Bit recommendations for 1/2 and 5/8" Meranti marine plywood

[Greybarn]

Newbie question. I am wondering what the best bit is for cutting 1/2" thick and 5/8" thick Meranti marine plywood? Seems like a 1/4" end mill style bit would work best as we want to drill some reference holes in the holes and then cut parts from the sheets. Is a single flute better than a double flute? Compression? Any other recommendations?
Regards
Peter

[benchmench]

Several other factors to consider such as hold-down method, move/cut speed and depth of cut may help you determine which bit to use.

And, of course your use for the parts you want to cut. Perhaps you don't care if the back edge is ragged.

A 1/4" downcut spiral bit will provide more hold-down, a clean edge on top of the material but a somewhat ragged edge on the underside. It May also have some deflection at higher move speeds or deeper passes. You may want to stay under 6 IPS and 1/4" per pass.

A 1/4" compression will give 2 good edges when cut all the way through. A pocket cut at less than 1/4" will leave a ragged edge on top of the material since only the upcut portion of the bit is in the material.

If deflection is a problem or you want to go with faster speeds and depth of cut, then a 3/8 down-cut sprial or compression may be the answer.

Provide more info and the forum will respond.

[Greybarn]

Mostly, we will be cutting out plywood bulkheads. Other than the aesthetics of the cut, we are not concerned with the edge being ragged. All of the edges will be covered with trim or corner posts. We are using a vacuum hold down system for the sheet of plywood. A 1/4" bit is best as we want to "drill" some shallow horizontal and vertical reference holes.
Are a compression bit and a mortise compression bit the same thing?
Regards
Peter

[mims]

mortise compression bit has a shorter upcut edge at the end of the bit. This can be utilized in a few ways.. if you are putting a shallow mortise or pocket, the upcut will be fully plunged and won't blow out the top edge. Also, if you are cutting thin stock plywood or material (for instance, 1/4" ply), the upcut edge is short enough to not come through the top surface.

[knight_toolworks]

the 1/4" downcut will do most of it. it is not great at drilling but the depth is not bad. it is best to use peck drilling when using a downcut.