Hello all,

I'm local to the Smithy Ann Arbor facility, and was planning on taking a visit to their showroom. I called them a couple of weeks ago and was told they were in a transition of some sort, and the showroom would not be open for a couple of weeks. I wrote them again today and was told to try again in a couple more weeks.

Assuming that I do get to go down there eventually, I was wondering if anybody had any questions they might like answered while I was there.

I myself am particularly interested in the larger new CNC mills Smithy has announced, so that is what I will be spending most of my time looking at. Let me know if I can check anything out for you while I'm there... just be patient as it might take a few weeks before their showroom opens up :)

Cheers,

-Peter

No questions, but thankyou for asking.

Sure, I have some questions! Thanks for doing this!

They don't state if the smaller mills have lubrication systems or ports. Do they?

If there are no ports, can you oil the ways without removing the way covers?

Are the smaller machines gear heads or belt drive?

Are the ballscrews on the smaller machines single? What is the backlash?

Do you need two wrenches to do tool changes or is there a locking pin provision?

Can you adjust the bearing preload on the thrust bearings? Can you do it without taking a @#$%#$% clamp to the ballscrew itself?

Are the limit switches covered by the bellows or guarding over the range of travel?

What rapid speeds are they seeing on these machines?

How do they feel thier larger machines compare against the Tormach?

What do you think about the swarf/coolant guarding on the motors and wiring?

How would you tram one of these machines? What specifications for tram and machine squareness do they say they will meet?

Thanks!

-Jeff

Also, do they provide assembly drawings and instructions?

Howabout Mach 3 profiles for their control box versions?

What about replacement part availability, especially on the drivers and spindle components?

Are the drivers individually replaceable, or does the whole control box need to be swapped out?

-Jeff

Hi pjenson,

Thanks for the invite of asking q's on our behalf.

I'm with Jeff re: how the Tormach would stand up against the largest Smithycnc (1240).

Also, the Mach profiles for control box....

Since I'm from north of Toronto, Ontario, Canada (eh) I would probably never make it out that way, so thanks plenty in advance!!

jmg

Ask for a copy of a sample inspection certificate with acceptance values, assuming each machine comes with one. If it doesn't ask why not.

Regards
Phil

Hello all,

I'm local to the Smithy Ann Arbor facility, and was planning on taking a visit to their showroom. I called them a couple of weeks ago and was told they were in a transition of some sort, and the showroom would not be open for a couple of weeks. I wrote them again today and was told to try again in a couple more weeks.

Assuming that I do get to go down there eventually, I was wondering if anybody had any questions they might like answered while I was there.

I myself am particularly interested in the larger new CNC mills Smithy has announced, so that is what I will be spending most of my time looking at. Let me know if I can check anything out for you while I'm there... just be patient as it might take a few weeks before their showroom opens up :)

Cheers,

-Peter

If they don't have an inspection certificate program. I would be curious to know to what specs their machine is made to. It would be nice to know if the machine I may purcase from them conforms or does not conform to their specifications. That would be a good starting point to solve a number of problems.

Don

pjensen, ask and ye shall receive.

Update: Smithy is setting up the 1240 today. They have rented out part of their warehouse to Habitat for Humanity, and needed to relocate their showroom to a different part of the building. I plan on heading down there next week.

I have forwarded some of the technical questions to a sales rep, who should be responding early next week (needs to consult the engineers). I'll post the answers they give here, as well as my impressions of the machine when I go down there next week.

Cheers,

-Peter

Thanks Peter!

I look forward to hearing your opinions!

-Jeff

Peter,

Thanks again! I also look forward to hearing about your trip and thoughts.

Sidenote: if I understand correctly, Tormach has 640 oz-in steppers, and Smithycnc is much more (can't remember offhand what the exact number is). I wonder why the large difference??? (the extra 1/2 h.p. maybe???)

Take care,
jmg

Hello all,

I received some answers to my initial e-mail questions. I am currently scheduling a time to visit in person next week.

Here are the questions and answers from Michelle Rowe at Smithy, who has been very polite and helpful:



Dear Peter:

Again thanks for your list of questions. Some of your questions address our Smithy Base option and some address the Smithy PC Ready option. I have added notations where I think it is important to distinguish between Smithy base and Smith PC Ready. If I have overlooked anything please let me know or if you have additional questions, please let me know and we will address these questions as well.


Question 1
On the 1240 base configuration, what is the motor mounting (NEMA 34, 1/2" shaft coupling etc)? In other words, what kind of motor would the user need to provide.

Answer 1
If you are going to add your own motors you will need a coupling that will work with the 3/8" ballscrew end diameter. The mounts for this machine are NEMA 42 on all three axes.

If you are buying our Smithy PC Ready machine, the stepper motors are included as part of the package.

Question 2
Are the limit switches covered by the bellows or guarding over the range of travel?

Answer 2
Yes, the switches are covered by sheet metal guards on all three axis over the range of travel. We made the choice to use proximity switches with our machines because they do not have the metal to metal contact between the moving parts and tend to last longer then the mechanical switches.

