slow/high speed question

[Dutchscroller]

Hi all, so iam probably buying a new Hegner next year, but my next question is this.

My current Hegner is single speed, now iam gonna buy a Hegner with variable speed, but when do you use a slower speed and when a higher speed?

Seems to me that when you use slow speed it will be more agressive toward the wood, but i am probably wrong on that. So in what case do you use slow speed??

I never owned a variable speed scrollsaw, so iam tottaly blank on that.

Thanks again

[trackman]

I have a EX21 but I would think be the same with your saw.  When I cut 1/4” wood I will turn the speed down to about half way. Lets me control the cut better.  Everything else I run wide open. 

[JimErn]

Like Trackman I turn the speed down to about half way with 1/4 or 1/8th thick wood, everything else I run about 7/8ths full speed.

My theory, and it seems to work for me on my excaliber, is the faster the blade travels up and down the more strokes clear out the wood especially the fuzzies on the back.

Keep in mind, the speed of blade has nothing to do with how fast you feed the wood into it, fast blade, slow feed rate, it clears out the fuzzies pretty well, and I hate sanding

EDIT - I do use the pegas MG blades, #3 is my goto blade, and they have the reverse teeth at the bottom to clear fuzzies

Edited December 18, 2019 by JimErn

[Scrappile]

If yours is like my Hegner, it will have "sweet spots" where it runs the smoothest.  I have three or four " of them at different speeds.  You will learn yours as you get use to the saw.  I never run my saws at full speed for long.  I don't drive my car at full speed all the time either.  I run mine around mid speed most the time.  You will get the feel for what is best for you.  I also slow down on thin wood.  Faster on thicker pieces.

[Sycamore67]

This is just like what blade to use.  You will need to just try different things.  For me, it depends on the type of woid, the blade, wood thickness, and number of curves and how tight.

I rarely run my saw at full speed.  Some who are in production mode cut as fast as possible.  But, I do it as a hobby.

[Dutchscroller]

thank you all for clearing that up for me.

[dgman]

One question to you. Have you ever been cutting and wished you could turn the speed down because you couldn’t stay on the line? That’s when you would turn the speed down, to have better control of the cut. As a scroll saw instructor, I teach beginners to start at 50%. If you feel you are cutting to slow, turn it up a little till it’s comfortable. If you are cutting and you feel you can’t control the cut, slow it down till it’s comfortable. Seeing as you are used cutting at full speed, you may never need to slow it down. My feeling is you will use the speed control more than you think!

Edited December 18, 2019 by dgman

[MrsN]

14 minutes ago, dgman said:

One question to you. Have you ever been cutting and wished you could turn the speed down because you couldn’t stay on the line? That’s when you would turn the speed down, to have better control of the cut. As a scroll saw instructor, I teach beginners to start at 50%. If you feel you are cutting to slow, turn it up a little till it’s comfortable. If you are cutting and you feel you can’t control the cut, slow it down till it’s comfortable. Seeing as you are used cutting at full speed, you ma never need to slow it down. My feeling is you will use the speed control more than you think!

Dan has really good advise, and it is what I tell my students.  I also tell my students "slower is not easier", some of my kids think that going slower will make it easier and it takes a bit to convince them to speed up.

I personally set my saw to just a bit faster than half way and rarely change it.

[Dutchscroller]

Thanks again, yes iam used to high speed and whas pretty comfortable with it, rarely was i struggling with cutting small delicate pieces, i can only get beter if i can control the speed.

[davidg]

On my variable speed Hegner, there is an attached plate giving recommended cutting speeds for various materials and thicknesses;

1300 - 1400 for wood
1000 - 1200 for aluminium, soft brass and soft copper
600 - 700 for steel, hard brass and hard copper
1200 - 1300 for plastics

I suggest that the recommendations are only general guidelines, as there are many variables. For plastic, I would have thought a lower speed than recommended would be more suitable in order to reduce blade overheating and subsequent re-welding behind the blade, but trial and error will find the optimum speed and feed rate for the material you are cutting with your specific blade. The main point is that with a variable speed machine you can obtain an optimum setting.

You may also discover that certain speed settings give rise to a higher level of vibration of the saw, and increasing/decreasing the speed just a little will improve the situation. An issue for me on the Hegner was the location of the speed control box/dial, placed out of direct line of site under the cutting table. I think the manual recommends setting the required speed first, before switching on the saw, but in any event it is not ideal crouching down or feeling for the control knob under the table. Fortunately, I came across a low cost digital tachometer on Amazon, which allowed me to mount a small magnet under the lower arm of the scroll saw, which in turn actuates a sensor mounted underneath. This sends on/off pulses (based on the proximity distance from magnet to sensor head as the arm raises and lowers) to a wall mounted digital meter, equating to a strokes per minute readout. It still means feeling for the knob to change speed, but at least I now have an independent visual indication of strokes per minute, which is close enough to the actual dial settings when compared. I'm hoping the sensor will also be of help if I experience issues with the speed controller in the future. 

