Scrollsaw Workshop Community -Please register to enable posting.
General Category => The Coffee Shop => Topic started by: Gabby on February 06, 2011, 06:47:15 pm
-
I decided to go out and make some practice cuts, and get a little time on the saw. It was overcast and chilly but I decided to tough it out. { For those who don't know I've set up in my carport open to the wind. I do have a shop / storage building but it is 300 ft. from power. I won't go into what all brought that situation into being. Suffice it to say lack of foresight. }
About 10 minutes later the overcast was gone!
I had great lighting conditions and proceeded to practice making straight cuts and a few 90 degree turns, and checking to see how well the 2 pieces of wood matched up after the cut was complete. my wavy lines matched pretty good but the more angular cuts not so much. I decided to practice some straight lines on a piece of clear pine 1/2 x 3 x 4 inches. here is where my questions will start. I made a cut across the narrow part first cutting out a glue line just to see what would happen. that wasn't too bad, so I proceeded to do the same to the other end which had been broken of and was splintery. So I laid out a straight line to square up the end. Both of these cuts were rip cuts with the grain. I noticed the blade didn't really want to cut at the start going into end grain. I'd been noticing a little curl of wood in front of the blade and wondered if that is an indication that the blade may be getting dull??
After making the cut which came out fairly straight. :) I cut all but about an inch from one direction, and finished that up from the opposite just to see how close I could get doing it that way. The longer part of the cut was ragged on one side of the material as though it was tearing the grain rather than a smooth cut, and the opposite sidewas relatively smooth, the short part that I back cut was much smoother on one side and the other not as badly torn as on the long part of the cut.
All this long winded dissertation is to set up to ask the question. Are all these signs indications of a dull blade, a too loosely attached blade, or technique of feeding the material into the saw. I'm counting on you experienced people to set me straight. See what happens when a newbie O.F.gets a saw? ::)
Last comment 2 hours vanished like smoke, I only quit because my fingers were getting a little numb! ;D
Thanks in advance,
Gabby
-
Hey Gabby, First thing, Why aren't you watching the Super Bowl? Now for your question. If you where cutting for two hours with the same blade, Yes it is time to change the blade. As a scroll saw instructor I tell my students When the blade is not doing what it should be doing, it's time to change it. I don't set a time limit on the life of a blade, but after 30 minutes of continuous cutting it's probably time to chance it.
Just remember, blades are cheap if you buy them by the gross. So don't risk ruining your project because you didn't want to change your blade.
-
Do not push the wood into the blade - the blade will do the cutting. You just have to "feed" it.
There are also some tricks to get the cut smoother:
First is to tape the wood. Seal it with some packing tape, the glue of the tape will lubricate the blade.
Sanding the wood before cutting seams to be also a good recommendation, at least fragile parts are better sanded first and easier finished after sawing.
Steve has some good patterns for practice in his catalog. The small shelf (http://www.stevedgood.com/smallshelf.pdf) is one you should try - it's not too complicated/fragile and will look nice.
regards
Torsten
-
Gabby, I noticed a big difference when I started using the FD blades...
-
OK Thanks folks, but I think what is being missed here is: The question..
Are the synptoms I have described indicators of a dull blade, or technique?
I was out there for 2 hours but probably not cutting for half that time, due to examining the results and deciding what I would try next. I will replace the blade before I resume practice and will try to replicate the cuts I made and check the results.
Question:
How many times did you poke a hornet's nest before you learned NOT to?
LOL
Gabby
-
Question:
How many times did you poke a hornet's nest before you learned NOT to?
LOL
Gabby
Never!
-
Some blades ar precision ground, a little more expensive and cut better, and some blades are just ground blades. The ground blades the teeth will have a set to one side which causes the blade to cut a little crooked and the teeth will leave on side smooth and one side a little rough.
-
I was in a 'country tavern' once when a guy brought in a hornet nest he found...It was January and very cold...
Fortunately I left and went across the street to the hardware store just BEFORE the nest warmed up and the hornets WOKE UP!
You should have seen all the good ol' boys come flying out the door!
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now back to the question...I am getting the feeling that there are two things to be addressed...
1. Your Tension could be a bit loose. Make sure it is nice and tight and gives a 'pinging' sound when plucked
2. I also think you might be 'forcing' the feed as Torsten suggested. Take your time....slow and steady!
My $.02 worth!
~~~GB~~~
-
I would like to add to GB reply . Steve has a nice program on the left hand side of his blog to help with the sound of the blade when it has the right tension .
