Sled problem

[rbrown]

I'm doing a 6' x 12" X 5/8" shelf with grooves cut in them and I made a sled 6' 7" x 14" of 3/4 mdf. I built roller supports to in case it flexes (it doesn't) and it is having a hard time measuring the board. It moves to the end of the sled then it moves an inch then back an inch then moves back and forth in smaller and smaller increments until I stop it... So is the sled too heavy or is the brass roller slipping on the mdf or do I have some other problem? Has anyone done something this big and can give me some ideas? It only has a couple of hours of cutting time on the machine so I don't think it is whipped. Thanks, Bob

[badbert]

Couldn't you just add 4" pieces to each end. Or make 1" wide 5/8" thick 6' 8" rails and attach them to the sides. The weight of the sled and the board, is pretty heavy. Also squaring it up in the machine becomes very important. At the very least use masking tape on the bottom of the board or sled where the brass roller contacts. And a few more to add traction.

[aokweld101]

I'm no expert but my thoughts are is if its a .625 thick then its in it's parameters if you support the ends I wouldn't think it would matter about useing a sled.

[bergerud]

I have had the jogging back and forth before and chalked up to software. Rebooted and it stopped. It may not be software, it may be your sled slipping on the belts. Mdf is too smooth. Try some masking or duct tape on the underside for the belts to grip.

[fwharris]

I have had the jogging back and forth before and chalked up to software. Rebooted and it stopped. It may not be software, it may be your sled slipping on the belts. Mdf is too smooth. Try some masking or duct tape on the underside for the belts to grip.

From the conference they talked about the the jogging back and forth thing. What they stated is the machine is calculating/looking for any slop/play in the x gear movement compared to the board tracking system.

I agree that maybe the mdf might be to heavy and slick for this long of a board and when it is at the end it could very possibly be raising the board up and loosing contact with the brass roller. I would go with either a lighter sled material or like stated since the 5/8" board is thick enough just go with that with added width and length...

[liquidguitars]

the jogging back and forth thing. What they stated is the machine is calculating/looking for any slop/play in the x gear movement compared to the board tracking system. Normal as the board is moving off the brass roller at the end of the board measurement. But any back and forth in the center of the board as it runs is VERY bad and can do damage to the x drive. BTW why would you only use 3.5 on each end of a sled? most of us have documented over 4" or 6" extra is much better.

[Digitalwoodshop]

It is my belief that your rocking back and forth quickly is the result of the board loosing contact with the brass roller. Yes, the machine does the back and forth calculating the GEAR SLOP or LOST MOTION between the X Gear Box and the Actual Board as measured by the brass roller... Or even the board only being held by ONE ROLLER and Lifting...

It is my guess that the board it Drooping at the far end causing the board to be lifted off the brass roller. Yes, you used roller stands but try adjusting it higher.

Masking Tape on the Brass Roller path might be good too...

And since this is a 6 foot board, I would use PLACE on END and add a 4 inch dead area on the right side of Designer... OR even start with a 6 foot 8 inch board and cut off the 4 inches when done. IF the board is only being held by ONE roller when the board is doing it's DANCE then you have found the problem.... A 6 foot 8 inch board and place on end would be the best way to setup this project.

Here is a sample board. 6 Foot 8 inches long and I put 2 four inch boxes on either end and put the artwork between the blocks. Keep in mind the Brass Roller is at the TOP of your SCREEN. and if you are designing the bottom of the board the Brass Roller is on the bottom of the screen and everything is up side down.

AL

[DickB]

It is my guess that the board it Drooping at the far end causing the board to be lifted off the brass roller. Yes, you used roller stands but try adjusting it higher.
I'm with Al on this one as a likely cause. You might think that once you got your rollers adjusted that would be it, but I have found small differences in boards and sleds that have required different setups for the rollers. The machine's rollers as well as the auxiliary rollers should be addressed. BTW I had trouble adjusting the machine's rollers so I use a bit different setup that works well for me:

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As you are having difficulty, I would recommend that you try measuring the length of the board before running your project. If you loose contact in the middle of the project it may be difficult to recover. If you can measure the board successfully a couple of times (raising the head between measurements) you should be good to go.

