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Thread: New Bandsaw Setup Issues
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9th August 2020, 06:24 AM #1New Member
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New Bandsaw Setup Issues
All,
I am trying to set up my first bandsaw and can do with some help.
It is a Hammer N4400 which has flat tire. I have a 16 mm blade that i believe is positioned correctly and the teeth are positioned just in front of the top wheel tire.
The back of the bandsaw blade passes through the middle insert.
I changed out the guides for ceramic guides and this issue is the bottom guides do not extend out far enough to support the blade. It reaches about 3 mm from the back of the blade fully extended.
Any advice would be greatly appreciated.
Cheers
Ann
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9th August 2020 06:24 AM # ADSGoogle Adsense Advertisement
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9th August 2020, 07:50 AM #2New Member
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Actually the entire blade insert is 70 mm in length of which the blade slot is 57 mm.
the front of the blade itself is 15 mm from the front of the blade slot
the back of the blade is 25 mm from the back of the blade slot
My gut feeling is the blade is too far forward.
Cinsert.jpgheers
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9th August 2020, 08:23 AM #3
Yep, too far forward. The gullet of the band should ride on the crown/middle of the wheel. I have the same bandsaw and can take pics of my set up in a few hours, if you want?
Pat
Work is a necessary evil to be avoided. Mark Twain
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9th August 2020, 08:24 AM #4New Member
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Many thanks, much appreciated.
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9th August 2020, 08:32 AM #5
I agree with Pat, your blade needs to move back. A lot!
Check out Alex Snodgrass’ demonstration on how to set up a bandsaw; I’ve been using this method for a few years now on several different machines and I can tell you it just works. Band Saw Clinic with Alex Snodgrass - YouTubeNothing succeeds like a budgie without a beak.
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9th August 2020, 12:57 PM #6GOLD MEMBER
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This may help
The second post in this thread might also be useful Need advice from someone with Hammer N4400 who likes it
A manual can be downloaded here Manual - Hammer N4400 BandsawCHRIS
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9th August 2020, 03:32 PM #7
Ann, have a look at the vids above. I took pictures but they are not useable.
Pat
Work is a necessary evil to be avoided. Mark Twain
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10th August 2020, 07:02 AM #8New Member
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Picture of settings
All
I have watched all the videos - thanks
I have set the blade as far back as possible - the back of the blade lines up with the back of the rubber. (not desired)
Blade as far back as possible.jpg
The blade still runs through the middle of the insert
Blade as far back as possible1.jpg
I still cannot set the bottom blade guides as the blade is too far forward
I feel i have a wheel alignment issue.
CheersLast edited by aschleiss; 10th August 2020 at 07:09 AM. Reason: pressed submit twice - result a mess
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10th August 2020, 10:20 AM #9GOLD MEMBER
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Ann, don't touch the wheel alignment or you will have problems. I think we are missing part of the story here which is no fault of yours so perhaps the better approach might be seeking help from the distributor in NZ. Pat, didn't you do this conversion on your saw?
CHRIS
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10th August 2020, 11:14 AM #10Member
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When I bought my Hammer N4400 7 years ago the blade was running on the front of the wheels with teeth overhanging. I adjusted the blade to run in the middle of the wheels as per Snodgrass. I had to adjust the tilt of the bottom wheel via the 4 bolts on the hub at the back of the machine. I was advised by the Hammer technician that you can tilt the wheel anyway you want by loosening one bolt and tightening the opposing one correspondingly ((very little is needed). The central bolt also has to bee loosened before any adjustment and tightened afterwards. Unfortunately the manual doesn't tell you this. I also changed over to ceramic guides and after 7 years of operation had no damage to the tyres. I am not sure what the rational is to run the blades on the front of the wheels.
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10th August 2020, 11:26 AM #11Member
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When I bought my Hammer N4400 7 years ago the blade was running on the front of the wheels with teeth overhanging. I adjusted the blade to run in the middle of the wheels as per Snodgrass. I had to adjust the tilt of the bottom wheel via the 4 bolts on the hub at the back of the machine. I was advised by the Hammer technician that you can tilt the wheel anyway you want by loosening one bolt and tightening the opposing one correspondingly ((very little is needed). The central bolt also has to bee loosened before any adjustment and tightened afterwards. Unfortunately the manual doesn't tell you this. I also changed over to ceramic guides and after 7 years of operation had no damage to the tyres. I am not sure what the rational is to run the blades on the front of the wheels.
