Help on choosing a good milling tool

Help on choosing a good milling tool

Postby theoldbakers » Sat Jan 25, 2014 1:54 pm

Dear all,

I am hoping that someone can help me and guide me towards a good milling tool. The ones I currently use leave me wood quite fuzzy and I have been buying ones with either a downward spiral or an upward spiral however this leaves one side of my project needing alot of sanding.

I am cutting Birch Ply Wood to a maximum depth of 18mm. I am only cutting letters and shapes with my router. can any one recommend a good end mill and where I can buy it from?

many thanks in advance.
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Re: Help on choosing a good milling tool

Postby 4DThinker » Sat Jan 25, 2014 2:47 pm

An upcut spiral will leave the bottom edge clean. Downcuts will leave the top edge clean. On a CNC I'll make the first pass with a downcut, then all the following passes with the upcut. They make compression spiral bits that will leave both sides clean if you make a single pass with them.

When I don't have a downcut spiral bit I'll score my cut line .03 deep with a 60 degree v-bit. Then finish with a spiral up.
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Re: Help on choosing a good milling tool

Postby theoldbakers » Sat Jan 25, 2014 3:19 pm

Thats excellent thank you I hadn't thought of that
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Re: Help on choosing a good milling tool

Postby martin54 » Sat Jan 25, 2014 5:08 pm

Not really something I have thought about to much to be honest, most of what I do only requires one side to be 100% so if there are a couple of edge marks on the back it's not really a problem & I haven't cut a lot of ply or other material that leaves one side a bit raggy anyway.

Worth thinking about though for future work, 4DThinker when you say you run the first pass this a downward spiral or 60 deg v bit are you treating that as a separate toolpath & if using the "V" bit running the toolpath on the line rather that outside it??
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Re: Help on choosing a good milling tool

Postby ssflyer » Sat Jan 25, 2014 5:29 pm

Compression (or mortise compression) bits work well, and you don't have to use them in one pass, only make sure that the pass depth is more than the up-spiral part, and that the final pass goes through the material.

However, since I tend to be a bit anal about tearing up my spoilboard, I tend to use down-spiral bits and leave ~0.002" - 0.005" skin on the bottom. This can actually be cutout with my knife, then sanded easily. The downcut bits also pack the shavings into the cut, pretty effectively holding the part in place, w/o vacuum and in many cases, w/o tabs. The downcut also keeps the piece down on the table whereas the upcuts can lift the piece.
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