Is this how it's done?

[Dranos]

I have a project involving letters cut from 1/2" thick PVC. The letters are 12" tall and need to be installed with a 1/2" space from the wall. Here is the procedure I have planned, please correct me or suggest a better way if I'm wrong.

Set up letters mirrored (flipped) in illustrator.
Load into part works and set points for drilling holes that the studs will screw into.
Set the cut path then send to Shopbot.
Have the machine drill first then change the bit and allow it to cut the letters out.

Well that's my plan. Is that how letters are done? I've never done this before so I only have a theory.

Any advice is appreciated.

[Big-Tex]

Here is what I can suggest.
I would cut letters right side up with o-flute bit.
Than with same file just down spiral and drill bit I would cut say 1/4" mesonite for template. Use template for drilling holes for studs into letters and wall as wall.

This will give you same stud layout or at least pretty close.

I am sure others have other suggestions, just be open to ideas, life is one learning curve.

[bleeth]

I would cut the letters the right way, make the template, and use the template as a guide to glue the pegs to the PVC. You didn't mention what material you want to make the pegs in but just about whatever it is there is a good epoxy that will do the job.
Check out how the professional letter companies like Gemini do stand-offs.

[robtown]

Do it how you plan. Use an 1/8" bit to drill stud holes, then cut out. I have a plotter so I can use the same file used for cutting to make a paper pattern.

For the studs I use aluminum studs from McMaster Carr, I think it's either 8-32 or 6-32, but they fit nicely in the 1/8" holes with a small dollup of epoxy for holding power. I use the alum studs because I can clip them easily if they are too long. you can also buy spacers from mcmaster...

[Dranos]

Thanks for the help so far. I do have one problem though. In my ignorance I purchased a bunch of 3/16 (10-24) studs from Gemini. I am yet to purchase the correct bit for drill the matching holes.
One guy at Onsrud says that I need to search for a tap before I buy the bit. Now I'm all confused.
How can I make the best use of what I've purchased?
Which bit will make the coorect size hole for the 3/16 studs I already purchased?

[scootie]

Dranos,
Everyone has their favorite way, we cut a lot of PVC letters and here's what works for us.
Cut/rout the letters as usual.
Create a paper pattern (we use a plotter) if you don't have one, space/kern the letters out on a piece of paper and trace around them.
Lay the letters face downand place the pattern over them, align them one at a time and use an awl or sharp pointed nail to punch through the paper and leave a mark on the back of the letter. Now you have a mounting pattern that matches exactly for your stud positions.
We use the Gemini 10-24 studs so an 11/64" drill is correct hole size.
Holes are made on a drill press, you can set the depth to avoid going too deep. On 1/2" material go about 3/8" deep.
Lay the letters on a smooth clean table and drive the studs in with a small hammer, yes, drive them in. You do not have to tap threads in PVC. If you're concerned with holding power just try to pull one out, the PVC closes around the threads in the hole and clamps the stud in place.
The studs make finishing the letters easier too, you have something to hold them with. We press the letters onto scrap foam to hold them for spray finishing.
Remember, if you have one or more letters of the same character to mark them, we usually mark the letters from one thru (?) and also mark which is the top of some symetric letters so the customer knows which way is up and doesn't try to force wrong letters in the right mounting holes.

Larry,,,,

[Dranos]

Sounds good but I do not have a plotter or a drill press. What issues would I face if I layout the letters mirrored and use my shopbot for drilling first?
As for the plotter issue, could I tape down some paper onto a smooth sheet, put a pencil in the spindle and have it draw the letters properly spaced out with marks for drilling?

[Big-Tex]

Here is alternative to templete method.

Just cut letters and mount studs.
Mark stud ends with magic marker and touch wall in location where you want to install it. You will see marker dots on wall, that is where you drill. :)

[jerry_stanek]

You will want some sort of template for the drilling in the wall so you can get the spacing right and also level. You can chuck a magic marker up or call widget works and order his plotter pen set. I have one and it comes in handy for lots of things. I plot out pre printed signs by taping a sheet of news print over it and run the file to see how close my file is to the one that is printed.

[maxheadroom]

'everyone has their own method....', true, but man, this is not rocket science....... and if you have a router why not use it to it's full capability???!!!

Adrian, you are right in your assumption: flip the letters in the computer in X, drill the holes in the back then cut the letters out - face down.

