Heat Coil Presto 1-c

[Tony Remple]

I've done some searching around but am not finding the basic info i need.

I recently got a presto 6N with a 1-c head and 90A amp up and running. Done some test cuts, and while I'm thrilled to just get some decent results (oh my god this is a satisfying craft!) I would like to get cleaner, less noisy cuts. Time to heat up the stylus I think, but I really don't know where to start. I'm sure this has been covered on this forum, so if someone could point me to the proper thread(s), cut and paste some info, or just straight up tell a dude what's up it'd be much appreciated.

thanks all, and thanks for this great resource.

[Aussie0zborn]

You've come to the right place! Try the search function on this forum and Im sure you will find a host of information. Some Presto users here might have some good tips too but the search function is a good starting point.

[Doug6N]

Hi Tony:

I'm using a 1-C with heat. I just glued a couple small alligator clamps to cover of the head. With small peices of insulating material under them of course. I also filled in the space between 2 teeth with a peice of wire to make a flat. The lead from the stylus heating coil is clipped under that. Works great. And no drilling or damage to head shell is required.

Power for coil is supplied by a variable supply. Very low output. I'm typically at around 250 ma. Too hot and ya get more noise.

Hope this helps

Doug

[Tony Remple]

thanks. definitely a help. I feel like i've seen pics of retro-fit units that aren't homemade, but I guess building my own wouldn't be too difficult. oyu wouldn't be interested in posting some pictures of your unit so I could see what you're describing would you?

[Doug6N]

Check your system email

Doug

[Tony Remple]

does anyone have any tips on a low cost, low output variable power supply?

[piaptk]

I'd love to see the pictures as well. I've jsut picked up a Presto 1c and some Transco long shank styli (with the wire) and need to figure out how to rig up a heater. I'm not super mechanically inclined, but I can solder and follow directions pretty well. So, if you have any speciifc power sources that you would recommend, I would be eternally grateful!

[piaptk]

Would something like this work? Would I just have to attach the wires from the stylus to the outputs via alligastor clips?

[markrob]

Hi,

Sure it would. Here is a link to a picture of my DIY head.

http://home.comcast.net/~markrob1066/pwpimages/Cutter%20Bottom.JPG

If you look to the right, you can see my early setup using aligator clips. Back when this was taken, I used the wire harvested from a 5 ohm 5 Watt wirewound power resistor for the heater. I used to slip it over the stylus shank. Because it was not thermally coupled to the shank vey well, It needed a bit more energy to get the heat up to the correct temperature, but it worked.



Mark

[piaptk]

I just found this thing at a thrift store and I am thinking it *might* be perfect for a stylus heater. I was thinking about cutting off the end and soldering some alligator clips to the end. It is an adjustable heat electric blanket power supply. It is 45W/120VAC.
Here are my concerns:
1. That I might electrocute myself.
2. That it won't work at all
3. That it will overheat (if that is possible/likely) my needle and hurt the needle or my cutter head (1-c).

Sorry I'm such a newbie, but any help on this is GREATLY appreciated...

[markrob]

Hi,

I'd stay away from that. Its meant to work with AC mains powered heaters. You want a low voltage adjustable DC or AC supply. If you have some electronics skills, this could get you started:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-216

You would have to add an external transformer like this:

http://www.radioshack.com/product/index.jsp?productId=2103732

and a heat sink for the LM317 voltage regulator on the power supply.

http://www.radioshack.com/product/index.jsp?productId=2102856

You might also need an external power resistor in series with the heater coil to allow the supply to be run a higher output voltage. This would give you a more control over the heat. A current meter would be a nice addition as well.

Mark

[Simon]

https://lathetrolls.com/viewtopic.php?t=1037&highlight=&mforum=lathetrolls

here are some pics of mine.

[piaptk]

Hi,

I'd stay away from that. Its meant to work with AC mains powered heaters. You want a low voltage adjustable DC or AC supply. If you have some electronics skills, this could get you started:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-216

You would have to add an external transformer like this:

http://www.radioshack.com/product/index.jsp?productId=2103732

and a heat sink for the LM317 voltage regulator on the power supply.

http://www.radioshack.com/product/index.jsp?productId=2102856

You might also need an external power resistor in series with the heater coil to allow the supply to be run a higher output voltage. This would give you a more control over the heat. A current meter would be a nice addition as well.

