proof of spiral blades early death

[Carl E Jacobs]

I have proven at least to my self what causes to early death ,and early dulling of
Spiral blades ,which caused me to not use them too much . I posted earlier about ,sevier problem having ,cutting 4 -1/4 stacks ,total 1" .Finally last nite I
had a releation ,of how to prove my theory .I installed a fd baltic birch in my dewalt 788 placed a scrap edge piece of the afore mentioned stack in front of the blade and cut out a very small U,removed the blade ,installed the same blade faceing backwards ,pulling now instead of pushing now to cut ,extreamly difficult and slow process to cut the same type U ,reversed the same blade back to it's correct position ,cut like butter as before .That V I talked about in the first post is enough to radically change the blade tooth angle to the wood adversly affecting the cutting process,dulling and superheating the spiral to
stretch and break. My conclusion is that even short stack life and sharpness
are effected to a lesser degree when attemping to back straight up with a spiral blade,because with a spiral blade in any direction you are cutting with one 1/2
the radius of the blade in any direction you cut,consequenually ,when you dull
a blade in any direction you are dull the blade partially in the 90 degrees each side at the same time ,further effecting all cuts. It appears side cuts and front cuts have little or no problems ,ONLY when you back up,so now I simply cut
only three ways ,and turn one side or the other to avoid backing up ,and now
4 plys is not a problem. Try the test for yourself !I assume all saws stroke is the same ,but do not really know!
Hope this helps some one some way!
My Very Best !
Carl

[Carl E Jacobs]

proof positve

after posting last,I had another brain BURP ,I went back to the shop and installed the spital blade in the saw upside down ,and held down and pulled cutting from the back side,reverse of normal ,and it cut like butter ,proving again the V, I described is the cause of spiral blade failure when backing straight up .To avoid the problem all together ,turn your work and cut from sides and front and I would say at all times ,even with short stacks ,enen though it will cut single or double stacks It has to be dulling and shortening the life of the blade. all my tests were done on four stack 1"ply.

Now I that I found all this out I will be using Spirals a lot more ,Mikes ,swears
by the new spirals ,and the UR s .he shipped my order tues.I desided I needed
a better holder keeper ,for selections ,before they arrive,so I built the 24 tube
lazy susan ,pix below.

My very best Carl

[Terry Murphy]

That is a great looking blade holder.
Thanks for sharing.

[stephenD]

I haven't read your other posts so this may be non-relevant.
I think the saws have a forward movement of the blade on the down stroke. Would that have an effect on cutting with the back of the blade?
I didn't notice any difference when cutting forward or backward, side to side when I used a spiral recently. But that was cutting pine and only one project. Not conclusive but only anecdotal evidence.

[ChuckD]

I use spirals a lot and when ever I can I cut into the blade just like flat blades. I know that is taking away one of the advantages of spirals but I can cut in any direction without any problems but do what is comfortable to you.

[Carl E Jacobs]

Spirals are great now!

Chuck, I only explored ,my constant ,breaking problem In what was deemed a over loaded condition,by all who responded to my original post.I could not except that as the total answer,I persued it,proved the real reason for the problem ,decided to post the whole thing ,including the cure in hopes of helping some one else ,who might be having issues with spirals .Not for any other reason . I have learned quite a bit from this forum myself and was only trying to repay kindnesses shown,not infer or alter anyones methods they are happy with !
My Very Best!
Carl

[ChuckD]

Carl, you did a good job. That is what we all do, explore until we find what works for us.

[Paul Shank]

I Am a newbie nd was going to order spiral use for tight cut and in turnes Woud this a bad Move?

[lucky788scroller]

I Am a newbie nd was going to order spiral use for tight cut and in turnes Woud this a bad Move?

In my opinion yes, that would be a bad move.You cant get the nice crisp curves, and nice long straight gentle curves very well with a spiral blade.