[mtylerfl]

... I use a bit different setup that works well for me:

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THAT is a very nice setup! Very, very secure and accurate for long-board projects! Thank you for sharing that idea - it's a great one.

[aokweld101]

I'm looking at DickB set up,.. on your rollers did you buy them or make them, If it is to much to buy them, I could make them myself using aluminum for the rollers and steel for the mount ...and if you bought them... where?

[CNC Carver]

I use these as supports http://www.harborfreight.com/132-lb-capacity-roller-stand-68898.html

[fwharris]

Normal as the board is moving off the brass roller at the end of the board measurement. But any back and forth in the center of the board as it runs is VERY bad and can do damage to the x drive. BTW why would you only use 3.5 on each end of a sled? most of us have documented over 4" or 6" extra is much better.

LG,

I was just stating what Chris Rawls told us at the conference :D:?: when the question was asked. He did state that this usually occurs in older machines do to the wear on the gears..

HHHMMM must be someone else on the 3.5" as I do use 4"...:-P

[liquidguitars]

No worries Floyd there are two types of "dancing" one at the end of the measurement that not a issue and one that's bad done in the middle of the board. if that make sense...
HHHMMM must be someone else on the 3.5" as I do use 4"...http://forum.carvewright.com/images/smilies/icon_razz.gif I think we know who that is... :)

[fwharris]

No worries Floyd there are two types of "dancing" one at the end of the measurement that not a issue and one that's bad done in the middle of the board. if that make sense... I think we know who that is... :)

Oh I know!!! ;)

[badbert]

Ok why would the X-drive go backwards? I agree it is possibly losing the brass roller. But wouldn't it just continue forward? I do understand we are talking two different kinds of back-and-forth. One, when the machine reaches the end of the board it goes back and forth to measure the end. Two, if the board is tapered, or warped, or twisted, the effort needed to move the board becomes excessive and the x-drive stalls and starts a back and forth motion that loops until you stop it. I believe the second is the case here. Just to prove the theory... put the board in without the sled and use measure. Something is causing the increase in effort to move the board.

[fwharris]

Ok why would the X-drive go backwards? I agree it is possibly losing the brass roller. But wouldn't it just continue forward? I do understand we are talking two different kinds of back-and-forth. One, when the machine reaches the end of the board it goes back and forth to measure the end. Two, if the board is tapered, or warped, or twisted, the effort needed to move the board becomes excessive and the x-drive stalls and starts a back and forth motion that loops until you stop it. I believe the second is the case here. Just to prove the theory... put the board in without the sled and use measure. Something is causing the increase in effort to move the board.

From what I got from Chis is that as the board in moving the computer sees the movement of the brass roller and compares it to the X movement. If it finds a difference then it does the jog back and forth to determine the slop in the X gears...

[mcQ]

When you carve a part over about 3 - 4 ft you need to use outfeed tables on each end to support your workpiece. Even though you added 3 1/2" to each end of your sled which keeps the sled under the rollers the length of the board hanging out the ends is prying the compression rollers up and probably causing the sled to loose contact with the tracking roller. Also carving a project this long without support is asking to break the short tables on your machine.

Erwin
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[DickB]

I'm looking at DickB set up,.. on your rollers did you buy them or make them, If it is to much to buy them, I could make them myself using aluminum for the rollers and steel for the mount ...and if you bought them... where?I bought them MANY years ago as an accessory to a folding Ryobi Quick Stand. That stand is no longer in production, although Ryobi now sells a totally different stand under the same name. The original accessory included camps to mount a 2x4 under the table, and the rollers slipped onto the 2x4 wherever you wanted them. I built myself a miter saw table with fold-up "wings" and was no longer using the rollers, but they were perfect for the Carvewright.

Harbor Freight has a roller stand on sale right now that could probably be adapted: http://www.harborfreight.com/132-lb-capacity-roller-stand-68898.html

[rbrown]

Thanks for the suggestions. My setup is kind of like DickB's except I had a bunch of castor rollers laying around so I put them in pairs on both ends I have eight on each side. Will try the suggestions and let you know... My workshop is 20 mins. away I had to take my step daughter to a college tour and I used the spare car and forgot that my shop keys were on my car key ring so I will try it tomorrow. Don't feel like driving over tonight.

