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Bandsaw circle cutting jig vs drift

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Forum topic by SawdustMill posted 2178 days ago 1928 views 0 times favorited 18 replies Add to Favorites Watch
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SawdustMill

58 posts in 2318 days


2178 days ago

Topic tags/keywords: bandsaw jig question drift

I looked around yesterday and found a couple of plans for a bandsaw cutting jig, then made one.

The problem is that the drift on my bandsaw is so bad that I only get about an inch before the blade is so bent that progress stops.

I’m trying to cut about a 7” radius with a 1/4” blade.

Any ideas how to make it work ?

Perhaps my blade is too dull, or the tension not high enough ?


18 replies so far

View SteveKorz's profile

SteveKorz

2130 posts in 2300 days


#1 posted 2178 days ago

I’ll openly admit… I have very little experience with a bandsaw. But, instead of putting the center pin for the jig 90 degrees perpendicular from the blade (as the miter gauge runs), I wonder if you could find the angle of drift on your blade and then put the center pin 90 degrees to that angle. If you accomodate for the drift, then in theory it should work, right?...

(lol… sounds like a longshot to me, but let me know if it works!)

-- As iron sharpens iron, so one man sharpens another. (Proverbs 27:17) †

View Roper's profile

Roper

1346 posts in 2299 days


#2 posted 2178 days ago

for circle cuts i like to us a jig saw to rough it out then i use a router with a straight bit to clean it up. i also use a circle jig with the router.

-- Roper - Master of sawdust- www.roperwoodturning.com

View Bob #2's profile

Bob #2

3808 posts in 2607 days


#3 posted 2178 days ago

First the blade is not tight enough. Try to tighten it with the guide pushed right up so you can plunk the blade. You can usually hear it vibrate an once you get a fairly striaght cut you can remember the tone it made.
Now you may have to adjust the tilt of the upper wheel on your saw. There is a wheel or nut on the back side that you must adjust ever so slightly with the saw stopped to get the blade to track just ahead of the curve on the tire. The teeth should not be touching the tire when it’s set right.
These are just suggestions.
You may be well served to pick up a book on bandsaws.

Bob

-- A mind, like a home, is furnished by its owner

View lew's profile

lew

9920 posts in 2341 days


#4 posted 2178 days ago

I had the same problem with my home made jig. After playing around, I discovered that I was positioning the jig incorrectly. I found that if I place the jig so that the pin (on which the work is rotated) is “even” with the leading edge of the teeth, I don’t get the binding. Previously, I had placed the pin at the approximate center of the blade.

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View SawdustMill's profile

SawdustMill

58 posts in 2318 days


#5 posted 2178 days ago

Lew, that’s a good thing to try, my pin is just behind the teeth, I’ll try moving it more in front of the teeth and see what happens

View GaryK's profile

GaryK

10262 posts in 2574 days


#6 posted 2178 days ago

lew has it. The teeth need to be on the centerline of your pin.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Loren's profile

Loren

7165 posts in 2234 days


#7 posted 2178 days ago

Set the upper guide as close as possible to the work… and set
the guide blocks close as well.

I’ll rough out circles on the bandsaw but for accurate ones I use
the tablesaw – it produces a circle with less fuss.

-- http://lawoodworking.com

View SawdustMill's profile

SawdustMill

58 posts in 2318 days


#8 posted 2178 days ago

Update: Turns out I had the pin in line with the front of the teeth already. I tried moving a little in front, or behind, but the same thing happened. I’ll try tuning up the blade and tightening up the guides and see if that helps.

If anything else I’ll just make a circle cutting jig for the router. I’d love to get the bandsaw jig working though, even if just for academic’s sake :)

View GaryK's profile

GaryK

10262 posts in 2574 days


#9 posted 2178 days ago

Have you tried to do a straight cut? When you do do you have to angle the board to the right or left?

Do you have a good blade of is it the one that came with the saw?

Is the blade cutting toward the center of the circle or away from it.

Try cutting it 1/8” larger first.

Sounds like you might just have one screwed up blade.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View SawdustMill's profile

SawdustMill

58 posts in 2318 days


#10 posted 2178 days ago

I have to twist the board clockwise looking down at the table. It pushes the blade to the left, away from the pin.

The blade isn’t too old, but isn’t too new either. I think it’s also one that I’ve hit a pin nail or two with, so it’s about time for a new one anyway :)

View John Ormsby's profile

John Ormsby

1276 posts in 2323 days


#11 posted 2178 days ago

One other thing to remember is that every size blade will have a minimum radius that it will cut. Yo might check to see if your blade is too wide for the circle you are trying to cut. This could really cause the blade to bind.

-- Oldworld, Fair Oaks, Ca

View SawdustMill's profile

SawdustMill

58 posts in 2318 days


#12 posted 2178 days ago

That’s a good thought John, although a 1/4” blade should be able to cut a 7” radius pretty easily, or at least, it does when I freehand it :)

View lew's profile

lew

9920 posts in 2341 days


#13 posted 2177 days ago

How about a picture of your set up?

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View rustedtin's profile

rustedtin

4 posts in 2177 days


#14 posted 2177 days ago

It sounds like your blade is dull. I cut bowl blanks on a daily basis up to 6” thick with a 3/8” blade w/3 tpi from 4” to 12” dia.

-- ScB, OR http://stores.twoacreoutlet.com

View Joey's profile

Joey

275 posts in 2401 days


#15 posted 2177 days ago

what type of bandsaw are you using? if it’s a lower powered saw, say a bench top model you may need to slow the feed rate way down. If your pin is in line with the teeth of the blade and your guide bearings or blocks whichever you have, should help keep the blade from binding unless your saw is being stressed or is underpowered.
I have a 14” grizzly and cut circles often up to 12 or 15” in diameter and have never had a problem unless I try and get ahead of the blade by feeding too fast.

-- Joey, Magee, Ms http://woodnwaresms.com

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