Blade tensioning

[Bob63]

I have recently returned to scrolling after a 15 year absence. I have purchased a new type scroll saw with lever tensioning which I am very pleased with.  I may be using it incorrectly and would appreciate some guidance. When using some blades - spirals for example - more than normal tension is required. This may be accomplished initially by using the rear knob. However once the lever tension is removed and the blade released, for moving to another fret hole, this tension is lost as the blade will now be clamped a bit higher and the lever always applies the same fixed amount of tension. To keep adding additional tension by means of the rear knob each time will eventually move the top arm out of alignment and alter the blade front to back movement. So do people release the tension on the rear knob then release the lever tension and blade and then re-tension everything in reverse each time one moves to a new hole or am I missing something ? On the Pegas clamps - normal tension is set with the lever position not fully back - on these clamps can the extra tension be acquired by placing the lever fully back ?  Thanks in advance for your replies.

[Rockytime]

What saw do you have?

[Bob63]

Hi Rocky - I have a Seyco 21

[meflick]

Hi Bob and welcome back. First, I do have a Seyco saw and it is the primary one I use. I have had it and used it since they were first released. However, I have never used a spiral blade in it so cannot respond to using it with that blade.  I do not use the knob to change the tension on the Saw, it was set once and I use just the flip lever to release tension to move the blade to the next hole to cut as needed. I do it the same way with the excalibur Saw I own as well.  Paul, @Scrappile also has the Seyco Saw I know and is a much more accomplished scroller then I with lots more experience, so perhaps he can give you better info, if someone else doesn’t before he has a chance.

[Bob63]

Hi Meflick   Thank you for your reply.  I have only had the Seyco since January but I really like it. I had never used spiral blades in the past but have been taken by portraits so decided I would try to only use spiral blades and spent three weeks playing and practicing with them. One great thing with the Seyco is the ability to virtually eliminate back to front movement on the blade - a blade which is not moving back and forth 1/8" or more is a lot easier to move sideways. I have only done two small patterns from books to date but can see persevering with spiral blades is the way to go for me. Only thing s that spiral blades, for me at least, require more tension and this saw, with the lever, only applies one fixed amount of tension - would be nice if the lever had two positions ( or a changeable lever with a different profile ) 

[Scrappile]

I have a Seyco and I do not adjust the tension know in the back except when I am making sure the upper arm is level with the table.  I do not adjust it when I go from one hole to another.  I don't understand what you mean when you write "this tension is lost as the blade will now be clamped a bit higher and the lever always applies the same fixed amount of tension".  The tension should always be the same as when you first put the blade in the saw.  Could you explain this a little more.  Also maybe @scrollingforsanity well jump in here.  He is a Seyco owner and he uses his a lot more than I do.  My Seyco is more of a backup saw for me. 

And, Bob welcome to the village, be patient, we will get you help.  The are a lot of experts here that have Excalibur saw and they work the same as the Seyco.

[Scrappile]

Bob, Just read the post you made while I was writing the post I made above.  You can apply a little more tension with the back knob when you first put in your spiral blade, but you should not have to adjust it again until you put in a different type of blade.  I know spiral use a little more tension.  It should never require the upper arm to be far from level with the table. 

[Bob63]

Hi Scrappile  I will try to clarify what I am attempting to say.  Given you put a new blade in clamp it and tension it - it now has original tension  - then without cutting you run the machine for 30 seconds - if you stop the machine the tension now will be less as the blade has stretched - you now release the tension and re-clamp the blade higher up on the blade to re-tension back and from now on you should be able to maintain this tension just by clamping and unclamping. However if you want more tension you can increase it by using the back knob which raises the upper arm. This will hold that increased tension until you release the lever and the clamp - now when you re-clamp it the arm remains higher and the blade has retracted because it has lost tension. The result is that the blade goes into the upper clamp at a lower position meaning that the distance between the upper and lower clamp has increased. As you are putting the same stretch via the lever but the blade is relatively longer the tension applied is less. Hope this is at least a bit clearer.  

