Dust Shoe Attempt

[FWMiller]

I've been wanting to try to build the dust shoe project posted by Bergerud for a while now and finally got to it. I thought I was doing pretty good on the first part. The front and back were nicely aligned. The Carve was in the home stretch when the machine went a bit kooky and snapped off my 1/8 cutting bit. The bit is new so it is (was) still sharp. It only had about 45 minutes on a poplar project plus cutting out the sleds for the dust shoe. Any ideas on what went wrong? Not a big deal ruining a couple pieces of acrylic but 90 minutes on a $40 bit is pretty painful:-(. I'm hesitant to try again unless I can find some cheaper 1/8 cutting bits to put in my ER11 chuck which is sitting and waiting to be tried out for the first time.

Frederick



67294

[bergerud]

Did you see what happened? Did the bit slip out of the chuck? I do not think the project is responsible. It is some easy cutting. Go and buy an upcut, two flute, router bit like the one in the picture. It will cost about $20 but you need not fear it breaking.

[FWMiller]

Unfortunately I did not see it happen. It's definitely not the project. It looks to me like a machine malfunction. I walked into the house to do something and heard the motor start spinning without load. I came back to find that the bit had veered off the acrylic work piece and into the sled. The bit broke when it veered back and hit the edge of the acrylic and I guess got bound. I'm not using my ER11 chuck yet so no, the bit did not come loose. I was using a carvewright bit with the carvetight pressed adaptor and it was solidly in the spindle. Something caused the path to veer off course and off the workpiece and I'm not sure where to look. I had to do my sled over a couple times because the drill holes on the left side were misplaced in the x-direction. So it looked like I had some slippage in the x-direction. When I remembered to add the tape the problem went away, so I thought that was probably the problem. The failure this time is that it drifted too far in the y-direction which took it off the work piece.

I have noticed that the x drive motor sometimes seems to labor when starting up for a board measurement. It only seems to do it when moving left. It ramps up slowly from stop but when it reverses direction and moves to the right it moves quickly and gets to full speed right away. Is this normal operation? It doesn't sound quite right. I've checked to make sure the board is not binding and slides freely against the stops. I've also got tape on the bottom of the board for the brass roller as I see often recommended. The is an A version machine. I've got less than 100 hours on it but based on previous experience and what I've read I'm unfortunately worried it's going to break every time I use it.

By the way, where did you get your 1/8 upcut router bits? I'm having a tough time finding one with the cutting length more than half an inch for a price much less than the original carvewright. Plenty of them with only 1/2 inch cut length. I also searched for end mills and had similar results.

[bergerud]

The router bit I was describing does have only 1/2" of cut and is in most router bit racks. This is good if that is all you need. It will not break. Since you have the er11 adapter, you can also use bits like :

http://www.dhgate.com/product/3-175-25-mm-double-edged-flute-spiral-cnc/168754539.html#myaccount_left-1-null

Why your y went off course like that is strange. Could just be a firmware problem formatting the card would fix. Hard to say. The funny, labor like noise that the x drive makes is a feed back problem to do with the x drive trying to agree with the brass roller data. I was told by someone at LHR that backlash in the x drive gears is the cause and it was normal. It bothers me sometimes too.

[henry1]

how you coming with Y drive flage bearing you get any

[FWMiller]

Thanks Bergerud. I'll pick up a bit locally and hopefully get a chance to run it again this weekend. I'll reformat the card just in case that's the problem and won't walk away this time until it's done. Also, I'm glad to hear the xdrive noise is normal and it's not a sign of impending doom.

[Digitalwoodshop]

I am betting the board was of proper length that it was under both rollers all the time so that rules out the board popping out from under one roller and loosing the Brass Roller... So good on that....

The Slow start up on the X on my "A" machines has been traced to a rolled under sand paper belt at the brass roller side. A very hard to see and many dissmiss this when I post it... Many times you only see the fold after ripping a section of the belt like I do all the time. I always have a metal section showing on my machine.

