Holding Inlay material

[kiinstructor]

I have a couple of questions on holding inlay material while you cut the male parts. What I have been doing is taking a piece of 3/16 material or slightly over and lightly gluing it with 5 min epoxy to another piece of wood that is help on my vacuum table. I was doing 1/8 inlays but found that they were a bit shallow so I do 3/16 and sometimes .25. Anyway what I do after I cut the male parts is to pry the inlay piece off, comes off rather easily and then sand the back until the pieces come out. Kind of a pain in the butt but I was hoping I could get a few other ideas, there must be a better way. Also how many thousands over do you make the butt before you inlay. Appreciate your input and thanks.

Happiness
Mark

 

[rhncue]

I have a couple of questions on holding inlay material while you cut the male parts. What I have been doing is taking a piece of 3/16 material or slightly over and lightly gluing it with 5 min epoxy to another piece of wood that is help on my vacuum table. I was doing 1/8 inlays but found that they were a bit shallow so I do 3/16 and sometimes .25. Anyway what I do after I cut the male parts is to pry the inlay piece off, comes off rather easily and then sand the back until the pieces come out. Kind of a pain in the butt but I was hoping I could get a few other ideas, there must be a better way. Also how many thousands over do you make the butt before you inlay. Appreciate your input and thanks.

Happiness
Mark

I buy 1/8 inch 4X8 ft hardboard for less than 5.00 a sheet. I cut this into 3X12 inch pieces so I get 128 pieces. I then drill a 3/8 hole at each end 11 inch apart. On my table I have two tapped 1/4-20 tapped holes so that one of these boards can be screwed down. Now I just use 3M spray contact cement on both the hardboard and the inlay material surfaces, wait 10 minutes or so and then stick them together. I have a cabinet with partitions where I have many dozens of these inlay/boards already glued up so that what ever inlay material I need I just pull out for instant use. These boards of hardboard are cheap (about 4 cents each) sacrificial substrate that the cutter can cut into a little with no harm to the cutter nor the table.

After cutting my inlays I just use some "auto wax wash" which is a paint prep liquid used to clean a body before spraying and run some into the cut lines for the inlays. This stuff seeps under the inlays and dissolves the glue so that the inlays just fall off of the board. I then drop the inlays into a jar of wax wash to clean the parts of what's left of the dissolved glue before use.

Dick

 

[Sheldon]

I typically use very dry 2x4s. Cut them to 12" lengths, run them through the planer, and glue my inlay material to that. Once they are cut, I run the whole thing through the bandsaw leaving just a sliver of the 2x4, then sand until I can remove the inlays individually. I have a little table that I inlay off of, that I can remove from the CNC. It's got holes in the underside of it for screws, which I can secure the 2x4 to it with. I only do this if I am doing muliple inlays (cut/glue/cut) before removing the thing from the CNC. Most of the time I just use spring clamps.

 

[macguy]

I have a couple of questions on holding inlay material while you cut the male parts. What I have been doing is taking a piece of 3/16 material or slightly over and lightly gluing it with 5 min epoxy to another piece of wood that is help on my vacuum table. I was doing 1/8 inlays but found that they were a bit shallow so I do 3/16 and sometimes .25. Anyway what I do after I cut the male parts is to pry the inlay piece off, comes off rather easily and then sand the back until the pieces come out. Kind of a pain in the butt but I was hoping I could get a few other ideas, there must be a better way. Also how many thousands over do you make the butt before you inlay. Appreciate your input and thanks.

Happiness
Mark

I have had good success with just a good quality double faced tape. Another technique if you are making wood inlays is to cut a small slab of the piece of wood you are using , cut in a bunch of inlays then with your band saw slice off the back of the wood and the inlays will just drop out.

 

[CueCaps]

After cutting my inlays I just use some "auto wax wash" which is a paint prep liquid used to clean a body before spraying and run some into the cut lines for the inlays. This stuff seeps under the inlays and dissolves the glue so that the inlays just fall off of the board. I then drop the inlays into a jar of wax wash to clean the parts of what's left of the dissolved glue before use.
Dick

Richard,
The "auto wax wash"..
What was the brand and name of their product?
I was using carpet tape (Doubleback) and then 70%
Isopropyl alcohol. The glue turns gummy after the alcohol
evaporates..
Yours seem to leave less residue to mess with..