[hotshot]

Bob, if you need to get more tension than what the lever gives you, I can help you on this, as I've had to do this many times.  The trick is to press down on the arm a bit while tightening the blade in the clamp.  This gives it a bit of tension, before using the lever, so that when you add the lever tension to it, you end up with more tension that what the lever alone provides.

You might ask, "How do I press down on the arm, if I have one hand on the blade, and one on the clamp knob, well, I'm embarrassed to admit . . . . . I lean over and press it down with my chin . . . . yep  . . . . . . did I admit that outloud?

I learned this approach after I screwed up my "Blade Travel" setting by using the back knob.  Now, I never touch that back knob.

-----Randy

Edited February 11, 2019 by hotshot

[Bob63]

Hi Hotshot - Many thanks for that - I will try it.  After re-reading my last reply to Scrappile I was thinking of doing the opposite of tensioning with the back knob - ie. with the blade unclamped turning the knob slightly to the right - lowering the arm a little - just don't know if that would affect the back to front blade movement. Will try you method - sounds safer.

[Scrappile]

@hotshot, you got any pictures of that move!!

[don watson]

Sorry to be a pain but I have been following this very interesting thread from the start.

I have a Lidl scroll saw that cost around £50 and it is all I have used in my short scroll sawing career.

My tensioning on this saw is a combined lever/screw arrangement and I have always used the method described by hotshot (Randy) when using/changing blades with the difference that I tighten the bottom clamp first (I am a bottom feeder) and the hold down the top arm while inserting and tightening the blade into the top clamp.

My big problem is that any mention of the arm being out of sync will let the blade move back and forward while cutting ?? and how can I stop this happening ??

Can I presume that the top and bottom arms should be set parallel while setting up the saw initially ?? I really am at a loss here and will need to reread  this a few times I think.

Don W

[NC Scroller]

Bob are you seeing this with all blade types or just the spiral blades?  "Blade stretch" is minimal at best and should not require any adjustment.  What brand/style spirals are you using?  Spiral blades are tricky to clamp up.  I suspect you have blade slippage.  One way to combat that is to flatten the ends before trying to clamp them.    

[Bob63]

Hi Don ; Sorry to hear your problem as well. My last saw in the UK, many years ago, was an old Diamond Fret Saw and I had no real control over blade back to front movement. It had long threaded blade clamps and by altering the lengths and also tensioning at the back there was some adjustment for blade back and forth movement but I could never say I could make accurate adjustments. These new saws , Excalibur, King, Seyco, Axminster seem to be all the same and are the only ones I have ever seen where one can adjust the blade back to front movement. I assume that they accomplish this with a motor which has its' shaft slightly offset and by rotating the motor mount it gives an eccentric movement to the arm mechanism.  But I could be wrong. There may be other machines with these adjustments but I do not know of them.

[Bob63]

Hi NC,  Yes I am only using spiral blades - FD New Spiral 2/0 and 1.  Many thanks for the suggestion I will try flattening the blade ends - currently I sand them a little but they are not flat so blade slippage is a possibility. 

[OCtoolguy]

14 hours ago, hotshot said:

Bob, if you need to get more tension than what the lever gives you, I can help you on this, as I've had to do this many times.  The trick is to press down on the arm a bit while tightening the blade in the clamp.  This gives it a bit of tension, before using the lever, so that when you add the lever tension to it, you end up with more tension that what the lever alone provides.

You might ask, "How do I press down on the arm, if I have one hand on the blade, and one on the clamp knob, well, I'm embarrassed to admit . . . . . I lean over and press it down with my chin . . . . yep  . . . . . . did I admit that outloud?

I learned this approach after I screwed up my "Blade Travel" setting by using the back knob.  Now, I never touch that back knob.

