13 posted 01-05-2014 02:57 AM

”Steve what you really need to do is cut the dado in one pass.”

Why? I don’t see the difference.

Steve,
I think gfadvm is talking about something like this. I’m sure his is different but this is the concept.

View Steve Kreins's profile

Steve Kreins

358 posts in 1091 days


#14 posted 01-05-2014 04:49 AM

Now I’m confused, but that’s nothing new. ;)
Actually, in Texas our usual tool of choice for everything is a chainsaw. I’m still trying to figure out how to do a dovetail with one.

-- I thank God for everything, especially all of you!

View rg33's profile

rg33

83 posts in 1462 days


#15 posted 01-05-2014 05:33 AM

Steve, in the future you can try one of these:

www.woodsmithshop.com/download/204/adjustabledadojig.pdf‎

it’s adjustable and should always give you a tight fit. Plywood is never the same thickness even within the same sheet (I learned this from personal experience) so I stay away from those odd sized bits that claim to match the thickness of the ply. Stick to a half inch bit and run it with two passes using the jig I added a link to above.

best of luck

RG

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