...I think you figured it out, but the slower (lighter) the passes you get better results.
As you push to hard, the blade deflects up and gives you those minor errors.
As a finish - put that sanding disk on the grinder with 36/80 grit on that grinder and surface grind that rail section dead flat. Then you have a really flat top referenced surface to grind your profile on.

I have now made 3 sets of rails from scratch!

Sean

Cool, thanks Sean. I was doing the lighter passes, but when I got to about 2 mm left on the rail, I went for one heavy pass as the wheel gets stuck when it gets too deep. Is that what I'm supposed to do? I'm going to sand them out today flat on top.

Chris

The jamming is from the cut closing up a little, probably from the heat.
So stop and relieve the cut by bending the remaining top back slightly to open it back up again.
Use some vise grips and run along the top of the cut bending it back every 200mm or so.

Ross

...Ditto what Ross said.

Thanks guys, yes I figured out the vice grip trick. It seems that the best time to cut through all the way is when the other side of the rail is smoking a bit. After you see smoke, then the next pass should cut right through fairly easily. It takes a lot less disc too if you just keep cutting until it slices off. I did one 2.5m rail yesterday with half a disc so that worked out well. It seems the sanding though gave the top a bit of a slight convex shape. Not sure why that happened, perhaps the backing disc was not as hard as I had hoped for. Will try with a different backing disc today.

Thanks for all the help, it's really working well now. .1mm variance last night across 2.5m so looking quite nice.
Chris

Use a regular grinding disk (new) as the backer. This is a very rigid precise backing plate.
Or, one of your thin cut of disks. Light pressure until you see even sparks.

Well I finished all my cutting and sanding, they turned out good but I have a slight problem. One X rail is 28.9 mm and the other is 28.1mm give or take .2mm tolerance. Should I grind down the 28.9 mm one to match? I recall doing something like this before but ended up messing up the evenness of the rail by trying to take off too much material. I learned that one should do all the cutting with the jig at same settings, then all the sanding, then all the profiling. Don't cut, then sand the same rail, and move on to a new one to cut or you'll end up with uneven rails from one to the other.

Anyhoo, a whole manual could be written about grinding rails! Tomorrow I will profile them.

I ended up welding two pieces of smaller rail together for one of the Y rails so I wouldn't have to order yet another one. Here is how I did it. (Excuse the welds)):D

1. First I put the two manufactured ends together, which made them relatively fit easily together, straight.
2. Clamped the two halts flush to the edge of the main X beam with a melamine board underneath.
3. Then clamped a piece of 50mm x 6mm flatbar on the backside of the rail.
4. Took a piece of yellow nylon line and stretched from end to end to make sure everything was straight (it was)
5. Tack Welded, then welded them together, rechecked the line.
6. Grinded out the welds and flap disced them flat.

Thanks for the help Ross and Sean, and everyone. They are very precise now over the length of rail.

Cheers
Chris
http://s14.postimg.org/pm4atk0f5/IMG_2084.jpg
upload foto
http://s14.postimg.org/pne8mz28x/IMG_2085.jpg
windows 7 screen shot
http://s14.postimg.org/5u24u9ov5/IMG_2086.jpg
upload foto
http://s14.postimg.org/wt5zpfbc1/IMG_2087.jpg
upload foto
http://s14.postimg.org/816di6u5d/IMG_2093.jpg
upload foto
http://s14.postimg.org/5l4k4cc2p/IMG_2097.jpg
windows 7 screen shot

1mm difference in rail height from one side to the other is no problem. At the end of the day you trim/face the table surface so that everything comes to "zero".

Thanks Gerald, That's good news that I don't have to grind the tall rail down further. Do I shim up the opposite rail to match in the end when shimming them?

Why bother to raise the rail if you don't even know your main beams are the same height, taper or whatever? Believe me, when you start shimming, you will be grateful for having one less factor to measure.

Probably will work out for the best during shimming, because, ill bet one beam is out by 1mm anyway.