Mike
-
Some blades ar precision ground, a little more expensive and cut better, and some blades are just ground blades. The ground blades the teeth will have a set to one side which causes the blade to cut a little crooked and the teeth will leave on side smooth and one side a little rough.
OK now that makes sense to me, If anything I'm probably not feeding fast enough. I'm a little tentative, not wanting to break the blade by forceing it. I did notice that it took more pressure than I anticipated in order to get it to cut. Sort of like trying to turn a piece on the lathe with a dull tool. you end up burning or getting a catch. The sharp gouge cuts like butter.
I want to thank everyone who responded to my questions. I did see Steve's tightening advice and follow it.
Thanks Chief.
Mmike that was probably one of the best trips to the hardware store you ever made! ;D I have to admit i never felt the urge to poke a nest either.
Gabby
-
The quality of your blade will make a difference. You said you had a smoother cut on one side of the board. If you are using a "hardware store" blade, they are stamped and have little burrs on them so one side will be smoother than the other. As far as entering from the opposite side to meet a line, well that just takes some practice. If you feel you are going too slow - speed up. You will find what feels right to you. I was used to cutting pretty fast and after reading some entries on this forum, I tried to slow down and it did take some practice. It is all about what works for you.
-
OK Today I changed out the blade and tried to replicate some of the cuts done yesterday. On 1/4" ply it worked great for a while. I don't remember the exact progression of test cuts, but when I tried to rip the 1/2" pine one side of the cut was definitely smoother than the other, the tear out wasn't as bad as with the old blade.
I was trying some gentle curving cuts on the ply when it suddenly stuck fast bouncing up and down stuck to the blade. After shutting it down I had to spring open the cut with a screwdriver, actually breaking the wood away from the blade. I couldn't find a visible cause for the blade to stick. Putting that aside, Chief's response was verified as far as I'm concerned. I'm going to have to change blades more often than I thought at least if I use Olson blades in the future. My mentor included 6 with the saw we'll see if I have better luck with the FD blades when they get here. Thanks for all the responses.
As for the Super Bowl I watched parts of it and most of the final quarter. I've never been a big sports fan, I lean more to Rodeo and Bull Riding, that's what gets my juices flowing. Takes a special kind of man to be successful at that kind of sport. When they get it right it looks easy but it only takes a split second of inattention to be thrown. Or worse.
Gabby
-
I don't think this is exactly what happened when your blade got stuck, but it is interesting and the shop teacher part of me wants to share :)
when ripping wood the internal stresses can be released causing the two remaining pieces to do different things. Sometimes they can pull apart like a banana peel, other times they will tighen back on themselves. If they go back together they can tighten on the blade and cause all sorts of problems (kickback). It is why a splitter is so important on the table saw. I think pine is good prone to this. I once ripped a piece off a 2x4 and it ended up looking like a corkscrew.
lecture over, test tuesday ;)
Mrs.N
-
I did not know that there was going to be TEST ! I would have studied a lot harder !
Mike
-
lecture over, test tuesday ;)
Mrs.N
OK teacher, I'm ready for my test! ::)
-
OK Teach
Go back and read my last post again. I guess I shouldn't have abbreviated Plywood. LOL
I do know what you are referring to in the internal stresses in a piece of wood doing strange things, cutting sheet metal with a torch will do essentially the same thing. Not that we're into metal work here.
All this being said, I didn't expect this result in plywood due to the alternating directions of the layers.
We live to learn.
When is the test, second Tuesday next week?
I'll bring a shiney red apple. ;D
Gabby
-
That is wood stress mrsn and most pine do this white and red when dry and cut long grain and is a pain if you need to laminate the wood
Jimbo
-
You are probably using a reverse tooth blade. There are a few teeth pointing up at the bottom of the blade to make a clean cut on the bottom of your project. When your wood starts bouncing up and down it is know as "chatter". What happens is the teeth grab and the movement of your blade "bounces" the wood up and down. You can usually put downward pressure on you wood, turn the saw back on, and the blade will break free and continue cutting.
-
I did notice that it took more pressure than I anticipated in order to get it to cut. Sort of like trying to turn a piece on the lathe with a dull tool. you end up burning or getting a catch. The sharp gouge cuts like butter.
I have learned that when you do that it is time to change the blade out so I would say you have answered your own Question when your blade is acting as such change it when it first starts.
As for power to the "Shop"shed run your self a outdoor electric cord cut off one end at the start and then cut off all the ends of a 100 footer until you have enough wire now run down into some PVC pipe (after you have wire nutted and taped all the wires up) dig a trench deep enough to cover over the PVC pipe drill a hole in the wall of your shop to run the end of the cord into. Foam ins. in the hole to block out all of the drafts. Now buy a Power Bar and then plug it in and there you go power to the shop/shed or skip all that and go with Romex if you know what your doing........lol Good luck ;D
-
I'm ready too.....is it 'open-saw'?
