[posix]

Here are a few pictures of what I'm getting. They are not that great, my phone camera cannot focus properly at short distances. The first picture is of the cutters I'm using, 3mm, 4mm and 6mm upcut spiral, they are not very long as they are more for steel than wood. Those are the only upcut spiral bits I could find.

Don't be fooled by the wood grain, it IS a sandwich of 18mm chipboard, 3mm MDF on top and then veneered with 0.8 (?) veneer.

I spin the tool at 10000rpm. If I run at 2500mm/min then I get a fuzzy cut, if I run at 5000mm/min then I get a horrible cut. If I go at 500mm/min then I get, well a long "molten"-looking thread instead of chips.

If I spin the tool at 15000rpm I'm not getting any better results.

Can someone with lots of experience give their comments please.

[ger21]

The pictures are a bit hard to see. First thing I see is that it looks like your machine is flexing quite a bit, as the cuts don't appear to be very straight? The solution to that is to take lighter cuts.

Next thing I'd suggest is to try different tooling. I'm thinking your bits aren't very sharp. Anything with veneer on it will not cut well with an upcut spiral, unless it is extremely sharp, as in never been used before sharp. Even cutting just mdf, if it's not really sharp, you'll get a fuzzy edge at best with some mdf. Cut quality can vary among different mfg's.

Switching to a downcut spiral should give you a clean edge. At 10,000 rpm, try about 2500-3000mm/min with the 6mm bits. No more than 14,000rpm.

For the smaller bits, use the same feedrates, but start at 14,000rpm.

Bottom line, though, it to use a downcut bit, and take lighter cuts if needed.

Some better pictures might help as well.

[posix]

The pictures are a bit hard to see. First thing I see is that it looks like your machine is flexing quite a bit, as the cuts don't appear to be very straight? The solution to that is to take lighter cuts.

Yes it's flexing and the cuts are already light as is - 1mm to 3mm deep. If I go 0.5mm then I get those "molten" threads I was talking about. Plus my router is only 750w so it doesn't have the grunt needed for anything deeper and/or faster.

Next thing I'd suggest is to try different tooling. I'm thinking your bits aren't very sharp. Anything with veneer on it will not cut well with an upcut spiral, unless it is extremely sharp, as in never been used before sharp. Even cutting just mdf, if it's not really sharp, you'll get a fuzzy edge at best with some mdf. Cut quality can vary among different mfg's.

The 3mm and 4mm bits are brand-new sharp, the 6mm has been used on a smaller router - that's in my bedroom - for a few days. Is it possible for these HSS bits with the yellow coating (titanium tungsten strontium unobtanium coating I presume, with a bit of dilithium and gold pressed latinum thrown in for good measure) to dull in an hour or two worth of cutting?

Switching to a downcut spiral should give you a clean edge. At 10,000 rpm, try about 2500-3000mm/min with the 6mm bits. No more than 14,000rpm.

For the smaller bits, use the same feedrates, but start at 14,000rpm.

Bottom line, though, it to use a downcut bit, and take lighter cuts if needed.

Some better pictures might help as well.

Ok, these 3 upcuts were the ONLY spiral bits I was able to find. When I ask for "spiral bits" peoples eyes usually glaze over. I do have one 6mm straight bit. Would the same feed rate still hold true for those?

I have noticed that my v-bit cuts nice and clean.

I'll try and get better pictures too.

Thanks ger!

[ger21]

Try the straight bit, but go a little slower.

I've never used a HSS bit, but they supposedly dull very quickly.

[tobyaxis]

Try the straight bit, but go a little slower.

I've never used a HSS bit, but they supposedly dull very quickly.

HSS dulls very fast in Fibrous Materials. I would say to find a Coated End Mill for this, but I have no clue as to which coating would work best in this material. LOL, I've never cut this stuff before.

[ger21]

You don't need coated, just plain carbide. You typically won't find coated tools in the woodworking industry, unless possibly highly specialized applications.

[eSilviu]

Here are a few pictures of what I'm getting. They are not that great, my phone camera cannot focus properly at short distances.

put a magnifier glass (5x, 10X) next to phone camera. then you can picture even the *** of ants.

[tobyaxis]

You don't need coated, just plain carbide. You typically won't find coated tools in the woodworking industry, unless possibly highly specialized applications.

Is there a Tin Coating for Wood working tools??

I am thinking the same thing you mentioned about his feeds and speeds, "Slower and Lower".

[Big-tex]

Is there a Tin Coating for Wood working tools??

I am thinking the same thing you mentioned about his feeds and speeds, "Slower and Lower".

No there are not used coated tools. I have been in woodwork for 20+ years did not use coated tool once in CNC, hand held router etc.

[Rico55]

You stated the solution to your problem in the first line of your post; the bits you are using are made for steel, and not for wood. The glue in MDF is very abrasive, and will dull steel tools very quickly- I would never use anything but solid carbide when cutting MDF.
You will probably have to get your tooling from an online supplier like McMaster-Carr, Discount Tools or Rutland Tool, among others. C.R. Onsrud makes excellent but expensive tools, and has some good information about types of tooling in their catalog. I just got some good quality bits from Discount Tools, and their pricing was very reasonable- the bits were also American made, which I think is important for quality and economic sustainability. I would be using a two-flute, downcut, solid carbide bit for what you are doing, and probably use a .25 inch diameter for less cutting resistance on your machine. Use a small depth of cut, with multiple passes at the highest R.P.M. that your machine is capable of.
Normally, you would use a downcut bit when cutting a veneered panel, with the veneer on the upper face, to keep from splintering the veneer. Depending on how deep you are routing, sometimes the downcut bit tends to pack chips and/or dust into the cut, and contribute to dulling the cutter. You can alleviate some of this chip buildup by using compressed air to clear the debris away from the cutter- this will also help cool the tool, and prevent overheating and dulling. If your sandwich can be turned over, and you can cut down through the material into a spoil-board (about .003"), you will minimize chipping on the good face with an upcut bit. If you need to use an upcut bit with the veneer up, take a very light cut at high R.P.M.s to just break the surface of the veneer, and then another pass or two to depth.
The first step is to get the proper cutting tool, and then experiment a little bit to find the best speeds and feeds, which will depend on your machine.

[posix]

Thanks rico for your detailed info. The problem lies in the "first step", I thought I had the proper cutting tool and was experimenting. Well, little did I know that my experimenting was giving me the wrong results as my bits were dulled so quickly! Ugh!