Yesterday, I finished cutting and sanding all the rails then profiled 2 rails, (a test rail and one of my X rails) before it got too dark outside to work quietly. The skate worked really well, was impressed at the quality of the final profile and how easy it was to fine tune. Really slid well with some cutting oil across the rail. It was a bit difficult getting started as the skate was sticking due to the bend not being sharp enough so I adjusted the eccentrics and lubed it up. I suppose I needed to specify K factor or bending radius for that piece to get it perfect. One set of bearings kind of sticks out a bit to the side but it works well still. I would caution being very careful your hand doesn't hit the grinder as it is entirely possible to happen (it took a chunk out of my finger)

The thing that made a difference for me was using a grinding disc, cutoff disc (pferd 1mm), and a sanding disc sandwiched together. The 1mm cutoff discs between the grinding disc and sanding pad smoothed out the dip in the grinding disc and made the whole sanding surface flat and hard. It also helped when the apparatus became too low and the heads of the bearing post screws hit the wells of the rail flange to add yet another cutoff disc to the sandwich. This spaces the sanding disc 1mm further down for a nice final sanding. I used 36grit to start, then switched to 60 grit when the profile top was 2mm, then went over a pass with 100 grit once I had to added the cutoff disc to the sandwich. Then went over the whole thing lightly by hand (block) just to polish with a 400 grit. I'll post some photos of the finished product later on but here are some of the test.

http://s21.postimg.org/woaq237uv/IMG_2111.jpg

http://s21.postimg.org/p9le9plzb/IMG_2113.jpg

http://s4.postimg.org/70hrdjust/IMG_2102.jpg

http://s4.postimg.org/j137ea27h/IMG_2109.jpg

I wore welding gloves while working with the skate, and I did take some leather off one of the gloves; it's easy to have a hand slip. Your test rail looks great!

...that looks incredibly familiar! Well done.

Thanks! I've finished cutting and profiling the rails. They turned out excellent, thanks to a lot of help from people here. Just need to redrill a few holes in some of the new rail, then I will be mounting them and testing the roll soon.

Next week will be ordering control box stuff, will take a while to get, but should be quick to put together.

I don't have any rack and pinion yet, will need to order overseas for that. Not sure where would be best, probably china.

ok, will post progress tomorrow or sat.

Over and out!
Chris
http://s15.postimg.org/rs8nun957/IMG_2115.jpg

well done!

have ordered my rack and pinions from www.mooregear.com
It was the only company i found able to shipping it to me.

Rolling smoothly!
 

On Friday I leveled the table, and used the 2m all thread clamps I made to tune the X beams a bit more which really worked well. I had cut into one leg and shimmed the X beam on that leg with washers, then welded it back shut. The beam was level then on the Y axis. I essentially squeezed them into place then ratcheted down my 75 PFC crossbeams till very tight. When I loosened up the clamps the machine was completely level in the X direction and by looking at the level on the gantry, it looks as if they are level in the Y direction as well but I will fine tune that with my laser as soon as I figure out how to do that.

I then mounted the X rails and measured 15mm from the edge of the X beam to the edge of the rail before clamping them down. Then went through with my square to make sure the 15mm gap for the rack was consistent all around, which it was; however, There is a slight bow in the beams so it's not completely square from flange to webbing, but there is enough space for the rack nonetheless. I'm thinking it must have happened when I tried heating them to straighten them. An engineer friend I have said to never touch heat to the webbing part of C channel as it will warp. Well it must have warped, or must not have been square to begin with. Wouldn't doubt it either way. :rolleyes:

After I clamped the freshly ground rails, I couldn't resist, had to mount the gantry and test-roll it. I couldn't believe it, it rolled SO smoothly and on all 4 wheels not a single adjustment had to be made. The spacing from Xrail to Xrail was spot on the money, which was a huge relief to say the least. :)

Next were the Y rails, which I'm not sure what has happened but they were too far apart. The gap is further than 15mm on each rail to the Ybeam so the car wouldn't roll right. I had to take off the M12 thin nut on one side and use washers instead which must be ground around the edge or something because the washers are causing the bearings to lockup. So will see if I can get smaller washers, or just drill through some M10 washers to M12 size. With a bit of loosening of the nuts on the Y car, it started to glide nicely, and on all fours. So my machine's tolerances look to be in the green, what a relief. No major adjustments!