Question 3
What rapid speeds are you seeing on these machines?

Answer 3
We do not recommend running this machine at rates higher then 120 IPM. Please note, that this rapid speed rate is only used when repositioning axes. It is never used when actually machining. When evaluating machine tools, this should not be the determining factor.

The most important factors to focus on when evaluating machine tools is the accuracy, repeatability, surface generation, longevity, as well as buying from a company that stands behind their tools.

Question 4
How do you feel that the larger machines compare against Tormach and Industrial Hobbies?

Answer 4
Both Tormach and Industrial Hobbies are putting out a nice product with similar work envelopes and power. Industrial Hobbies is using a gear head spindle and smaller work table then the Smithy CNC 1240. The gear head spindles have more mechanical parts than the belt drive system which leads to a less reliable system. They also tend to be louder. Tormach uses a belt drive system with two ranges which means you have to stop the machine to change speed ranges. We use an industrial style synchronized gear belt for stepless infinitely variable spindle speed control.

Smithy CNC 1240 is equipped with a 2 HP motor, while Tormach uses 1.5 hp motor. Smithy CNC 1240 has linear ways on the Z-Axis which provides higher accuracy and a much smoother operation than traditional dovetail ways.

It not only important to look at the products to assure that their specifications fit your requirements; it is equally important to look at the companies and their histories as well.

We were one of the first importers of machine tools from China. We have been in this business for almost 20 years. We know our machine tools and support them. We have a full staff of Smithy technicians that can be reached by calling us toll free.

Question 5
How do you tram the machine?

Answer 5
The question is implicit to a J-type Bridgeport mill. Small bed mills are built differently and the questioning of how to tram the machine is really not applicable. When you are looking at a bed mill, you want to look at squareness which is determined by the manufacturer during production. Attached to this e-mail you will find our inspection process and target values for each item related to the squareness of the machine.

Question 6
Do you provide assembly drawings and instructions?

Answer 6
Yes, we make these drawings available with a purchase of a machine.

Question 7
Are Mach 3 profiles for the control box versions available
Answer 7
Smithy Base
With our Smithy Base option we will provide you with the pinout connections from the conjunction box. It would be the responsibility of the purchaser, to configure their control system (hardware and software) to the machine.

Smithy PC
We provide the specifications for the parallel port and the number of full steps required to make the machine travel an inch or mm. we also provide some of the characteristics for spindle speed control using PWM signals. Mach3 allows the user to configure the look and feel of the system to their liking. We feel that it should be the operator's choice; therefore, we have are not have a standard configuration file set-up for Mach3.

Question 8
What is the replacement part availability, especially on the drivers and spindle
components?

Answer 8
We have always kept parts in stock for all our standard machines and it will be no different for our CNC line of machines. We will stock mechanical and electronic parts for the machines and control box, if you go with Smithy PC Ready.

Question 9
Are the drivers individually replaceable, or does the whole control box need to be swapped out?

Answer 9
The is a modular design. Individual drives can be removed or the entire assembly can be removed for trouble shooting.

Question 10
Can I get a copy of a sample inspection certificate with acceptance values?

Answer 10
Yes, please see the attached.

Question 11
Do the smaller mills have lubrication system or ports?

Answer 11
The CNC 622 does have a one shot lube system but the CNC 516 does not.

Question 12
If there are no ports, can you oil the ways without removing the way covers?

Answer 12
Our smallest mill the CNC 516 does not have a one shot lube system or oil ports at this time. You can oil the ways without removing the covers.

Question 13
Are the smaller machines gear heads or drive belts?

Answer 13
All of our machines are belt driven with life grease sealed bearings, no oil reservoirs to leak.

Question 14
Are the ballscrews on the smaller machines single? What is the backlash?

Answer 14
Yes, we build in accuracy by using a pre-loaded single nut. The backlash for the P5 ballscrews used on the CNC 1240 is approximately 0.002". Please note, this is with the ballscrew and nut installed; therefore, this number is the backlash each axis. Also, in many cases you will find that backlash becomes irrelevant depending on your control software which can compensate for lead error.

Question 15
Do you need two wrenches to do tool changes or is there a locking pin provision?

Answer 15
There are no locking pins.

Question 16
Can you adjust the preload on the thrust bearings" Can you do it without taking a clamp to the ballscrew itself?

Answer 16
Yes you can adjust the pre-load. The end bearings of the ball screw for this machine are angular contact bearings. Hence the pre-load can be adjusted by tightening the end nut on the ballscrews. You will need to determine a way to hold the ballscrew stationary while adjusting the angular contact bearings.

Veeeery interesting....

My comments:

Question 3: 120 IPM is great.... They are nuts if they don't think that matters. Yes, we try to program to avoid cutting air, but it still has to happen sometimes.

Question 5: Okay... as long as the column is on square.... that's relatively easy to fix with shims if it's off though...

Question 6: They should put them up on the website.

