Frage Just purchased and have a few questions

While I did watch nearly every video I can find on the SC machines. I didn't discover this forum until after I purchased. My unit hasn't shipped yet and as I read through the assembly and maintenance posts it seems like many people have quite a bit of problems. This is a major purchase for me and I'm nervous. My biggest fear is that I get the machine and can't figure out how to put it together. Or I screw it up in the process. I've seen people posting that it took them a week or more to get it put together only to not have it work. So my questions.

1. How long did it take you to put it together?

2. If you could do it again would you shell out the cost of having them assemble the unit?

3. They say 3-6 hours for assembly is that realistic? If it is, it seems they are charging an awful lot to put it together. It seems they want people to put it together themselves as this likely removes some liability for them being responsible for it working. On the other hand putting it together will give me insight into how it works. But I'd kind of rather figure that out when there is a problem.

4. My primary intention for the machine is to mill cutouts into plastic electronics enclosures. The material is ABS about 3mm thick. Will the dremel 4000 get the job done for this?

This forum seems like a great resource. Glad I stumbled upon it!

Hi Xinort,

With the greatest respect to Thomas, I think that for someone new to the machine even 8 hours is unrealistically short. It took me the best part of a day to identify, sort and label all the small parts into individual plastic bags - this is a really worthwhile exercise and will save hours of searching as assembly proceeds!!

Being a bit of a perfectionist, it took me several days to get my machine assembled and adjusted to my satisfaction!!!

I would recommend you do a more or less full mechanical assembly before wiring the machine - it's so much easier to get the tuning/adjustment correct without the encumbrance of the wiring hindering everything you do.

You will find the Y-axis in particular needs very careful "tuning" to get free movement over the full extent of the axis. On my machine I had to relieve the Y-axis leadscrew remote end bearing seats to avoid binding of the precision nuts.

Make sure the two gantry side arms are both set to the same angle - I temporarily fitted mine to the same side guide with the two vertical faces of the side arms together, parallel and at 90 degree to the guide rails - careful positioning of the fixed rollers will let you achieve this. Don't rush this step as it ensures the spindle will be close to correctly trammed.

Be very careful not to over tighten the adjustable rollers during final assembly - it is too easy to jam the Y-axis particularly, I tightened mine until free movement was just eliminated. In my view the recommendations in the Stepcraft manual puts too much load on the guide rails and could lead to mechanical damage at contact points.

Another point worth checking is that the "homing" micro-switches operate before mechanical limits are reached!! The Y-axis switch is recessed, and if I remember correctly I had to slot the mounting bracket holes to make sure the switch operated before the gantry hit the screw.

On the software side, UCCNC is an excellent choice and, coupled with the UC100, frees the controlling PC/laptop from all critical timing issues.

Just my personal views - no connection to any H/W or S/W vendors.

Good luck - and don't rush things, patience will pay dividends in the end.

Peter

Thank you for your replies!

ThomasDbg schrieb: I cannot believe, that someone of Stepcraft said 3-6 hours

I'm in the us and bought from stepcraft.us On the product pages it says :

STEPCRAFT systems are shipped as a kit. You can expect the average assembly time to be from 3-6 hours. No special skills or tools are required. There is no cutting, drilling or tapping required – simply bolt all the components together

I'm very interested in hearing others experiences and tips.

Agree with Peter.

slow and steady wins the race.

Thank you all for your replies! So I'm going to go for it and build the machine myself. Sounds like I'm in for 8+ hours. I'll keep track of the time it takes and report back once it's built.

Hi Xinort,

I recently purchased a machine, without any significant experience in the field, and it took me a few late evenings after work to finish the assembly. The value of assembling yourself is that you understand the limitations of the system better and it also means that you know what can be adjusted in order to improve performance. I found the supplied manual to be excellent and in combination with the videos it really made things a lot easier.

In my system I needed to shim the y-axis aluminum profiles in between the front and back plate of the system to avoid that tightening the screws would push on the lead screws. For this it would have been great if Stepcraft would have provided a few pieces of shim discs to use. Other than that the alignment was pretty straight forward. I've borrowed a linear gauge from work to characterize backlash and spindle holder stability and found that I can't reach 80 µm backlash for the x/y-axis. Instead I find that the backlash is around 125 µm. The stability of the spindle holder when pushing/pulling is of the same magnitude. Using the technique described in the manual the orthogonality between x- and y-axis of my system ended up around 0.1 degree, which leaves some room for further improvement by either milling test rectangles or using a linear gauge against an aligned test square.

I decided to go with the UC400ETH instead of the UC100 to make sure that my computer is opto-isolated from the stepper driver. It works really well and the second port of the UC400ETH will come in handy when you realize that you will want to control your exhaust system (vacuum machine in my case) as well as the pump for the HF spindle. I've used Fusion to design a housing for the UC400ETH since it comes bare PCB from cncdrive.com.