To do a project like this... I would have a fresh set of Y Gear Box Bearings in my machine... And have the Ripped Belt to keep the board in better contact with the brass roller.

Just my take on this....

AL

[FWMiller]

To do a project like this... I would have a fresh set of Y Gear Box Bearings in my machine... And have the Ripped Belt to keep the board in better contact with the brass roller.
AL
I did think to look at the belts and they are definitely flat and riding where they should. I can easily see the marks the brass roller is making in the tape so I think it's making good contact. On my first carve of the carrier board I forgot the tape. There was some misplacement in 2 of the corner drill holes just in the x direction so I think it was definitely slipping on the mdf surface without the tape.

What is the lifetime of the Y Gear Box Bearings? I've only got about 100 hours on the machine.

Frederick

[Digitalwoodshop]

The lifetime of the Y Bearings to failure and wearing the Y gear shaft was about 500 hours. That is why I recommend replacing them at 250 hours since you already have the machine open to replace the cut motor brushes.

When the belt rolls over the sand paper rubbing against the metal tray is the reason for the dragging of the x axis. Like I posted 9 out of 10 users dissmiss this as a problem. In my opinion, cutting the belt has no down side.... I use needle nose pliers and puncture the belt between the metal end roller and the tray then rip the belt while pushing the belt with my hands and power off.

Yes, you see brass roller marks but that is not the only issue here. Sluggish drive...

Many only find the rolled under belt after the binding snaps a tooth on the X Gearbox and when the Sand Paper trays are removed to replace the gears they notice the binding in one belt... :roll:

AL

[FWMiller]

So a new run with a fresh bit started out well but the problem with the Y-truck returned after flipping the part over and doing the bottom side carve. It had gotten bad enough that the Y truck was slipping so much that it repeatedly measured the 5 inch wide sled as 1.7". After searching the forum and reading a number of threads on the various problems I pulled of the cover to start looking around. Belts were tight and the bearings all spun plus I had recently cleaned and lubricated the rails. However after removing the Y motor and gear box I found the y truck did not move very well. So after cleaning out the bearings the truck slid nicely so I believe this was the main problem. Inspecting the gearbox I could feel a little bit of play when I push horizontally on the belt drive gear. How much play should I allow before I replace the bearing? I'd prefer not waiting until the gears are damaged. I did not want to pull apart the gearbox right now to inspect the bearing since I was not prepared to replace anything and at 100 hours they probably should not have any problems.

One other thing I noticed was after I re-assembled and tightened the y-belt I noticed a clicking coming from the pulley on the end of the y-belt where the spring is. The clicking was caused because after tightening back down the screw the pulley was not parallel with the belt. So the belt was riding out to the edge of the pulley and the teeth of the belt were rubbing on the pulley. I had to manually put pressure on the bracket so the pulley was properly aligned. Is this normal or am I doing something wrong. There doesn't seem to be anything to prevent the bracket from canting out due to the belt tension.

[bergerud]

There doesn't seem to be anything to prevent the bracket from canting out due to the belt tension.

The spring tension bolt pulls from the center of the pulley and belt so it should naturally want to pull straight. I remember the act of tightening the locking screw can skew things a little.

[henry1]

Here the sample just made of the Y gear box

[bergerud]

Looks like the line up was way off. Looks like 3/16" off in the x. What happened? Did you use a frame sled like I did?

[henry1]

Looks like the line up was way off. Looks like 3/16" off in the x. What happened? Did you use a frame sled like I did?
Yes I did use the frame sled going to try it again do you say stay under the roller when it ask ,, also just carved another one this one ok why the other one went off I will check that out

[bergerud]

This last one looks a little off in the y. Thin at the top of the screw holes.

[henry1]

This last one looks a little off in the y. Thin at the top of the screw holes.
I just use pine to carve it on the sled maybe my sled is off a bit guest all measurement have to be right on

[henry1]

[QUOTE=bergerud;220897]This last one looks a little off in the y. Thin at the top of the screw holes.[/QUOTE
When you carved it did you carve it best or optimal

[bergerud]

normal for MDF tests and optimal for acrylic a phenolic.