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10th August 2020, 11:38 AM #12GOLD MEMBER
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Of course the wheels can be changed but if the saw was operating OK and after changing the guides it isn't what happened. There must be a lot of saws changed without the problem having occurred otherwise it would be a well known problem. Speaking to the distributor sounds like a good idea to me before major changes are made.
CHRIS
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10th August 2020, 11:52 AM #13Senior Member
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I just have to ask...
You are moving the guide block carrier plate forward, aren't you? It looks to have around 50mm travel, which should be plenty to extend well past the edge of the wheel.
I notice this is your first bandsaw.
start by popping out the table insert so you can see what you are doing.
There should be 2 bolts holding the lower guide carrier plate to the frame, and one bolt securing the rear of the thrust guide into its mount in the carrier plate.
loosen the lower thrust post securing bolt & Move the thrust post to its rear most position.
Loosen the lower guide block carrier plate securing bolts and slide the carrier back as far as you can on the saws frame, so it is out of the way.
Track the blade to where you think it should be. I would guess that position would be about 2mm from the rear of the rubber on the upper wheel to the back of the blade... but basically it should not matter too much at this stage.
Now tension the blade. Use the the scale if you want. The blade (on the spine side) should be able to be deflected 6mm toward the saw's spine without your finger turning terribly white. Check that the tracking is still correct after tensioning the blade correctly. It probably will not be, as on most saws the blade will migrate forward if you add more tension. Track it back to where you think it should be, if necessary.
Now is the time to set the depth of the lower guide block carrier plate. Slide it forward on the 2 mounting bolts till the ceramic blocks are just behind the gullet. 1 or 2mm will be fine at this stage. Now tighten the bolts up, and take a photo.
Next you should slide the thrust guide post through the center of the guide block mounting plate. It should be able to contact the back of the blade. If it does not, dont worry, take a photo of the lower guide setup from under the table. Take a photo thru the insert hole while you are at it. Photos are cheap and help loads.
Post the photos back here as a reply so we can see a bit more of what we are dealing with.
I am deliberately not dealing with the upper guides here, as it is important to get the lower guides right first, and the photos may well be revealing.
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10th August 2020, 12:28 PM #14GOLD MEMBER
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Taking the detailed post above I would add one thing, remove the table to see what is happening and making it easier to work on. You don't need the table until the mitre slot and blade are aligned and angles set to the blade and fence.
CHRIS
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10th August 2020, 01:28 PM #15Senior Member
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" I am not sure what the rational is to run the blades on the front of the wheels. "
There are 2 types of tyre flat and crowned. Not many people know flat tires can be crowned after you install them. We run all 3 in our workshop (which is not a recommendation).
In General... Flat tires run with the set of the teeth off the front of the rubber. The reason is so the set is not damaged by the tension on the blade changing, as the wheel rotates. Obviously, if the teeth are on the rubber, they are under side compression on top & bottom of the wheels, which is released as they travel free of the wheel in the up and down planes. Repeated rotation can "hammer" out the set, or part of it, in theory at least. The flat of the blade is supported on the flat of the tire, which should point forward, if the axle points forward.
Crowned tires add a curve to the outside of the tire, which means the blade must run on a fulcrum point. To stabilize the blade you need 2 points of contact on the tire. The method of running the back of the gullet on the crown is to support the teeth on the area of the dip in front of the crown. The object of moving the blade slightly forward or backward on the fulcrum is to angle the blade slightly inwards or outward to correct minor amounts of "drift", if drift is defined as not cutting parallel to axles. The flat "back" of the blade rides on the crown/fulcrum,giving the 2nd point of contact. On a crowned wheel it is the flat back which handles the stress of going round the wheel, as the teeth ride in contact with the area with a reduced radius.
In all bandsaws the blade must have a fractionally longer back than front to cut properly, it is the act of pushing wood into the teeth that will deflect it rear-wards, which stretches the rear edge and causes compression on the toothed edge. The blade under load has a very slight scythe shape (The purpose of the thrust guide(s) is to limit this backward travel). The scythe shape where the back edge of the blade is longer means the internal stress on the blade will try to move it back to the same length as the front of the blade (by going round the outside of the scythe curve). This has a tendency to produce a waggle or side-flutter (not harmonic flutter) in the rear edge of the blade. The side guides are there to counteract this side flutter and reduce it to a minimum, thereby keeping the blade pointing (mostly) forward.
The easiest way to understand the above is... if the blade did not have a shorter front than back, then the front of the blade would try to steer right or left by using the blade's rear edge as a fulcrum point.
Hope this explanation helps...
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