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Uneven cut when cutting off box tops

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Forum topic by SiRiC posted 08-17-2017 10:19 AM 762 views 0 times favorited 15 replies Add to Favorites Watch
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SiRiC

4 posts in 1838 days


08-17-2017 10:19 AM

Topic tags/keywords: box

Hi,

I make boxes and cut off the tops on the saw. I use the method of cutting just shy of the wall thickness so that there is a sliver to hold the top until the process is complete.

What I find however, is that when I make the second cut, it tends to be off by a tiny fraction giving a slight lip between the two sides.

https://s3.amazonaws.com/vs-lumberjocks.com/outr89p.jpg

I have tried cutting the sides sequentially, tried cutting opposite sides but it really does not make a difference.

Would appreciate any insight into solving this.

Thanks

Steve

-- Measure twice...ummm.. i forget the rest!!


15 replies so far

View Andy McCormick's profile

Andy McCormick

31 posts in 3412 days


#1 posted 08-17-2017 10:57 AM

Your bottom of the box is not flat. If it’s not flat it will transfer the unevenness to the cut.

-- Andy, Liberty,Indiana, www.mccormickwoodworking.com

View dhazelton's profile

dhazelton

2597 posts in 2113 days


#2 posted 08-17-2017 11:02 AM

I’d say your blade is not at 90 or the fence moved on you.

View Gene Howe's profile

Gene Howe

9675 posts in 3245 days


#3 posted 08-17-2017 11:29 AM

To eliminate the problem, finish the cuts with a hand saw or sharp knife.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Aj2's profile (online now)

Aj2

1155 posts in 1614 days


#4 posted 08-17-2017 12:37 PM

Bandsaw does a better job. Thinner Kerf one pass and it done.
With a table saw you have to keep rotating around the mismatch your seeing is how flat your bottom is.
Just as Andy Mc Cormick mentions.

-- Aj

View hotbyte's profile

hotbyte

989 posts in 2792 days


#5 posted 08-17-2017 12:46 PM

Could fence to blade alignment also have an impact on final cut alignment???

View jeffswildwood's profile

jeffswildwood

2496 posts in 1794 days


#6 posted 08-17-2017 01:06 PM

I think fence alignment would make a mis cut on all four corners. I go with bottom not flat. Just a little off will do this. I too have had this happen, It’s a bear to fix!

-- We all make mistakes, the trick is to fix it in a way that says "I meant to do that".

View Carloz's profile

Carloz

876 posts in 408 days


#7 posted 08-17-2017 01:09 PM

I have a question for you too. How do people manage to make 3 post on the forum in 5 years ?

View rwe2156's profile

rwe2156

2690 posts in 1297 days


#8 posted 08-17-2017 01:15 PM

There are a several factors but I doubt it is the saw.

If the reference face of the box against the fence isn’t 1) perfectly parallel, 2) or if the bottom is not perfectly flush, 3) the sides are not perfectly square to each other.

I would still double check the blade-to-fence for parallel.

-- Everything is a prototype thats why its one of a kind!!

View Dan's profile

Dan

635 posts in 1709 days


#9 posted 08-17-2017 01:25 PM

If the insert is not perfectly flush, or like rwe2156 says, “if the sides are not perfectly square” focus more on pushing box against fence while running through.

-- Peace on Earth

View Redoak49's profile

Redoak49

2856 posts in 1805 days


#10 posted 08-17-2017 01:35 PM

For a long time, I used the table saw to cut off box tops. I switched to use the bandsaw and it is much better. I use spray adhesive and attach a sheet of sand paper to 1/4” MDF. I use this for sanding the bandsaw cuts smooth. This method works much better for me.

View BurlyBob's profile

BurlyBob

4959 posts in 2082 days


#11 posted 08-17-2017 01:50 PM

I use a piece of a wide sander belt – 24”, clamped to my table saw. I sand the bottom flat so the box sits with no rocking. Once I cut the lid I do the same thing to the lid and box. Makes for a nice fit.

View Ripper70's profile

Ripper70

554 posts in 725 days


#12 posted 08-17-2017 02:44 PM

Here are two methods that may work for you:

How to Saw Off a Box Top

Cutting a Lid from a Box

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

View tmasondarnell's profile

tmasondarnell

62 posts in 1606 days


#13 posted 08-17-2017 05:17 PM

Steve,

I was having the same issue and found that it was caused by two problems already identified:

1. The bottom of the box was not flat.

2. I was not keeping the box tight to fence—particularly on the short cut.

View SiRiC's profile

SiRiC

4 posts in 1838 days


#14 posted 08-17-2017 05:37 PM

Thanks for all of the responses!!

I make sure to keep the box tight to the fence, so it is most probably the flatness of the box.

Had tried the band saw and it was easier but the teeth marks afterwards kind of deterred me – will try again though as it easier to sand the marks than having to correct the incorrect cut from the tablesaw.

@Carloz, did not realise that I was an offender for not posting regularly!!

Thanks again,

Steve

-- Measure twice...ummm.. i forget the rest!!

View Jim Finn's profile

Jim Finn

2566 posts in 2738 days


#15 posted 08-18-2017 08:49 PM


”.....Had tried the band saw and it was easier but the teeth marks afterwards kind of deterred me ….”

Thanks again,

Steve
In the past 9 years I have made, and sold, well over 2000 boxes and I cut the tops off with a band saw. I then lightly sand the cut, with a random orbital sander, to remove the saw marks and move on to the next box.

-- No PHD, but I have a GED and my DD 214

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