Having my stop blocks cut, and needing to get the turned parts turned soon. I'm going to order the three C's tomorrow, Cable, Contactor, and Control box, along with door interlock, and so forth. Was thinking of using this contractor any thoughts? Contactor LINK I was looking at 24v contractors, but seems just as expensive to do that with a 24v PS.

Here are some photos of my progress. I have a black and decker self leveling laser, along with a Bosch laser distance measure so I'm hoping that between those two items, it'l make the shimming a lot easier. Someone mentioned using Coke cans for shimming material, so I'll probably be getting some coke soon, or redbull if that will work :D

Have a good weekend!
http://s16.postimg.org/9tue672np/MG_7081.jpg

http://s16.postimg.org/v4ryagks5/MG_7079.jpg

http://s16.postimg.org/5ai5koks5/MG_7073.jpg

http://s7.postimg.org/78m0t7e3f/IMG_2122.jpg

http://s8.postimg.org/72i7a7gpx/IMG_2126.jpg

http://s05.flagcounter.com/count/5qi...ews_1/flags_1/

Are you gonna shim the rails?

Hey Ken, I sure am, but need to make a laser car first out of some angle iron.

I think the y-car is the wrong way around? (cable carrier connection should be on the other side of the table?)

I need to flip the gantry around, forgot to do that the other day but thanks for reminding me.

Hi guys,

Well this may be a silly question, but can't find it anywhere and could use some advice. Is it ok to use a 4 pole contactor on a single phase machine? In other words can I use just 2 poles of it? I will update it to 3 phase once I get into a building with 3 phase and spindle so will want upgradeability.

Also, if I am using the OM PK296b2b7.2 motors, Gecko drive G203v, can I get away with 12amps on the contractor rating?

Many thanks,
Chris

Surely， you can use just 2 poles of a 4 pole contactor.

Even if all 4 motors are drawing 6 amps at 60V, it will only draw 12A from the wall 110V single phase wall plug. 6A from a 230V single phase wall plug.
BUT you gotta factor in other thing that you may draw power from the same plug, such as the fans, disco light, etc etc...

Nice looking machine,
Cheers,
Tim

Thanks,

Hey Ken, I was wondering, if I do go with a 4 pole, does that mean that the 4 pole can only handle pulling 3amp per pole? or up to 12 amp per pole?

Hi Chris,
I don't understand your question. but I would suggest you study the specs of the contactor; Almost all contactors which I used has their rating printed or cast on the housing. Look for current rating of EACH contact. If 1 contact can not handle the current, use 2 in parallel it 2 is not sufficient, use 3 ... etc etc ;) . not the smartest & the safest thing to do but if u really can't part with the extra US$20.... ;)

A multipole device has its rating per pole. Therefore 12A per pole.

That's good news. Thanks guys.

I've read a lot of the posts about Chinese spindles and am impressed. Looking at the current landscape of Chai spindles, thinking about ordering a Chinese spindle, but not sure which type to go with, the 4kw air cooled or water cooled. There are so many Chinese sellers too, are they all good? Anyone in particular who stands out as an exceptional Chinese spindle dealer? I've seen plenty of spindles all looking the same, but priced widely different to each other. Some with 4 bearings, some with Japanese bearings, or German bearings subbed out.

Also, I am thinking of purchasing either a Hitachi 5hp VFD or X200 3hp. I read somewhere on here that a 3 phase VFD can be run single phase, is that true? Is there a huge difference between 3hp spindle and 5hp in terms of ability to run 24/7?

Thanks for any info.

Chris

Hi Chris, I run a Chinese 3hp spindle on a 1 to 3 phase VFD. Works great. Super quiet compared to the 3hp router. I have run the spindle on one phase but that wasn't a good sound. I run my setup on average 6 hours a day. A few times run for 36 hours with no problems. Then there's the amount of bearings, 2 for wood more for metal. Pick something that's easy and works, the cash will follow for the 5 hp upgrade.

Cheers
Tim

Bigger is always better. Other factors to look into are 1) cost (obvious) 2)can your house electrical system take the load. Don't want to see you burning down the house just because your house wire spit fire due to excessive overloading.