[DickB]

In my experience, long boards (and sleds) are seldom 100% straight. If the rollers are not adjustable to imperfect boards, the rollers may work against you. If they curl upwards towards the ends even a fraction of an inch, the rollers will not support the end of the board when it is fully extended, and the weight may cause the board to lift off the brass roller. So then you need to raise the far rollers slightly. If they curl downwards towards the ends, the brass roller contact may be lost in the middle of the board. Then you need to lower the far rollers a bit.

[aokweld101]

DickB, I looked at the rollers and I couldn't build them that cheap thanks for the link and your reply.

[Ilonaco]

I like to use a sled with absolute straight hardwood runners and masking tape on the bottom of the side that goes over the brass. That and the two support rollers from Harbor Frieght solved this problem.

[Ilonaco]

I use a sled and hot glue 4 inches on each end so I don't waste any wood. Works fine if the rails are good.

[rbrown]

still fighting with it. I have tried just rails only and built three different lighter and lighter sleds, checked and rechecked the clearances. Even tried to making the pattern smaller to see if it would work with just the board only and that isn't working either. Tried masking tape and duck tape. Figured out it make a difference on the color of the masking or duct tape it doesn't like blue or black colors to cover the end spaces of the rails. I'm trying to put a 5/32 wide slots 3/16 deep 1 inch apart fully across and centered on a 6 foot particle board shelves bought at home depot. I bought adapters and the 5/32 cutting bit and telling the software I'm using the 3/16 inch cutting bit. Worked on a two foot test board just can't get this 6 footer to track each time. It doesn't seem to error in the same place each time it measures the board which is frustrating... Sometimes it errors on one end then the other or from the center. or where ever it "feels" like it.

[Digitalwoodshop]

Rubber Belts or Sand Paper? The Sand Paper Belts CAN roll under at the Brass Roller, especially the one at the Brass Roller and under the Cut Motor... I make it a habit of ripping off a 3/8 to 1/2 inch piece of the belt and watching the movement over time I had to rip it 2 days ago when I went to cut some more tags.

By ripping the belt: 1. The board makes better contact with the Brass Roller..... YOUR possible Rolled Under Belt may raise the board off the roller by the extra thickness of the belt. and 2. Prevents broken X Gears when the belt rolls under and jams the X Gears.

Also un plug the machine and remove the bottom and check the tightness of the 4 screws going into the bottom of the 4 smooth rails that the machine head rides up and down on.

Also set up the project as a place on end... THEN it only measures off the front end....

For ME, I do many 6 inch wide boards and I believe that is why the belt on the brass roller half gets worn and more flexible then the unused right side. It makes belt tapered like a funnel. "IN my opinion....."

AL

[rbrown]

My sand paper belts are brand new and tracking perfect and the machine only has 3 (now 4.5) hours on it. I bought it used...

I'm thinking I should have bought a real cnc for what I want to do. This measuring the board each time is a real pain.
Would be nice to set the board in, tell it where the corner is and hit go.

I finally got it to do one board but it shifted the lines or when I wasn't paying attention did the same spot twice because it skipped the last two slots.

So I put the second board in and now I'm back to the same problem.
The only difference I can see is, the second board sits about 1/16 of an inch higher in the sled on one end.
I cleaned all the sawdust out of the machine.
After trying playing with it for 3-4 hours I called it a night.
I have 20 of these boards to do....

What I had to do to get it to work is build 2 - 7 foot outfeed tables made from poly finished plywood and had them set 1/32 of an inch lower than the out feed rollers and spread super fine sawdust over both of the outfeed tables. Plus I left the adjustable inside guide 1/8 of an inch away from the sled.

It's a waste of material if I have to buy 4x8 sheets to make 6'7" foot boards to cut off 3.5 inches on each end. If the sled is the problem... I have done just plain smaller 4 foot boards that worked.