As for the prying, I hate to pry-off inlays with thin sections.
They tend to stress the thin parts and I've cracked a couple of propeller
paddles off..

Thanks,
Alton

 

[scdiveteam]

Hi,

We clamp .225 thick inlay slabs to the table and after the milling we put them through a drum sander face down sanding the bottom on the slab and they come out perfect.

Rick

 

[kiinstructor]

Never heard of auto wax. If it doesnt hurt the inlays, that sounds like the method. Where can I get the stuff Dick. Also are most of you making 1/8 or 3/16 inlays? I know with some material 1/8 may turn thin on the edges after turning and with opaques, it might look thin. Dont think you run into that problem with most woods. But maybe with Ivory. Thanks for all the tips.

Mark

 

[rhncue]

Richard,
The "auto wax wash"..
What was the brand and name of their product?
I was using carpet tape (Doubleback) and then 70%
Isopropyl alcohol. The glue turns gummy after the alcohol
evaporates..
Yours seem to leave less residue to mess with..

As for the prying, I hate to pry-off inlays with thin sections.
They tend to stress the thin parts and I've cracked a couple of propeller
paddles off..

Thanks,
Alton

The brand that I use is called Prep-Sol. There are a number of different brands but this seems to be the cheapest. Any auto-supply should carry some especially if they sell paint or body supplies for cars.

Dick

 

[rhncue]

Hi,

We clamp .225 thick inlay slabs to the table and after the milling we put them through a drum sander face down sanding the bottom on the slab and they come out perfect.

Rick

What size cutters are you using? I use .0312 which is 1/32. They only cut around .135 or so deep before the cutter gets larger. I usually cut my inlays about .150 thick which puts a very slight bevel onto the inlay so that it starts in the pocket a little easier but then fills the pocket tightly. I make sure that my inlays are not wider than .625 so that they don't wipe out on the sides.

Dick

 

[kiinstructor]

I also use .312 cutters but I am able to get as much as .25 from them. Mostly .1875 though. I set the feedrate slow and take my time. So if a part takes 1.5 minutes instead of 45 seconds. Wont stop the world from turning. I use Mastercam and the automatic feedrate is about 6.5 inches/min. You can set it as high as you want but that works fine for me. Anyway Im going to try both the double sided tape and the spray adhesive method and see what works the best. Thanks for all the input I appreciate it very much.

Mark

 

[rhncue]

I also use .312 cutters but I am able to get as much as .25 from them. Mostly .1875 though. I set the feedrate slow and take my time. So if a part takes 1.5 minutes instead of 45 seconds. Wont stop the world from turning. I use Mastercam and the automatic feedrate is about 6.5 inches/min. You can set it as high as you want but that works fine for me. Anyway Im going to try both the double sided tape and the spray adhesive method and see what works the best. Thanks for all the input I appreciate it very much.

Mark

Where are you getting your cutters? The reason I ask this is that the cutting length of most smaller end mills is three times their width which is actually a little smaller than an 1/8. I have no problems with breaking the small bits it's just that they don't cut deep enough. I use the fish-tail bits from Precise bits and if I try to cut through .175 the bit would probably just pull the material loose as I would be trying to cut with the round shank.

Dick

 

[Sheldon]

I run .050 cutters 90% of the time at 25-40 IPM.
I clean up the tips of pockets with a .020 or a .015. I've learned to use them very sparingly.
For long forearm points, I put the forearm in my cnc so that the centerline of the forearm is level. (normally the top outside edge is level) This puts my tip about .06 lower than the base of a 9 or 10 inch point. Set your depth at .14 at the base, and your cutter will only go .08 deep at the point. So your short l.o.c. bit wont bury when you clean up the tip. The depth of the inlay works out about the same, depending on the width you go with at the base, considering that the wider you go, the shallower you are cutting, due to the radius.