Thanks for the help guys. I really would like to get a 5hp water cooled 4 bearing spindle if possible but don't want to burn the house down or anything like that :D. Not sure how the house will handle it but planning to move into a commercial space. I'm on a 230v 50hz grid at the house. Will check the breakers out.

My main questions are, are most of the Chinese ebay guys fairly reliable and with regards to the VFD, should I go with a particular one? I've tried searching for a few of the ones mentioned on the site but they are no longer there. Someone said that it's better to go with the Hitachi inverters over the Chinese ones. I was reading here that the 3 phase inverters can run on 1 phase, is that true with the Hitatchi 3 phase 5hp VFD too?

Thanks,
Chris

Hmm. Let me be a little contrarian here.

What advantage do you expect to get from a 5hp spindle vs a 3hp spindle? Are you planning to work with exceptionally large cutters?

Don't get me wrong - there are times when bigger is better, and overbuilt can be an advantage. However, depending on what you are trying to achieve, you may spend more than you need to make a machine that requires an atypically large and expensive power source, and doesn't perform any better on the primary task.

A MechMate with a 1 HP router is clearly not operating to it's full potential. Moving to a larger router, or up to a small spindle gives an obvious improvement. Moving to a 15 HP spindle would pretty clearly outstrip the capabilities of other sections of the MechMate. Whether the point of diminishing returns sets in at 4HP, 5HP, 7.5HP, 10HP is probably worth a few moments of consideration.

I am a big fan of the Hitachi inverters. Be aware that when operating on single phase input, you may have to upsize the inverter (use a 7.5 HP inverter for a 5 HP motor). Your supplier can help you sort this out. Usually the smaller inverters (3 HP and below) have single phase versions without upsizing.

3Kw or 4hp is about the safe operating capacity of a single phase 230V 50hz supply on a 13A fuse. That is what I am running. & its not diminishing return. I run 50mm ball nose most of the time, & 2.2kW just won't do it, will trip when the tool bit is less than razor sharp. Also, you know that bigger spindles maintain a more constant RPM with varying cutting load.
Chinese or Hitachi inverters... I can't comment, I'm too poor to buy a Hitachi. Also, I'm too lazy to utilize all the Hitachi feature, enjoy operating the VFD manually, keeps me busy. :)

I agree that moving from 3hp to 4hp, staying within the bounds of a typical supply circuit makes sense. I am questioning whether moving beyond that makes sense, when the costs of the spindle, wiring, VFD (especially if upsized for single phase), and special circuit in the building start to add up quickly.

To be specific, I have run the Huan Yang inverter, and the Hitachi X200 series side by side in the same environment. The HY was essentially an all-frequencies radio jammer; it blocked cell phone and wifi in the room, created audible noise on a cd player, made tuning in a radio impossible, and caused the proximity sensors to be unreliable. The Hitachi does none of the above. Maybe I got a bad HY, but I'm sticking with the Hitachi. :)

Hi Guys,

Thanks for the source of info on the spindle. I really appreciate the discussion here. I may be moving into a commercial building with 3ph fairly soon, so that would make things ok with the electricity. I just have one question, is a 3kw able to cut sheet metal and acrylic at a reasonable rate of speed? Steel and Aluminum? I'm needing to cut aluminum sheet and acrylic. None of it is that thick, but I also want to be able to cut fairly quickly as sometimes the deadlines are a bit unrealistic. An X200 is reasonable on ebay used at the moment. Moving up to a 5hp Hitatchi though it about $680.

Anyhoo, thanks for all the info guys.
Chris

Spider Plate holes
 

Regarding the spider plate. Mine has no markings... So I've been trying to find datums to measure off of and looking at the spider plate plan, it looks as if one side is further over than the other by about 2mm. Is this deliberate? Just wanted to make sure before I start drilling holes.

Here is my drawing of my spider plate where you'll notice that the hole pattern is not centered.

http://s16.postimg.org/cj91cbd5x/Spi...et1_page_1.jpg

The laser cuts and marks are symmetrical, but a 2mm variance in bending is normal.

If the spider fits in the carriage, that's the main thing. Spacers/washers are used to fill the clearance. You can pack those on any side you want.

Thanks Gerald. I drilled it and it looks good.