Jim
-
Yes! A remedial class, even though it is a test, with MrsN! Takes hands back out of pockets, lifts head up, smiles, eyes brighten and puts a skip in his walk!! :) :) :)
Okay okay, you're married, can't a guy have a crush on his teacher? :) :) :) 8)
Shyly hands MrsN an apple because, your the apple of my eye, but can't say anything because of the apple sized lump in my throat! ;D
Stumbles to his desk, grins, ready teacher! :)
-
OK is there an electrician here that can tell me what Gage cord I would need to go 300+ feet and not have too much line resistance to run power tools like a Jet lathe a craftsman floor model drill press and 6 fluorescent four foot double tube lights, and throw in the scroll saw. I know they won't all be on at one time. I have a 6000W generator that puts out 220 volts split into 2-110 volt circuits one for the lights and one for the outlets, and if I have the lights on and turn the lathe or drill on the lights dim briefly. I don't use it anymore as gas here is nearly $3.50 gallon and five gallons doesn't last long.
If I would be overloading the circuit breaker at the house due to resistance, it's a long walk to go and re-set it, and that would get old in a hurry.
I'm not trying to be snide, but just pointing out an observation. Most responders don't take the time to actually read the questions and as a result their answers are some times off base. I have done so myself so I'm not trying to make myself out as smarter than anyone else, just an observation.
Our responses will be better if we just take our time.
My thanks to those who are trying to be helpful, you are appreciated.
Gabby
-
You are probably using a reverse tooth blade. There are a few teeth pointing up at the bottom of the blade to make a clean cut on the bottom of your project. When your wood starts bouncing up and down it is know as "chatter". What happens is the teeth grab and the movement of your blade "bounces" the wood up and down. You can usually put downward pressure on you wood, turn the saw back on, and the blade will break free and continue cutting.
Nope they all point down.
Gabby
-
@Gabby,
At 300' it would be a whole lot better to put a sub panel in your shop with breakers than to try to bring one line with outlets.
Wire size ( 0 ) Maximum amps for power transmission( 150 )You could have 7-20 amp circuits.
Wire size ( 1 ) Maximum amps for power transmission( 119 )You could have 6-20 amp circuits.
Wire size ( 2 ) Maximum amps for power transmission( 94 )You could have 5-20 amp circuits.
Each circuit would be 120 volts.
One circut could be used for lighting.
Most extension cords for regular duty use are 14 awg or 12 awg at best.
12 awg at 300 ' pulling 20 amps will have a voltage drop of 19.59 v leaving you with only 100.41 volts to work with, really being unaxceptable.
This is just a suggestion/estimations but I feel this would work better for you. 8)
-
hey gabby, sorry you didn't find my lecture notes interesting. I did state that it wasn't the problem you were experiencing, but interesting none the less.
Mrs. N
-
hey gabby, sorry you didn't find my lecture notes interesting. I did state that it wasn't the problem you were experiencing, but interesting none the less.
Mrs. N
I found it interesting and even offered to bring a shiny red apple!
Gabby
-
@Gabby,
At 300' it would be a whole lot better to put a sub panel in your shop with breakers than to try to bring one line with outlets.
Wire size ( 0 ) Maximum amps for power transmission( 150 )You could have 7-20 amp circuits.
Wire size ( 1 ) Maximum amps for power transmission( 119 )You could have 6-20 amp circuits.
Wire size ( 2 ) Maximum amps for power transmission( 94 )You could have 5-20 amp circuits.
Each circuit would be 120 volts.
One circut could be used for lighting.
Most extension cords for regular duty use are 14 awg or 12 awg at best.
12 awg at 300 ' pulling 20 amps will have a voltage drop of 19.59 v leaving you with only 100.41 volts to work with, really being unaxceptable.
This is just a suggestion/estimations but I feel this would work better for you. 8)
Thanks Russ that jibes with my calculations I figured it would cost over $1000 to do because of prices for wire of that gage, and trenching. Just too much money for our budget, should have done it when we first bought the place and still had some money to spend for improvements. Water over the dam. So now I get a scroll saw that doesn't make too much mess compared to lathe shavings and put it in my carport next to the house.
If it's too cold I'll just be in here giving everyone a bad time. Summer time shouldn't be too bad, we only get a few weeks of really hot weather 90 and over 100. I used to work in hotter weather as a youngster growing up near Phoenix, AZ. But I couldn't take it any more.
Gabby