[henry1]

normal for MDF tests and optimal for acrylic a phenolic.
Was your bearing 625 tight in the set up mine a bit loose

[bergerud]

Mine was tight. You should have installed the ER20!

[henry1]

Mine was tight. You should have installed the ER20!
Well don;t know what to tell you , eventually I will for now will use loctite to hold it in place the acrylic might come out ok will try it tomorrow

[bergerud]

You could tweak the hole smaller on the mpc when you carve another one. Run out of the CT can make the hole bigger. Measure the hole you got with a caliper and make the hole that much smaller.

[henry1]

thank you for the info will do

[henry1]

You could tweak the hole smaller on the mpc when you carve another one. Run out of the CT can make the hole bigger. Measure the hole you got with a caliper and make the hole that much smaller.
this one I believe turn out great , now will do the acrylic one all should be good now what you think bergerud

[bergerud]

Looks good.

[henry1]

Looks good.
Now just waiting for my flange bearing,, they should be here by Monday

[FWMiller]

OK. I've tried multiple times to get the dust shoe bottom. Some failed due to operator error. Others due to machine accuracy. I had to resort to the alternate alignment method (measuring edges of workpiece, calculating y center, and then manually entering the center coordinates. The attached pictures seem to be about the best my machine can do. I can repeatedly measure the workpiece edge y-coordinates using the method recommended within .001 even after removing and re-inserting my sled. So the sensors seem to be giving repeatable data for y position of the truck. Even so, the machine still has pretty noticeable errors in the x and y, x worse than y which surprised me. The piece fits very snugly in the sled so I know when I flip it it is not moving. When I took out the y-gear box to inspect it seemed to be in good shape. I guess I'll order some new bearings and replace them to see if that helps. However that won't solve the error in x. Any suggestions on what to look for to solve the x-errors? I pretty sure the brass roller is making good contact. I have tape on the bottom and I can see the roller assembly move down when the board presses down on it. My rubber washer is missing (has been for a while) but I've read in other threads that it's not necessary to replace it. Is that accurate or should I get a new one? Checked the sandpaper belts and they look good.

I thought I might be able to get by with the shoe bottom parts inaccurate as they were and made one attempt on the pipes to see if I got lucky. Until I fix the accuracy problem it will be a lost cause trying the rest. I measured the position of the center drill pull hole and it's centered in y to within the accuracy I can measure it.

[bergerud]

Did you flip the piece without removing the sled or did you take the sled out to flip the piece? Leaving the sled in totally solves the x problem for me. As for the y problem, did you find center for each side or just the first side?

[FWMiller]

Did you flip the piece without removing the sled or did you take the sled out to flip the piece? Leaving the sled in totally solves the x problem for me. As for the y problem, did you find center for each side or just the first side?
I left the sled in place while flipping the piece. I did it during the "finding surface" routine at project start after selecting jog to position. I did not remeasure the y-coordinates for the second side, only the first. However, given how repeatable the two y board edge measurements have been even after removing the sled I'm guessing that it would account for only a fraction of the error I'm seeing. When I get back to try it again I'll try remeasuring on both sides and see what I get. I have another project where x-accuracy is an issue. I just made a separate post on that one to keep this one from getting too cluttered although I'm guessing that the root cause is affecting both projects.

Thanks,

Frederick

[bergerud]

This was two single sided carves, right? A two mpc operation?

[FWMiller]

Yes. Loaded the files one at a time following the instructions you posted in your thread.

[bergerud]

I guess the x is another problem. The y should have lined up. Dust in the y encoder? I am at a loss.

[NLAlston]

Did you see what happened? Did the bit slip out of the chuck? I do not think the project is responsible. It is some easy cutting. Go and buy an upcut, two flute, router bit like the one in the picture. It will cost about $20 but you need not fear it breaking.

I had wondered about cheaper alternatives. Good to know this.