-----Randy

Randy, I do the same as you but not with my chin. I manage to hold the arm down and hold the blade with one hand and turn the clamp screw with the other. It can be done. And I do it every time. It takes all the play out of the mechanism and "pre-loads" it. I have not had any problems with tensioning and I never touch the rear knob. I do pretty much the same on my Dewalt. But in all honesty, I haven't used any spiral blades yet. I think I did try them when I first started and realized they weren't for me.

 

Edited February 11, 2019 by octoolguy

[Bill WIlson]

I had to press down the top arm on my DeWalt, but it doesn't appear to anything on my EX.

Spirals have always been a challenge for me to get secure in the clamp.  But they won't just loose tension, they pop all the way out. 

There is a set screw in the top of the Upper Blade Tension assembly, specifically in the Clamp Bracket.  It seems to have something to do with how much travel there is in the clamp when the Tension Lever is engaged.  I don't know if this has any affect on blade tension or not.  I've never really messed with it much, but it may be worth looking into, if the Seyco has the same clamp assembly. 

I don't use the rear knob on mine to adjust tension, but it says that you can, in the EX manual.  Just need to make incremental adjustments and I suspect that rather than let the adjustments accumulate, at some point you would need to return the upper arm to parallelism with the table.

[OCtoolguy]

2 hours ago, Bill WIlson said:

I had to press down the top arm on my DeWalt, but it doesn't appear to anything on my EX.

Spirals have always been a challenge for me to get secure in the clamp.  But they won't just loose tension, they pop all the way out. 

There is a set screw in the top of the Upper Blade Tension assembly, specifically in the Clamp Bracket.  It seems to have something to do with how much travel there is in the clamp when the Tension Lever is engaged.  I don't know if this has any affect on blade tension or not.  I've never really messed with it much, but it may be worth looking into, if the Seyco has the same clamp assembly. 

I don't use the rear knob on mine to adjust tension, but it says that you can, in the EX manual.  Just need to make incremental adjustments and I suspect that rather than let the adjustments accumulate, at some point you would need to return the upper arm to parallelism with the table.

That's true. But, if you make the investment in the Pegas clamp set, that is all gone and works so much better. I sort of flinched at having to pay almost a $100 to buy something that was pretty much already on both of my saws but after buying the first set for my EX and experiencing how much better they are, it made buying the second set for my Dewalt a whole lot easier. I did buy the second set of EX clamps to put on my Dewalt because I like the lever system better. I make an initial adjustment with the rotary knob on the Dewalt and then just leave it alone and do all the tensioning with the lever. I love both of my saws now.

 

[scrollingforsanity]

Welcome to the Village. Between everyone helping you will get it figured out. I have never used spiral blades but as the other readers suggested I have had to slightly put downward pressure on the arm to achieve a tight blade.  ( to fat to use my chin though Lol ). I do not adjust the rear knob as that is what I use to get my saw in tune. Once set I have never moved it although I check it once in a while to make sure it has not moved. When I first got my ST 21 and my EX21 they both had a little vibration and the rear knob would turn on it's own and get the saw out of adjustment. I just wrapped a few wraps of electrical tape around the threads under the knob. problem fixed. If you keep moving the rear knob your saw will always be out of adjustment in my opinion anyway. Are you cleaning the blade ends well. The FD blades always have a oily residue after manufacturing.  If you take some alcohol or other cleaner and a clean rag and clean the ends you will see what I mean. You might try cleaning the thumb screw ends as well to make sure they have not gotten some oil on them.  I have the Pegas clamps on my ST21 and the regular clamps on my EX both tension quite well using regular blades. FD Silver Penguin reverse #1 and Pegas MG # 1 and #3.

grizz

[kmmcrafts]

I sort of have an issue with both the DeWalt and the Excalibur with this.. It seems the upper arm doesn't always come down to the same position every time I switch to another hole to cut ( fretwork ).. on the DeWalt I got to where I'd use my one finger to push down on the upper part of the clamp bracket while tightening the thumb screw.. this made it pretty much always consistent enough anyway.. 