 

[brianna187]

Hi,

We clamp .225 thick inlay slabs to the table and after the milling we put them through a drum sander face down sanding the bottom on the slab and they come out perfect.

Rick

this what we do also its the quickest and easyest way to do it and the parts are perfect every time

 

[kiinstructor]

Dick, I got my cutters from Blud many years ago. They have a .25 cutting length. I also have some that I bought on Ebay and they have a .1875 cutting length. Both work well. I use a slow feedrate. Whats the difference if the pocket takes 2 minutes or 1 minute. I just want it clean and done right. My spindle has less than a thou runout so Im good to go there. Im just beginning Inlay work and there is alot to learn. Im thankful that I have this forum for help. My drawing and posting program is Mastercam. An older version 8.1 but it is still complicated and there is a huge learning curve. I have found some good advise and techniques from Bob Dzurick regarding programming Mastercam. He walked me thorough a simple part and pocket to get the feel of it and help me post it. Part worked great only really tight. Need to leave a little clearance in the pocket. Now Im hooked and have design over 15 parts and ran 8 of them successfully. Bob also gave me advise on running multiple parts instead of just one. This saves alot of time. I can see the tight sharp point is where the artistry comes in. I dont understand the part about cleaning up the points with a smaller cutter. Do you have to run a seperate program for that?

 

[Sheldon]

I dont understand the part about cleaning up the points with a smaller cutter. Do you have to run a seperate program for that?

No, but you will have to program in a tool change, or a M00 to stop the program so that you can switch tools. I'll try to find you a picture that gives you an idea how to get it done....

 

[Sheldon]

Let me know if this doesn't make sense to you....
The red and green lines are the drawing, the blue lines are the cut paths.
Pocket with .05, then I do the .02 straight up into the corners, then the tiny pockets at the tips, then a cleanup pass all the way around. I leave about .003 on the sides with the .05, so the .02 is just barely cutting on the cleanup path. The little pockets at the tips are also offset a couple of thousandths, allowing the cleanup pass to cut material all the way around, for a nice clean pocket.

 

[cueman]

I cut up a sheet of 1/8" plexiglass into 3" x 12" pieces. Then I super glue the inlay slabs down to the brown paper that covers the plexi glass. I cut barely through inlay and the paper and when done I just pop them off. If the parts are the same on both sides I just flip the inlay over and put it into the pocket upside down. If it is not the same on both sides I sand the paper off the bottom of the inlay and glue it in.

 

[DanO]

OK I’ve had good success using epoxy to hold down phenolic, synthetic stone and bone. For holding wood I’ve tried 3M spray adhesive, and double face tape with terrible success so far. Before I pop for a drum sander and do the sand the back trick, is their any other method of successfully holding WOOD for inlays? I could try Cueman’s plexyglass approach but it sounds like the drum sander is the most proven approach.

 

[Jr's Farm]

My process:
I've been attaching a sacrificial substrate to my table first. I then put a 3/4" router bit in and mill the surface down a couple thousanths, ensuring a flat surface that is parallel to the plane of the spindle.

For smaller inlays, I cut a blank just big enough for all the parts I'm cutting. I then place some sticky masking tape to the back side, using a roller to press it firmly in place. I then superglue the tape side to my sacrificial board.

Depending on the size of the parts and the type of material, I'll usually cut to within .002 +/- of cutting through, leaving an "onion skin" keeping the part attached. Getting the right thickness on the onion skin will allow you to just pop the pieces out. I'll take a thin, flexible putty knife and separate the part blank from the tape, which stays attached to the superglue, attached to the substrate.

One benefit of surfacing the sacrificial board in this way, is ensuring that the onion skin is uniform in thickness. I'll indicate my tool on the surface of the sacrificial board, zero the Z axis, jog the Z to my material thickness, and then zero my Z again, setting the Z zero to my part height.

There are probably better ways, but so far I've had great results. YMMV.

Regards,
Frank

 

[DanO]

Thanks Frank, I like your input of zeroing your Z plane before gluing down the onion. I ran an indicator across my clamp bed and I'm within .002" over 12" but odds are very high that the sub board is not parallel. I never thought the hardest task to cnc was going to be holding the dang material down!