Mark

My electronics skills are limited to following directions (not schematics) and soldering. Do you happen to have a picture of one put together? Do you have a link to the external power resistor and current meter?

Does anyone have a heater they want to sell? I'd honestly rather put a little money into one that is already up and running than try to build one and possibly screw something up. But, I'm up for a challenge if no one wants to sell me one!

Also, what about using one of these as a starting point? It has 1.5,3,4.5, and 6V options. Maybe wire in a potentiometer to adjust the heat??

Any idiot-proof instructions would be amazing!

[markrob]

Hi,

That might work. But, if your looking for an idiot proof way to do this, consider finding an adjustable low voltage DC bench supply with adjustable current limiting. The advantage of one of these supplies is that you can run it in constant current mode and adjust that rather than voltage. The heater coil resistance is usually very low (a couple of ohms). So you are running into a nearly short circuit. If you run in constant current mode, the supply will float to the correct voltage to produce the desired current.

I was able to pick up an HP 6203B (0-7.5V at 0-3A) supply at a ham flea market for $25 or so. These are very high end supplies and probably overkill, but it works great. There are currently a few on ebay.

Item 230414048951 looks like a good one. It has both current and voltage metering.

Mark

[piaptk]

Hi,

That might work. But, if your looking for an idiot proof way to do this, consider finding an adjustable low voltage DC bench supply with adjustable current limiting. The advantage of one of these supplies is that you can run it in constant current mode and adjust that rather than voltage. The heater coil resistance is usually very low (a couple of ohms). So you are running into a nearly short circuit. If you run in constant current mode, the supply will float to the correct voltage to produce the desired current.

I was able to pick up an HP 6203B (0-7.5V at 0-3A) supply at a ham flea market for $25 or so. These are very high end supplies and probably overkill, but it works great. There are currently a few on ebay.

Item 230414048951 looks like a good one. It has both current and voltage metering.

Mark

Sweet! Thanks! So, once I have that thing, what else will I need to make it work? Just to plug the output up to the wires on the stylus?

[markrob]

Hi,

That's it. The way to setup for constant current is as follows:

1. Turn on supply with no load.
2. Make sure current adj pot is maybe 1/4 turn away from full CCW position (this is a 10 turn pot so you'll get very fine adjustment)
3. Set the Meter switch to 9 Volt position.
4. Check that you can adjust the output voltage from 0 -7.5 volts on the meter. Leave the supply set for full output voltage.
5. Set the Meter switch for .4A
6. Short the + and - terminals with a jumper wire.
7. You should now be able to set the output current to any value from 0-.4A using the current adjust pot.
8. To start, reset the output current back to zero and remove the shorting jumper.
9. Connect the heater wires to the + and - terminals and you should be go to go.

The supply will compensate for any voltage drop in you connecting wires. Slowly increae the heater current to desired level. If you need more that .4A, just change the meter scale to 4A so you can read it.

Hope that makes sense.

Mark

[piaptk]

Mark, that is awesome! Thanks so much!

[piaptk]

Mark, just got my power supply and got it heated up! Works great!

But, now... how much heat do I add? Someone told me it should be hot enough to touch, but not to hold your finger to for long...

[markrob]

Hi,

Glad the supply worked out for you. Hopefully, you'll get some other answers, but I think the best way is to make some silent test cuts at increasing heater currents and find the point the gives you the lowest noise. If you are using a Transco stylus, it might be worth it to give them a call and find out the max current rating on the heater, so you don't go too far.

Mark

[piaptk]

So, yesterday I managed to break or burn up (I know at least one of them caught on fire and disappeared in a flash) the heater wires on 2 of my needles.

Did this happen because I had it too hot, or because I had the wires crossed and tangled (which I'm pretty sure I did when they caught fire) or both/either.

Just want to make sure I don't make whatever mistake I made twice.

Also, as a vote for Transco's customer service, they offered to rewire them for me at no charge.