Now I've stumbled across a fantastic price on LAPP Olflex cable with a BLUE outer sheath. But there are some things I need to get input on before going ahead with it. First off it's .75sqmm but I'm only running half coil PK296 B2B sg7.2 which is ~38vish 3.5amp. The LAPP .75mm is rated at <75VDC. Ay thoughts here? Here is a spec on the cable. It's saying that the static is 7.5x bend radius and up to 20x bend radius.


Ölflex EB CY Blue Intrinsically Safe Control Cable (screened)
Olflex® EB CY is a PVC control cable with a blue outer sheath for use in explosive atmospheres with hazard type "i" (intrinsically safe). Complies with DIN EN 60079-14 section 12.2.2 (VDE 0165 Part 1). The copper braid screen is for protection against electrical interference.
Designed in accordance with HD 21.13 that is VDE 0281-13
Conductor: fine wire strand of bare copper to IEC 60228 (VDE 0295) class 5
Core insulation: PVC compound TI2 in accordance with VDE 0281 part 1 (HD 21.1 S3)
Identification: in accordance with HD 186 that is VDE 0293; black cores with white numbers, without green/yellow ground conductor
Wrapping: Insulating plastic
Screen braid of tinned copper, coverage = 85% (nominal value)
Outer sheath: Blue PVC compound TM2 in accordance with HD 21.1 S3 that is VDE 0281 part 1
Electrical properties at 20°C: Nominal voltage <50Vac; <75Vdc
Rated voltage: <50Vac; <75Vdc
Temperature range: -5°C → +70°C (flexible installation); -40°C → +70°C (static installation)
Minimum bending radius: 20 x cable diameter (flexing)
Flame retardant in accordance with IEC 60 332.1
Tested in accordance with VDE 0472 and IEC 60 811-X.X that is VDE 0473
Note
The product is for use in the voltage range:<50Vac and <75Vdc and is therefore not in accordance with the ECD 73/23/EEC (Low Voltage Directive). Compatible connecting glands must be used and correctly installed to meet ATEX requirements.

The spider and Z slide is nearly complete with exception of the gas spring and bracket. I ground down a profile on the plate and it turned out quite well. Then cut the plate and blued it for precision layout. Punched start holes then drilled 3.5mm holes in the plate. Enlarged them to 6.5mm. Countersunk them using my new Bordo Cobalt 20.5mm Countersink. It cut beautifully and quickly but made some ultra fine and sharp swarf that kept lodging itself in my fingers:mad:. My press lost a bit of it's clamp as the holes went on so they progressively got slightly bigger. Lucky it was just a test flatbar until the ground plate comes.
http://s8.postimg.org/t2ohk2u2p/IMG_2139.jpg http://s8.postimg.org/8smkr73k1/IMG_2140.jpg

Transferred the hole pattern to the RHS 50x25x3, tapped to M6, and locked it down with the countersunk allen caps. All went well there, perfect alignment.
http://s8.postimg.org/4q055uytd/IMG_2141.jpg http://s8.postimg.org/b2fafp1vl/IMG_2143.jpg

Welded the spider plate and instead of having the bearing posts turned I found some collars that exactly matched the posts and they worked well.

My spider didn't have marks so I spent a few hours trying to get a perfect alignment and distance on the spider with my calipers and square. Scribed two lines and used my calipers to get the cross scribes prior to punching them. Measured and it was perfect. Then I tapped the holes in the spider and put the whole thing together. Smooth rolling and all rollers making contact evenly. It's a nice feeling when everything glides smoothly in the end. :D
http://s8.postimg.org/lsybnmq4h/IMG_2147.jpg
Here are some pics of the finished Z slide minus the Spirng and bracket. Also, I haven't welded the nuts on the back yet, but I will do.

Ordered most of my electronics, purchased two contactors, and a 4 pole breaker. Got a great deal on a 40amp 4 pole contractor from Italy for $25 NZD. One from China for a tad more. Next going to get a spindle.
http://s8.postimg.org/n9efjiif5/IMG_2163.jpg
Cheers,
Chris
http://s8.postimg.org/euu7hos05/IMG_2152.jpg
upload
http://s04.flagcounter.com/count/TBm...ews_1/flags_1/