Plasma cutter not firing

I have a HF 95136 plasma cutter. I pulled the cover off the cutter and installed the supplied splices onto the torch wires. I can squeeze the trigger and it will arc. But, when I activate the torch with Mach3, nothing happens. I have good air pressure but it’s not making a spark. Any help would be great. Thanks.

Hi @mater1331

Did you check for continuity between the metal contacts of the jack at the end of the torch fire cable? This should be checked with the plasma cutter off and with the trigger squeezed. Release the trigger and you should lose continuity. My initial guess would be that one of the t-tap connectors isn’t making good contact with the trigger wire.

Do you have the motion controller plugin and the Crossfire v1.1 configuration installed in Mach 3?

Bingo!!! The T-Tab splice was not making a good connection!!! I can trigger the torch on and off. Now to try and cut my first piece.

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Please post some pics of your first cuts!

I think I’m going to have to get another plasma cutter. This cutter I have just doesn’t have enough strength. I was cutting 5/16” plate. It’s a 240v an I slowed the speed down to 35ipm with 60psi. I ran the program twice over the cut and after the second time, the outer edge was cut thru about 90% of the way around. Any help would be great.

PS setting up the tool paths for each part kicking my butt!!!

@mater1331 For 5/16" with the Harbor Freight cutter I would recommend installing brand new consumables in your plasma cutter and running the program at 15 IPM and 40A. Instead of posting a new program each time you can use the Feed Rate Override feature in Mach3 to slow down the cut speed. 15IPM is 43% of 35 IPM (the programmed cut speed) so just click the green Vertical bar in the Mach3 Feed Rate Override control until 43% Override is shown. Hope this helps!


In addition to what Mike says, i would recommend going with at least 1.5 seconds of pierce delay to make sure you pierce all the way through before initiating motion.

Also, dumb question, but is your work clamp secured to the material? If not, then your plasma cutter will only operate on the pilot arc which will gouge the material, but not cut through it.

I couldn’t figure out how to change the cutting speed on Mach3. I was thinking it was just controlled by the “Setup” and “Cutting” tabs in Fusion 360. Also, the torch cut all the way thru the meatball before it started moving but it seems like it needs to slow down more or be turned up (but it was at 40A). Also, the clamp was on the drain plug of the water table per the plasma cutter setup video on YouTube. I didn’t think it was an issue bc the torch was firing and stay on but not cutting thru in some spots. I verified the pics was level along with the slat bed. I honestly think I just need to slow it down more. I’ll try it some more tomorrow if I can get home in time.

My bet is that you are right. 35ipm seems pretty fast for a harbor freight machine. The Hypertherm Powermax 45 cut chart recommends cutting at ~37ipm at 45 amps. But the Hypertherm has significantly more power than the harbor freight unit. I would start at 15ipm and go from there.

I will try this tomorrow evening when I get home!!

Bump up your air pressure up to 72 to 75 pounds

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Good call and yes you are right. 60 psi seems low. Most manufacturers recommend between 70-80.

Sorry guys, been out of town for work and haven’t been able to mess with my table until this evening. I cut out an axle tab to mount a link bar. The piece turned out good after I turned up the air pressure to 73psi and slowed down the cutting speed to 10 ipm. My only complaint is I think I had the speed to slow because of how much build up was on the bottom side of the cut. I’ll try to upload pics or the video from my phone but I’m not having any luck so far.

Glad to hear you were able to get a part cut out. You should be able to upload pictures directly from your phone by clicking the photo icon.

I just screen shot the back side of the final piece.

Here is the front side

Congratulations on cutting out your first part. How easy does the dross chip off? 5/16 is thick enough that dross should be minimal so you could probably run a bit faster.