Anyone use the 3/8" straight bit?

[heftyh]

I've been using machine for 2 years now and just noticed the 3/8" straight bit online. Part number BST375A.
The picture looks like the edge is sharp for plunge cuts. Can someone verify this?
Also, I cut 3/8" thick polycarbonate. Currently use the 1/8" bit. Lot of problems with polycarb melting in the tip of the bit. Larger flutes of this bit should help evacuation better BUT, is this bit too big to do cutouts in one pass? I try to avoid multiple passes because you can see the steps when each pass increments.
Also, is this a carbide tip, solid carbide, or HSS bit?
Thanks, John

[heftyh]

I'll ask a follow up to my own question:
If I used a larger bit than 1/8" for cutouts, the 3/8" bit I mentioned before as an example, is there a way to use the "inset" function to make the edge of the cut where you want it (without redrawing your patterns).
Example: The cut is "flipped" so I am going around the outside of what I cut. The 3/8" bit is 1/4" larger (1/8" from center) than the 1/8" bit. Can you put a -1/8" value into the inset to move the cut path further out to allow for the larger bit?
I have a feeling that the 3/8" bit is too big to do this. But I am looking at a carbide upcuter that is 1/4". I'm hoping the motor will have enough muscle to run this bit.
Thanks, John

[AskBud]

I'll ask a follow up to my own question:
If I used a larger bit than 1/8" for cutouts, the 3/8" bit I mentioned before as an example, is there a way to use the "inset" function to make the edge of the cut where you want it (without redrawing your patterns).
Example: The cut is "flipped" so I am going around the outside of what I cut. The 3/8" bit is 1/4" larger (1/8" from center) than the 1/8" bit. Can you put a -1/8" value into the inset to move the cut path further out to allow for the larger bit?
I have a feeling that the 3/8" bit is too big to do this. But I am looking at a carbide upcuter that is 1/4". I'm hoping the motor will have enough muscle to run this bit.
Thanks, John

The Inset option box will turn RED if the measurement will not work (not accepted). Remember that the speed of travel will be controlled by the 1/8 bit settings, thus it may move too fast and damage your unit.
AskBud

[HighTechOkie]

The melting you are experiencing is most likely due to you using extruded plastic. You should only cut cast plastics with the carvewright. A larger bit would only increase your problems and most likely due damage to the machine (broken flex shaft probably).

LHR specifies a max material thickness of 1/4" for plastics, though thicker pieces can be cut with multiple passes.

To answer your follow-up questions: Yes you can offset the cut path. In the Cut Path dialog, towards the bottom is "inset" max value is 0.125 or 1/8".

Rob

[hogiewan]

I've only used the 3/8 bit for the built-in jointing operation. Makes a nice clean edge for tracking.

[earlyrider]

I've used it for calibration.
Ron

[heftyh]

OK- thanks for the info. I should be on the right track:
- ordered the Rock Chuck, should be here this week. I checked my QC; I could wiggle the bit/ holder back and forth. My spare was the same.
- ordered a 1/8" single flute upcut Onsrud bit from MSC. Just came today. The flute is huge so this should help with evacuation. I will have to grind the back side of the bit so it will plunge.
- brought home some flex hose, nozzle, and clamp to make an air jet on spindle. Is it OK to unscrew one of the truck bearing holders to mount the clamp through ??I checked on the polycarb I buy. Sheet polycarb is only available in extruded. Acrlyic on the other hand, comes extruded or cast.
Thanks, John

[Digitalwoodshop]

NO on the bearing screws in my opinion.... They STRIP easily, the heads are SOFT.... You are better off sticking the plastic square tabs they sell for Zip ties with double stick tape on the back.

Make sure the bits you buy have the PLUNGE Tooth on the bottom and are sold as a PLUNGE Bit... NO NO to non Plunge bits.

NO NO NO to Extruded ANYTHING Plastic... It melts to the Bit....

Only CAST Material.

As for who is using the 3/8 bit... I use it to cut wood signs to mimic the plastic router template and a hand router. I needed to match the sign style for a development. I came up with using the 3/8 inch plunge bit and Modern Font and Outline Mode and a .15 depth. Works great....

See my website for sign pictures. http://www.poconodigitalwoodshop.com/hemlock_farms_hfca_signs

AL