Replies

1. 
   Andrew | Nov 13, 2002 07:10am | #1

   BTW, i have already rounded the back of the blade and just measured the set at .010" per side.

   and now things have just gotten weirder. i can cut a curve if i"m cutting clockwise, but it will bind if i'm cutting counter clockwise.

   
   

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   Edited 11/12/2002 11:17:05 PM ET by Andrew

1. 
   StanleyNiemiec | Nov 13, 2002 09:56am | #2

   If it is cutting one way (sun-wise) and not another (anti-sun-wise) I would immediately suspect different side clearances on the set.  Either that or the teeth on one side have been damaged or are not as sharp.

   Cutting hardboard must produce an incredibly fine dust.  And relatively speaking, it is not going to be a very smooth cut because of the severed ends of the fibers.  I doubt if any of this dust is being retained in the gullet and it is completely spilling and being grabbed by the ends of the severed fibers.  As such it is likely packing between the blade and the uncut hardboard in the kerf and preventing you from following your desired radius of curvature.  A greater set (more side clearance) might be beneficial but it may also be necessary to have a very good exhaust system to remove that fine dust as well.  

2. 
   DennisS | Nov 14, 2002 09:31am | #3

   Andrew-

   I had a similar situation a while ago - what rang the bell was the difference between cutting curves either right hand or left hand. What I found was that the blade had a horrendous drift to one side. Have you checked the blade drift to see how severe it is? Mine, too, was a carbide blade but in my case I was cutting severely green wood that the inside of the blade, the side that rides on the wheels, got really, really gummed up before I noticed what was going on.

   Cutting masonite in your case wouldn't cause a lot of gumming up of the blade I wouldn't think, but there may be a problem of excess drift that makes the difference between cutting curves in one direction vs the other.

   Cleaning the blade I got rid of quite a bit of the drift but not all. For cutting curves I found it was simply easier to go with the flow and cut them in the direction the blade wanted to go.

   ...........

   Dennis in Bellevue WA

   [email protected]

1. 
   Andrew | Nov 15, 2002 12:14am | #4

   yeah, the blade drifts off to the left a little bit. now i've been messing around with this blade on some scrap wood some more and have found that i could cut my 1.5" radius's in a 2 x 4 feeding either way but not in a 3" thick chunk of maple.

   because the masonite shapes are being mass produced time is an issue and i want to cut as thick a stack as possible, and i also have to follow a line very accurately as the saw cut is the finished edge. sometimes this blade was leaving a mark free edge and sometimes i was getting waves because of vibrations.

   I don't know what to think, as this blade seems to have a mind of it's own and i have to get cutting soon. I remember hearing that when troubleshooting a machine it wants to tell you what's wrong, you just have to learn how to speak its language. so i guess it's off to the shop to have another talk with the bandsaw :)

1. 
   StanleyNiemiec | Nov 15, 2002 05:12am | #5

   Bloody hell man  --  the machine is talking to you and you are refusing to believe what the answer it is giving you  --  mainly that you have got a bad blade:

   1.  Saws properly only some thicknesses accurately

   2.  Follows radius of curvature one way but not the other

   3.  Someimes will not allow you to saw a curve that is within normal limits and specifications for blade thickness

   4.  Smooth cut sometimes; vibration induced waviness other times.

   You must somehow be under the assumption that blade manufacturers are superhuman and never make mistakes, their workers never have an attitude problem,  never have someone operating a machine that is not properly trained or has excessive variance within QC standards that allows a bad one/batch to get shipped out.

   You seem to know something about bandsaws and their set-up.  You have certainly tried to tweak this one into working doing everything that you think possible.  Rather than searching for answers further in your navel lint, call up the blade manufacturer and ask them what the hell is going on AND if necessary, have them ship you a new blade.

   If you bought a new car and it would only climb easy hills and the steering worked in one direction and not another, you would start screaming.  Start screaming and start complaining about all the time you have wasted trying to make the thing work.  And if they do not provide superb customer service  --  please indicate that in another posting on this thread so that other forum users will know not to buy those types of blades!