Then when i got the Excalibur the tension lever is kinda in the way to do it the same way as I do on the deWalt.. One thing I found helped was to clamp the blade and put tension on it then release the tension and then loosen the screw and the blade would rise up.. putting the tension on ( not all the way ) will pull the arm down sort of as if you was pushing the arm down.. then the arm is where it should be and you loosen the blade then re tighten it.. I don't know how to describe it.. and it does take a extra couple of seconds but becomes second nature to me..

These kind of issues with these DeWalt, Excalibur types saws really makes me like the design of the Hawk even better.. that system is pretty much fool proof and you get the same tension every time all the time..  To describe how it's done on the DeWalt. you can watch how I do it in this video on my blog.. To give the best view of me cutting I taped my phone on the magnifier light.. but then it was quite weird cutting because I couldn't see through the magnifier so I was cutting by viewing the screen of my phone.. so it was sort of difficult.. Many ask me how I place my camera because you get the same view as i do.. and no body else gives this view while cutting.. 

https://www.kevskrafts.com/post/397335857776/how-my-items-are-made 

[trackman]

On my EX21 (top feeder) I put the blade through the hole an with left hand I use thumb and forefinger to pull down on blade an at the same time using small finger push up on the blade clamp. With right hand tighten knob. This takes all movement out of the clamps an arms. Done it so many times I don’t even think about what I am doing. 

[Bob63]

Thank you all for your kind assistance. I have been trying different things today including flattening the blades then getting the two flat ends in the same plane, cleaning ends with thinners as well as slightly sanding them. Sorry didn't get on to well with the chin thing.  It doesn't seem that the blade is slipping but that after doing a pre-tension / pre- stretch whatever it is called although the blade will tension on and off and stay at the same tension, for me at least, the spiral blades need a bit more tension to go where I want them to and not want to wander. For someone with more experience the normal tension would probably be OK.

The only way I found to get more tension with consistency may sound back to front and after reading the message from Grizz may be more wrong than I know. After normal tensioning the spiral blades do not need a lot of extra tensioning to make a big difference for me. What I tried today was to tension as normal then release tension and the top clamp and move the back knob one and a bit, of the finger notches, to the right - yes to the right opposite to the direction normally used to increase tension - then re-clamp the top clamp and re-tension. This lowered the top arm maybe 1/16" further down the blade and, with the  lever giving the same tension movement on the top clamp, effectively increased the tension enough for me. 

 

[Bob63]

Grizz many thanks for your kind and informative message. May I please ask you - when you say don't move the back knob as it will put the machine out of adjustment can you please tell me what adjustments will go out of alignment ?

 

[kmmcrafts]

2 minutes ago, Bob63 said:

Grizz many thanks for your kind and informative message. May I please ask you - when you say don't move the back knob as it will put the machine out of adjustment can you please tell me what adjustments will go out of alignment ?

 

That knob changes the height of the upper arm..  You want the upper arm to be parallel to the table.. ( ie front of the upper arm should be the same distance from the table as the back part of the upper arm.. ) By turning the knob at the back of the saw.. you're changing that distance.. This also in turn will change the aggressiveness of the cutting.. ( forward backward motion of the blade.. While usually minimal but it will certainly change it enough to notice it if you're not careful..    

[Bob63]

Kev many thanks for your comment on tensioning and then re-tensioning I haven't tried this but will.  Also I enjoyed your video always good to watch someone who knows what they are doing at work. Can I ask - as you have both the DeWalt and Excalibur - the DeWalt has an incremental tensioner 1 to 5  - do you always use the same tension on the machine regardless of which blades or work you are doing ?  If you alter the tension as required on the De Walt what do you do on the Excalibur where the tensioner is only one position on or off ?