I'm going to totally check over the machine and see if there is something loose...
I just didn't want to rip into it, since there is so little hours on it.

If that don't work... I'll just to do them by hand and leave this machine to do baby stuff. I have wasted so much time and money building sleds and out feed tables, I probably could have had built a jig and had them all done by now.

[liquidguitars]

I have a boat load of sleds.... can I see a photo of the sled in question?

[liquidguitars]

I'm thinking I should have bought a real cnc for what I want to do. not a bad idea but...

I helped my Son not log ago to make a sign for a movie project for his production co in LA, The letters where cut out of a 8' x 10" x .25" and 4'x 10" board taped to a second board the same size but .75"
no issues I did not even have backup rollers. The CW worked really well, even ran a pass 45 chamfer on letters. the sign finished a 12'

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[Digitalwoodshop]

Question? Which direction are the Groves? Do they go in Width or Length? If Width, do they go from edge to edge? IF so, then the rubber roller is falling into a grove causing less pressure on the board on the pressure roller. A Picture of the problem cut and posting the mpc would be worth a 1000 words... Since you stated that one board worked until the end and if I understand correct, the board failed to position in X or length due to the board loosing contact with the brass roller....

We are back to basics.... I understand your frustration....

Things to check off and report back when you tear into the machine.

1. The 4 screws on the under side of the machine that go into the 4 smooth posts... Are they tight...?

2. With a board in the machine and a bit in the chuck. Move the Z Head to the top mechanical pin stop. On the keyboard, Options, Sensor Data, Z Data. This will display the Z data as 0000 where ever the head is when you turned on Z Data. The Z Motor has a encoder that makes pulses. Move the head to the left edge of the board and touch the bit to the board. Note the reading. Move the head to the other end and touch the board. Note the reading. This will show if your head is level. IF the Brass Roller SIDE of the head was HIGH, that could cause this problem.

3. Remove the Right Side or non keyboard side and then the dust cover on the X Gear Box. Clean any sawdust and inspect the gear teeth. LOOK for a missing tooth.

4. Take a marker and mark the Right Side Metal Roller that the Sand Paper Belt rides on in the middle of the machine. Marking the current position. This will aid you in seeing a Rolled under belt later... A Reference Mark on the Roller near the gear box.

5. The Brass Roller has a little piece of RUBBER under the Assembly that pushes UP the Brass Roller.... MANY times users have reported that the little piece of rubber has been SUCKED into the Vacuum and long gone.... I suspect it is gone..... And causing the problem....

6. Try a project using place on END. Are you using Center on Board?

And a picture of the failed project too...

MANY WAG's here..... Wild AL Guesses..... So many questions...

AL

[rbrown]

Before I run over to the shop, I was doing some poking around on the forums and saw where on the Brass Roller says it is supposed to have an O ring on it. I don't remember ever seeing one on my machine. I have an A version Craftsman Machine Is that supposed to have one? And if so, what size is so I can grab one before I get there, just in case. My shop is out in the boonies...

Will answer the other questions and take pics for sled and first board after I get back from the shop later on tonight.

Also thinking about the skipping the last two slots... After the last version of the sled, I forgot to change the board size, I made the headers from 2x6 inch pine dimensioned and mitered to fit over 3/4x3 Red Oak rails and it sits above the rails 5/8 of an inch with 5/8 wide pine side rails. So the board length will be off. Can't remember how much I left of the 2x6 under where the board sits. But I know it is longer then originally planned.

[bergerud]

I think it is 5/16 inside and 7/16 outside for the A ans B type machines. The C machines have a smaller O ring.

[rbrown]

There is the problem... I remembered looking at the brass roller before and turning it by hand and it turned like it had resistance and since it was like that when I got it, I assumed this was the "normal" operation. Apparently doing smaller projects didn't affect it. So when I went over there last night and looked closer at it, the O ring was pushed off the roller and was rubbing between the roller and the board guide. I got it back on the roller and now it spins like a top.