[Carl E Jacobs]

no ! The problems I incountered were seriously amplified because of the excess hieght of the thickness of the stack and the number plies with glue between ,the biggest factor was the stroke cycle V,I described ,This only applies to spirals in
backing straight up,simple plan your cuts to only cut form the front and both sides never straight backwards,any stack under 3/8" you probably will never know any difference ,other than your blade life will be shorter .With this knowledge you can now stack higher saving a lot of time on items you want to make more copies of ,I was cutting avery detailed eagle for my four sons for Christmas presents.After I discovered the cause of the massive blade failures and cut as described it was a pleasure ,thankfully none of the failures ruined the piece,A side note ,when you multistack ,you are making a lot of fire wood all
at once ,so extra care is needed ,to eliminate major boo boos !
plan your work -work your plan ! Experiment ,enjoy,and learn from your mistakes ,every one of us has had BOOBOO S some MINOR SOME MAJOR
my very best to you!
Carl

[lucky788scroller]

Carl. In your experimenting with spirals, have you did any experiments cutting with different sizes of the same type and brand of spirals in various materials, and if there is any advantage to using a say number 3 spiral compared to a 2/0 spiral? I did no real scientific study of this, but from my experiences a #2/0 spiral performs just as well in any material and any thickness as a # 2 spiral (I havent used any larger than that), and last just as long.It sounds like a bunch of bull-honkey, but in reality it makes sense to me when I really thought about it.It takes less effort to cut with the smaller 2/0 blade because its making a much smaller kerf. Its true there isnt as much material in the blade to absorb the heat caused by friction, but likewise, there isnt as much heat caused by friction compared to a larger spiral blade, of which takes considerably more effort to cut the same thickness of material simply because its just bigger.I used the same size spiral (a 2/0 ), on small stacks of BBply, up to 1 1/4" thick red oak, and have been pleased with its performance anywhere in that range. Thoughts?

EDIT: Carl, I agree with you on your cutting direction in relation to your saws stroke. It is my opinion that all the sideways and pulling pressure put on the saw when people are using spirals has got to be extremely hard on the saw, and I bet that has a lot to do with the premature wearing out on many scroll saws.A bicycle is made to go forward, try riding one sideways, and see how long it will go before theres flat spots on the tires.

[JCJAGS4560]

New to spirals

Good mornin or evenin - that is whenever you may read this reply.. I am brand new to using spirals - and am having some difficulty liking them.

I cannot seem to direct the blade along a line without it straying at some point and I cannot see them being used for cutting puzzles because of the large kerf produced and I am using an Olson No. 0 when I try this.

Is there any book or mag that details beginners trials, errors, solutions ?

Thanking you in advance

Jeff

[hotshot]

As I read your post, I couldn't help but think of the blade travel on the 788, but Stephen beat me to the punch. I you lived close, I'd let you try this same experiment with the Hegner which has almost no travel. In my mind, the spiral should cut the same in every direction, and if using all sides of the blade, the dulling should be even on all sides.

-------Randy

[SawTooth]

Jeff /Bowhunter69,
1-You have discovered why you shouldn't use spirals for puzzles... other thin, flat blades are better because the kerf is always thinner and the cuts are always smoother.
2- The New Scroll Saw Handbook by Spielman is a great resource, even though it isn't as new as it used to be. Other books for general scrolling techniques incude Scroll Saw Workbook by John Nelson and a couple of books by Boelman & Spielman (I can't recall the titles) and, in general, any books published by Fox Chapel because whatever the subject of the book, they have great instructions and pictures to teach the technique. Also, Steve Good's Scrollsaw Workshop Blog has a lot of instructional videos (google it).

[jim_mex]

Hi Jeff - For general scrolling info I'd second buying Spielman's book. I bought it along with my saw and it gave me lots of general and valuable information along with plenty of ideas of which way to approach scrolling.

I've been scrolling about 4 years and still have a love/hate relationship with spirals and I only consider using them for portrait work for 'nibbling' designs out of birch ply which is something they excel at. When it comes to cutting anything with lines or curves I much prefer standard flat blades. Having said this I know of folks who use spirals for more conventional scrolling and swear by them.

One thing I have noticed is that using spirals on a budget scrollsaw where it's quite common to find an oscillating back to front blade movement gives worse results that on a more precise top end saw where this movement is minimal.

@Carl and Dale - thanks for going to the time to experiment and post your findings. All good info.