Here's what I've done for more than a decade, all on the CNC: fast, accurate and efficient:

1. In your design software, place a 1/8" circle within each letter, use a minimum of 3 holes for most letters, 2 on the 'I' or 'l', 4 on larger letters. If you have many instances of the same letter add the circles to one letter only, make copies of that one to match the number you need. Delete the others that do not have holes.
NOTE: the reason for using the same hole configuration for all letters is that they are the same is that you don't have to be concerned on mixing the letters up, the drilling configuration on all is identical.
2. Place a sheet of 1/8" masonite or particle board with the words properly spaced on the cnc. Engrave a base line reference point, then using an 1/8" end mill select 1/8" holes and drill through. Mark this pattern as seen on the router 'back'.
3. Place the 1/2' PVC on the router, drill only the 1/8" stud holes on the letters 3/8" deep with the same 1/8" - face down.
4. Use a 3/16 or 1/4" end mill route the letters - face down. You may need bridges applied to the letters to keep them from moving.
5. Remove and clean the letters. Try inserting a stud into one of the mounting holes, it should screw in easily with the use of pliers, if it's too hard, use the next largest fractional bit, chuck it into a cordless drill. Apply a piece of tape 3/8" from the tip of the drill bit. Drill the holes on the back of each letter to 3/8" depth, no deeper. Do only one at first, and don't rush it, doing so will punch through the face.
6. Using the studs you've already purchased, screw into the pvc. It may require pliers to cinch it down but you'll know when you try.
NOTE: you do not have to tap the holes, using the studs as described, in PVC the studs will self tap into the soft pvc as you install the studs.
7. Finish enlarging the other holes if required.
8. Transfer the base line to the opposite side of the masonite marked back (it's the back of the pattern / letters. Tape the masonite template on the wall with the side 'back' facing the wall, using the base line as the level reference. Drill w/ cordless drill 1/8" bit through the holes into the wall - this will work if the wall is sheet rock. If it's exterior into brick, etc, use the template and a sharpie to mark the hole location, remove template then using the appropriate drill motor / drill size / type, drill slightly undersized, clean holes, insert silicon, insert letter tapping in w/ a dead blow mallet.

The only thing I'd do differently is that I'd make a paper pattern because I have a plotter.

I would also suggest using a scrap of pvc and doing a test first, which will demonstrate it works as described. It also allows you to make adjustments on scrap before committing to the final run.

What I've outlined is a no brainier, period. I've done thousands of letters this way..... not bragging, just stating that this is a proven method of getting the job done, period.

Since the purchase of a CNC over a decade ago, my table saw, drill press, and hand drills are used considerably less. The CNC will do everything described, using as anything less is using the cnc as an expensive jig saw.

[beacon14]

I'm glad Walter said it so I didn't have to. I'd only add that I'd do a few test holes on a scrap area to be sure the holes from the CNC will work without having to be enlarged by hand. A few minutes of testing will determine the best hole size and mounting method for the hardware you have on hand.

The more work that can be optimized onto the CNC, the more you are getting your money's worth from the machine.

[rb99]

You could get someone with a plotter to make the paper pattern...



RIB

[maxheadroom]

David, I did suggest a test, however I think I know where he's coming from. I'm guessing that he has limited tooling, and as this is a first in cutting this type of job, wants to use what tools he has on hand, all within his shop, including the pattern.

That's completely understandable, as many of us have been in that position, and not wanting to pay someone to make the pattern. At less than 8 bucks a sheet for 1/8 template material, he'd be hard pressed to get someone to do the pattern for that price.

That being said, for a 10-24 stud the proper drill a no 25 drill bit - .1485, not only a bit most shops don't have, but don't have a drill chuck that can be used on the CNC.

To achieve that you'd..... uh oh, ok back track a bit. To achieve a .1485 hole draw that size hole in the software, in conjunction with an 1/8" bit (I was thinking the hole needed to be under 1/8", not), run a area clearance in offset and he's set. You're right, he'll need to do a few tests to make sure the hole size is right not only in the software, but after routing.

PVC, either drilling or clearance path, PVC will heat up during machining, and in cooling down, the pvc will relax a little making the hole smaller. Adjustment would be made by enlarging the test hole by a few thou till the stud could be inserted.

But a few test samples could have been completed in less time it took to write all of this.

Hopefully he'll get it done, and posts positive results.

[Dranos]

Thanks alot guys. I have to wait a couple of weeks for the supplies to reach me in Jamaica. As soon as I get the studs and bits I will do some tests and let you know how things work out.

This forum is truly helpful.

[jerry_stanek]

You could get someone with a plotter to make the paper pattern...



RIB


I went to a small news paper and got the end of a roll of news print. They gave it to me the I bought the plotter pen set from Russ Todd at widgetworks. All together it was under $50. Now any tiome I need to make a template or want to see what a cut will look like I just trow the pen in the router and run a file.