1. 
   Andrew | Nov 15, 2002 08:17am | #7

   yeah you're right, I just keep on hoping that it's something wrong with me or the saw because the blade was specially made and shipped across the country for me, and to top it all off the shipping company lost my first one. all in all it's taken about 3 weeks to get to me and held up my business.

   in the mean time i was getting by with a carbon steel blade but they dull so quickly, and the last thing i want is to have my $200 blade come after i've completed a large number of orders which would have paid for the blade. further more the results that this blade has given me when it has been cutting well are outstanding.

   I've been playing telephone tag with the blade expert at DoAll, as he is the only guy that seems to know anything about this blade. Unfortunately he mainly works on site so he's really hard to get a hold of. I'll have to call these guys tomorrow and see what they can do about getting me a new one.

   while i've got your attention i need to ask your expert opinion. if i'm going to get a new blade from these guys what do you think of powdered metal blades. a sales rep i was talking to @ DoAll was saying these will outlast even carbide, although i've never heard or seen them before.

   thanks

   andrew

1. 
   StanleyNiemiec | Nov 15, 2002 10:21am | #8

   Whenever there is "new" technology, getting the bugs worked out is part of the often exorbitant price  --  you're paying the bill so get what you want and need.

   I was surprised when you set that the carbide blade had set teeth  --  I don't see the advantage of that and quite frankly, I see it as a real potential for problems (as you are apparently experiencing.  As I said earlier, my guess is that you have uneven side clearance (due to uneven set).  This will cause uneven distribution of spillage from the gullet and therein push the blade toward the other side. 

   I do not know whether they are grinding or punching the gullet  --  I suspect they are punching it and this may create a burr that may instead be the problem if the side clearance is equal.

   I don't know anything about powdered coatings  --  sorry!  I assume that their purpose would be to either provide a smoother surface (therein reducing frictional forces) or it provides greater resistance to the high temperature corrosion associated with dulling.  Certainly these thin coatings at the tooth tip (cutting point) would not deter plastic deformation of the edge (the other primary cause of tool wear/dulling).  If you accept and understand these dulling phenomenon, then the rep may be able to provide you a more understandable explanation as to the benefits of powdered coatings.  Does Do-All have a web site that talks about this material?  If you can provide an address, I will try and find time to see what they are about.

   The primary advantage of both carbide and stellite is their greater resistance to high temperature corrosion than HSS.  Stellite (a cobalt based material) is brazed onto the tip and then like an applied carbide insert, ground to shape.  I know that Laguana has/had formed tooth (full width - no set) blade with stellite tipping but I think they were available only in fairly wide widths.  I knew one guy who bought one for resawing and he was extremely pleased with the results.  He attributed it to the hardness of the stellite (which is actually softer than HSS so that was not its benefit) but my feeling is that the teeth were side ground and therefore had less variation in side clearance (ie no erratically set teeth).

   I used to work for Masonite many years back at their R&D Center.  Tool wear can occur also from high mineral content woods (eg teak) that contain silicas and from gritty debris that gets into the chips/furnish in fiber/particle board manufacturing.  This "junk" is as bad on tooling sharpness as actually "rocking" a blade (hitting a nail or stone).  I raise this issue because if the hardboard you are using is gritty, the carbide tipped blade you are purchasing could still be susceptible to rapid dulling.  You might just want to do some comparative analysis of cutting costs for each blade type (based maybe on $ per 100 pieces).  I know it seems like a waste to go through bunchs of carbon steel bandsaw blades but they are relatively inexpensive.  The additional factor to consider is downtime associated with blade changes  I don't know how critical this might be unless you are changing blades every 15 minutes.   

3. 
   blacksmith5 | Nov 15, 2002 06:05am | #6

   Andrew has any one said any thing about blade tension? If not find out about it. With out the proper tension blades can do amazing things

   Richard