[lawson56]

I don't have a Hegner,But I cut 95% at 1/2 speed,Slower if I need to.I cut with 1/4 wood.

[ike]

I have odwned several saws On my craftman25 years ago I ran it on high speed ( that was it's sweet point) On the dewaltI ran @5 (5 ot  and on my delta I ran @6 dof 8  dit all depends what is moree conforting to you and the machine.

IKE

[NC Scroller]

I probably do 90% of my cutting at top speed.  I never go below 1/2 speed.  If I cut anything that is less then 1/4" thick I will stack at least 3 or 4.

[Rolf]

Lots of variables, Blade, Material you are cutting, detail of cuts. You will need to find your own comfort spots where you have good control no burning of the wood(cherry).

On the EX I run full speed, on my Hawk I have to back off a bit with the small blades or I get a higher rate of breakage. 

[Karl S]

I set the speed where the saw cuts the best depends on the wood and how I feel at the time.

Edited December 19, 2019 by Karl S
spelling

[teachnlearn]

On 12/18/2019 at 8:04 AM, Scrappile said:

If yours is like my Hegner, it will have "sweet spots" where it runs the smoothest.  I have three or four " of them at different speeds.  You will learn yours as you get use to the saw.  I never run my saws at full speed for long.  I don't drive my car at full speed all the time either.  I run mine around mid speed most the time.  You will get the feel for what is best for you.  I also slow down on thin wood.  Faster on thicker pieces.

I don't know about all the state laws, but I don't think you get a ticket if you run the scroll saw full speed. RJF

[Ron Johnson]

I set my speed accordingly to the sound and cutting of the wood, like playing an instrument. You know when it’s out of tune. And never at full speed. Hi 

[teachnlearn]

There are speed charts out there. Might give some a general idea. RJF

[teachnlearn]

[JimErn]

@teachnlearn

those appear to be table saw blade speed charts, "diameter of blade"

[teachnlearn]

I've been kicking that around in my head. Didn't start trying any calculations or anything. There are charts for speeds for materials, I typed scroll saw speed charts on the search. Should have looked closer. Though speed charts for drill, circular saws lathes, bandsaws seem to have a common factor. They seem to give speeds for materials, ie metal, wood, steel, AL, bronze. The circular saw is rotational speed, drill rotational speed, lathe rotational speed. The bandsaw starts rotational, but the blades are a linear speed going one direction. Scroll saw is linear going two directions, traveling so far one way and so far the other, so a conversion of distance would be similar. All these machines tend to have charts that give a speed for a material.

The scroll saw on this board is basically wood blade, some  metal, so if a chart shows a slower speed for metal on other machines, the scroll saw would probably be similar. The scroll saw motor is normally smaller, so speed might compensate for thicker material, though that's going to be a preference. I've been packing and taking a break for my back and didn't do a very good search for a scroll saw speed chart. Wonder, would other machine charts give a sense of speed for the same materials? Just check the board after killing my back for the day. RJF

[Bill WIlson]

I think the point here, Dutchscroller, is to not over think this.  Everyone has their own individual comfort level when it comes to cutting speed (both blade speed and feed rate).  It may vary, depending on the material, blade, saw and pattern, but you will quickly find yours.  I tend to change my blade speed as conditions change, but some run at one speed all the time.  I rarely run the saw wide open, but that may be the norm for others.  It's all about control and comfort level and we all have different requirements in those areas.

[Rolf]

One of the main things is that you want to have is at least 3 teeth touching the wood at all times. 

[teachnlearn]

Grab Travis's practice pattern, buy cheap sheets of plywood, and maybe a few thicknesses, not great finish or fine quality. Get a blade assortment. Maybe if you think you will work with any metal, get a small piece or check roofing and see if there is a small cheap piece. This is cutting and experimenting without any pressure that your going to mess up a nice pattern.

Print out or copy travis's pattern, 10 sheets, more or less. Then just glue them on to the boards and metal pieces. Start at a slow speed and get the feel of the blade. Increase the speed a bit, change out blades and try. Since this is scrape, there is no pressure to mess up a pattern. Take a day and vary the speed, check out blades. You may keep a piece of paper near by for speeds, blade, material thickness to write out for reference. Wear safety glasses. If blades snap, fly, they won't be hitting your eyes.

https://www.scrollsawgoodies.com/wp-content/uploads/2014/03/TCF0003_Practice.pdf

Occured to me writing this. If you can find a sheet of cheap, junk thin plywood go with that. Then tape pieces together to make it thicker, doesn't have to match, your just creating thickness. Either does buy plywood, or wood with knots or cut around them. The machine may grab it and pull the piece of wood your holding. Maybe someone has played with wood with knots, normally that pattern are cut into the wood knots. RJF

Edited December 20, 2019 by teachnlearn

[Bill WIlson]

6 hours ago, Rolf said:

One of the main things is that you want to have is at least 3 teeth touching the wood at all times. 

Last time I tried that, I cut my lip.