Cheers, Per

Another +1 for peterg1000's comments.

I reckon I've spent 6-7 hours getting the track rollers on the XZ module tuned alone!

"You will find the Y-axis in particular needs very careful "tuning" to get free movement over the full extent of the axis. On my machine I had to relieve the Y-axis leadscrew remote end bearing seats to avoid binding of the precision nuts.

Make sure the two gantry side arms are both set to the same angle - I temporarily fitted mine to the same side guide with the two vertical faces of the side arms together, parallel and at 90 degree to the guide rails - careful positioning of the fixed rollers will let you achieve this. Don't rush this step as it ensures the spindle will be close to correctly trammed."

These are great tips which I'll try when I come to assembly the gantry and slot into the Y axis extrusions.

I recently made the effort to tram my unit by shimming the base for the spindle holder relative to the z-axis. I found 0.5 and 1.0 degrees of tip / tilt correction needed.

I'm curious to hear what peterg1000 was able to achieve using the method he described below:

Make sure the two gantry side arms are both set to the same angle - I temporarily fitted mine to the same side guide with the two vertical faces of the side arms together, parallel and at 90 degree to the guide rails - careful positioning of the fixed rollers will let you achieve this. Don't rush this step as it ensures the spindle will be close to correctly trammed."


Cheers, Per

Hi Per,

That's about as close as I managed, though I haven't measured mine directly!!

I've been making some gears for a wooden clock recently, and it is quite obvious that the tramming I achieved with my crude method was not good enough to prevent a noticeable wobble (1 - 2mm at the periphery of an 8" (sorry - 20cm!!) gear.

I've been giving some thought to a way of correcting this without having to shim the bottom plate, and I think that using two tapered seating shims for the spindle might be the answer. Rotating these relative to one another would vary the angle between 0 and a maximum of, say, 2 degrees, and rotating as a pair would allow the offset axis to be rotated independently.

As a thought experiment it works a treat - but there might well be practical snags which I haven't reckoned with!!

The shims could be milled tapered from a single sheet of brass or aluminium, and then the shim outline milled to fit the spindle mounting flange with a reference indicator at maximum or minimum thickness. This is one of the projects I want to tackle before I go further with my clock wheels, and could all be done on the Stepcraft.

If it works then perhaps Stepcraft should add these to their range of accessories.

Peter

Hi peterg1000,

I may have misunderstood what you meant in your post and if that is the case you can just disregard my comments below.

However, to me it sounds like the problem you're describing with your wooden gears is that your bed is not level with the x/y-plane. Try leveling the spoil board by using a flat end mill and a clearing strategy to make sure it is flat.

If your spindle is not trammed to the x/y-plane, the effect would be that such clearing strategy will leave groves on the surface and that deep pocket milling may cause the edges of the pocket to touch the mill further up on the shaft.

Does this make sense to you?

Cheers, Per

Hi Per,

Thanks for your comments - perfectly sensible.

I had checked the MDF spoil board before I started the clock, and amazingly it was flat to within .002" over the whole area - and I hadn't milled it flat either (I do have an aluminium T-slot machine table fitted)!!

The spindle I checked with an engineers square against a straight 3" length of silver steel in a 1/4" collet. This ran absolutely true when the spindle was rotated, so I am pretty sure the checks I made are realistic.

The centers of the clock wheels were reamed on the router at the same time as rest of the milling was carried out. I used a 1/8" end mill for the final cut, and the holes are a nice tight fit on an 1/8" silver steel shaft. This being the case the deviations in the wheel center correspond well with the direct measurements on the spindle.

I'm going to try machining a couple of shims to see if my crazy idea works!!

Peter.

I now understand what kind of wobble you were referring to. Tramming the spindle should improve it!

Cheers, Per

To be fair the assembly time should not be an issue.
If you are to identify every part of the machine in the process of assembling the machine then of course that will add lots of time to your build.
The most important thing is to follow the instructions and adhere to them as closely as possible to eliminate any errors which in due course will lead to a successful build ensuring the machine will work satifactorily.
It is not a race, and your own diy/ engineering skills will determine how long it will take.

I was troulble free with my 420 build. I did have one problem to not tighten securely the motor coupling grub screws on x axis.
Later after about 2 years (purchasedaugust2014 ) I had to replace the X axis.
Primerily machining wood but some aluminium too.
If anyone has the need to replace the x axis i took plenty of photos to show how, let me know and i will upload a post describing how.

I was troulble free with my 420 build. I did have one problem to not tighten securely the motor coupling grub screws on x axis.
Later after about 2 years (purchasedaugust2014 ) I had to replace the X axis.

Here we go again... crappy design all over.

You have a long way to go and a lot of screws to tight and un tight.

Xinort - Let us know if you made it. I'm still struggling with my machine since April 16.