Didn't get a chance to run it because I need to change the board setting for the new sled that was the second problem. I made the headers larger with out thinking about having to change the board size. While messing with the rollers, I forgot to plugin my laptop or it got unplugged and it hibernated with designer open and for some reason it crashed my hard drive. So I been fighting with it trying to get the hard drive to work and ended up having to reinstall the OS and found out that Microsoft has stopped providing updates for XP (I have XP Pro) So I have had to download the files manually from HP and MS to a USB drive then and install them. It is a real PITA...

So will let you know later on how it is working. I'm pretty confident that those are the two problems.

[rbrown]

After fixing the o ring still not measuring right. And while I was doing another measurement, it started bucking back and forth and broke a drive gear tooth before I could get to it and stop the machine.

So I bought a new drive gear set and a spare and figured I would get the rubber belts too.

So after installing the belts and the drive gear and recalibrating the machine, I have a weird problem...
Also I could only get the calibration down to 36.036 And when I tried entering for example 884.100 it would jump a few digits higher or lower .096 or .116 depending on the number entered no matter how many times I entered it in. Is that normal?

So anyway...
Now I have this problem...
If I use the length measurement function the board measures 81.125 which is correct.

But when I run my program it says the board is 75.053.

And If I go back to measurement I get 81.125 or very close to it.

Any ideas why?
Thx,
Bob

[CNC Carver]

After fixing the o ring still not measuring right. And while I was doing another measurement, it started bucking back and forth and broke a drive gear tooth before I could get to it and stop the machine.

So I bought a new drive gear set and a spare and figured I would get the rubber belts too.

So after installing the belts and the drive gear and recalibrating the machine, I have a weird problem...
Also I could only get the calibration down to 36.036 And when I tried entering for example 884.100 it would jump a few digits higher or lower .096 or .116 depending on the number entered no matter how many times I entered it in. Is that normal?

So anyway...
Now I have this problem...
If I use the length measurement function the board measures 81.125 which is correct.

But when I run my program it says the board is 75.053.

And If I go back to measurement I get 81.125 or very close to it.

Any ideas why?
Thx,
Bob

Did you pick stay under roller. If so the measurement will be shorter by the amount to stay under the rollers.

[rbrown]

in that case shouldn't it be 74 inches? 81-7

[CNC Carver]

Should be but try to load without staying under the rollers and see what measurement it comes up with.

[rbrown]

k I'll try that when I get there my shop is 30 mins away. Had a problem with my laptop so I'm home fixing it.

[rbrown]

sorry for the delay...
Had to get a new hard drive and reload the software on my shop laptop...
I selected no for stay under rollers and it carved it. So it is working.
Will say one thing it does measure and line up pretty accurate...
Way I could tell is I'm doing 5/32 inch slots 3/16 inch deep 1 inch apart.
I broke one bit half way through a board replaced the bit and restarted the program with the same board and it was dead nuts on.
Then I had one slip off the rails on one end so it routed one side and feathered the other to nothing. This was at the last foot of the board.
So I set the board back in the rails and restarted it and it routed the slots exactly the same.
I was amazed both times.

However... I think they should have a sensor so if the cut motor starts bogging down it slows the cut rate.
After doing a few boards the bit started getting dull, over heated and that is why it snapped.

Only thing I don't like is...
Why does it start out measuring: (facing the keyboard)
to the left side of the board
then to the right side of the board
then to the left side of the board
then asks if I want it centered
then goes to the right side of the board and then asks to load the bit then starts routing.

Doing 6' ft. boards it takes forever and seems like a wasted extra trip the length of the board.
Should reverse the process, then it would be at the end it is going to start cutting at.

[Digitalwoodshop]

Place on Center measures TWICE.... IF you learn to design projects to use "Place on End or Corner" it will only measure once....

Tips and Tricks for more details.

AL

[RMarkey]

"Place on End or Corner" it will only measure once.

Not necessarily. If the board is short and comes off the rollers, it will measure front-to-back-to-front.

Technically, its not measuring twice... its re-indexing the front because it came off the tracking roller on the back.

[Digitalwoodshop]

Good Point... I had forgot that. I normally design my projects with 4 inches on the right side of Designer and a longer than required board and cutting the project off after done.

AL