[bigred8080]

This is one my first project, kinda one of those "HA I told you I could do this" kinda things for a guy I work with. It is cut out of a scrap piece of MDF (i know i know thats part of my problem) some of the Letters were ripped off during the finishing pass. What can I do to help hold them together? Ive tried using a harder wood, and it still flakes off on the I's and L's. I tried using a differnt font, or bolding it up and that didnt work. Then i tired making it bigger. I started out at 1/2'' letters, I had to go up to 1 or 1.25 to get it to hold together.

Any other ideas

[ger21]

A picture would help, but try taking very shallow passes, even .01 or so. But if the parts are really small, and you're using MDF, there's really very little that you can do.

[jm82792]

I just did some smaller letting that was .25" or so tall(for the smaller case letters).
It looks good enough, not perfect but for basswood it worked. Maybe you can cheat and paint the MDF so you scratch the coating off? ....if you can use something rock hard like Ipe since it holds detail very nicely.

[bigred8080]

Yeah I knew a picture would help. I was at work at the time and my computer wasn't cooperating.

[louieatienza]

Do it as a V-carve with a flat depth, with a 30 degree bit, and use the bit you're using as the clearance tool. The extra meat under the letters will help hold them together, and they'll still look small....

Another option would be to use plastic or PVC board.

Although aluminum, I used a similar technique here (you can see how small the serifs are, the letters are 5/16" tall by 1/8" total depth:

[adprinter]

This is one my first project, kinda one of those "HA I told you I could do this" kinda things for a guy I work with. It is cut out of a scrap piece of MDF (i know i know thats part of my problem) some of the Letters were ripped off during the finishing pass. What can I do to help hold them together? Ive tried using a harder wood, and it still flakes off on the I's and L's. I tried using a differnt font, or bolding it up and that didnt work. Then i tired making it bigger. I started out at 1/2'' letters, I had to go up to 1 or 1.25 to get it to hold together.

Any other ideas

With MDF, it's already saw dust before you even begin cutting. (cause that's what it's MADE of). For any sort of precision carvings, I have learned that hardwoods are the ONLY way to go. You might try slowing down your feedrate. Even solid Oak can split and break when narrow, thin areas of letters are SLAPPED by a router bit turning at 27000 RPM (and the feedrate is set above more than about 10 inches per minute). I.E. the tool needs TIME contacting the work, for the cutter to do it's thing (Let the little dog EAT). I have gotten some pretty good results, by taking very shallow depth of cut per pass, and running multiple passes to the desired depth of cut. However, 1/4" font height just ain't happening, even in Oak. The tooling size it would require to preserve any sort of recognizable font detail, would be so small, that it would probably break the bit immediately (Oak is right up there with metal, in terms of density).

[jm82792]

Everybody forgets Ipe(well it's not available like douglas fir), it's decking material that is rather nice for some things.
Ipe has a Jhanka Hardness of 3684
White Oak has a hardness of 1360
I've engraved Ipe with a .125" 30* V bit at about .03 deep at 12 IPM at 35K(might be too high RPM wise), it holds detail well.
Might not trick your friend though For instance I gave my friend an Ipe sign and he thought it was plastic since it can be cold to the touch like stone, and rather dense.

[adprinter]

Everybody forgets Ipe(well it's not available like douglas fir), it's decking material that is rather nice for some things.
Ipe has a Jhanka Hardness of 3684
White Oak has a hardness of 1360
I've engraved Ipe with a .125" 30* V bit at about .03 deep at 12 IPM at 35K(might be too high RPM wise), it holds detail well.
Might not trick your friend though For instance I gave my friend an Ipe sign and he thought it was plastic since it can be cold to the touch like stone, and rather dense.

I don't think he was referring to engraving, but carving in 3D (RAISED lettering). There is a BIG difference between to two operations.

[Pplug]

How about a laser engraver? That would give you exceptional detail at even smaller sizes.

[Dylwad]

Soak the letters in thin super glue before the finish pass and use a down cut bit.

[jm82792]

Yes I did mistake engraving with raised lettering
But I have worked extensively with Ipe, and think it would work.

[mrmfwilson]

What size are the letters in the picture? Do the letters need to be so deep? Try reducing the height. It also looks like you need to use a smaller bit because the A and D did not complete. Depending on the bit size, talking about 1/8 inch bits or less, cut something like that at 25ipm or less in MDF with a step down about half the bit diameter to help with the letters chipping and breaking. Using a v-carving routine will also help because the base of the letters will be larger than the top. If you don't have a v-carving routine you can do a profile with a v-bit. Just offset the bit to create the correct size letters.

Attached is a rendering from m
y software with something like you are doing. This is a 12" x 6" sign with 3/4" lettering. I went with 1/4" tall lettering because my 1/16 inch bit only has that much cutting depth. I'm not sure what size bit you are using but I had to go to a 1/16" bit to get proper the detail in the software. If you go to 1' or 1.25" inch lettering you might get away with a 1/8" bit but the sign gets bigger also.

It looks like this is an old thread but for some reason it turned up as new on my list. I went ahead and tested the lettering that I made. It worked at 30ipm. I jacked it up to 45ipm at the end and it broke one of the "I"'s. I broke two more letters trying to correct the part where the material wasn't level. Definitely hard to achieve and the letters are fragile. My advise to someone that wants to do thin lettering like this on MDF is to keep the height small and make the letters as fat as possible. Use a sealer before the last pass for security. Or use plastic material.