Question 10: Can you post this document?

Question 13: Good stuff...

Question 14: WTF????? Are you kidding me? .002" backlash? Yes, you can remove it with software, but that isn't optimal for climb cutting, and seriously degrades the performance of Mach 3. That's crazy talk on a machine that expensive. Both the Tormach and IH mills have them. Even the Syil X3 uses zero backlash double nuts.

Question 15: Bummer.

Question 16: So, yes, you do have to take a clamp to the ballscrew itself. People! Please add a pair of flats, or slot or something.

Oops, I forgot to attach the inspection sheet. It seems remarkably short to me, so I asked for confirmation that this was complete. I'll let you know if I get more.

The Smithy ballscrews are rated as P5 - does anyone have information as to what this spec requires? I think the Tormach are better at P4. Is this the most important factor in determining the final backlash?

Best Regards,

-Peter

Does this mean that Smithy doesn't have a specification for table flatness, spindle runout, etc?

I don't think P5 has anything to do with backlash, it relates to the precision of the screw (error per foot etc.). Backlash depends on preload, either with 2 nuts or single nut with oversize balls.

P4 and P5 are effectively the same. I think P4 is quite uncommon as it appears to be a none preferred designation. You can find the actual numbers on most ballscrew manufacturers sites, although many don't even bother to quote P4.

Regards
Phill



The Smithy ballscrews are rated as P5 - does anyone have information as to what this spec requires? I think the Tormach are better at P4. Is this the most important factor in determining the final backlash?

Best Regards,

-Peter

Short? its a bit of joking I think. If Smithy want to claim they are professional then they need to provide an inspection certificate with the appropriate content.

Regards
Phil

It seems remarkably short to me, so I asked for confirmation that this was complete.
-Peter

I don't think P5 has anything to do with backlash, it relates to the precision of the screw (error per foot etc.).

Ok, that makes sense. I wonder if the 0.002" backlash spec is under maximum load or some such. Honestly, I've heard the expression "zero backlash ballscrews" so many times, I didn't know there was any other kind of ballscrew setup.

The system they have set up now is apparently a non-running system (no motors). I'll to take a look anyway. I don't think there is any way for me to test backlash on such a system... I can bring down a test indicator and push back and forth on the ways, I suppose...

Best Regards,

-Peter

FYI, the IH CNC conversion also claims 0.002" backlash. I think they used to offer a different ballnut with less, with the caveat that the lower backlash configuration was not as suitable for high machining forces.

Does anybody know what the Tormach spec is, for comparison?

Cheers,

-Peter

Maximum allowable values for the Tormach are:

x:0.03 mm = 0.0012"
y:0.03 mm = 0.0012"
z:0.04 mm = 0.0018"

Look here:

http://www.tormach.com/document_library/PCNC1100_CertInspect_V3.pdf

Note that you have to distinguish between just ball-screw backlash and total machine backlash.

Regards
Phil

FYI, the IH CNC conversion also claims 0.002" backlash. I think they used to offer a different ballnut with less, with the caveat that the lower backlash configuration was not as suitable for high machining forces.

Does anybody know what the Tormach spec is, for comparison?

Cheers,

-Peter

There's a lot of info happening here...
"your best consumer is the best informed consumer" (somebody else's quote)

Thanks Peter for your efforts to find out what the scoop is! It certainly is appreciated. Thanks to all others involved as well.

jmg

Hello all,

I went down to the Smithy showroom today and spoke with Michelle Rowe, who was very helpful.

The machine on the floor did have the motors installed, but no control box so I could not see it actually run. With that in mind, all I could do was look it over without running it.

The finish on the machine was good, and I could not see any quality problems. The amount of metal under the X axis ways may have been a little less than I would have liked (the space left for the ball-screws was more than strictly needed) but I can't say that this would actually cause any problems without running the machine.

My guess is that you would see some stiffness issues only when running the machine under very heavy loads. I wouldn't expect much trouble if the cutting loads are kept to "normal" levels. I haven't viewed an IH or Tormach, so I can't directly compare.

The Z-Axis ways were also lacking a cover, so the ball screw was exposed. Michelle correctly pointed out that the head itself will usually block chips/coolant from hitting the screw, but I think a user of this machine may want to rig up some kind of cover for the Z axis. The X and Y axes were well covered with a plastic bellows.

Those were the two potential problems I saw with the machine. One is easily fixable, and the other may be minor (we won't know until somebody can actually run the machine and make cuts...)

Overall the machine was well put together, with some attention to detail such as wire conduit and covered connection points for the wiring placed on the back of the column. Fit and finish was good, including the stand. Certainly a hobby user, Smithy's primary audience, would be very happy with this machine.

As it turns out, the inspection sheet I received earlier was incomplete, as I suspected. I will attach a scan of the complete inspection sheet.

In other news, Smithy's future plans include a line of light-industrial machines (which should have Servo's) sometime in the next couple years. Also, they are in the late stages of a quick-change tooling system similar to the Tormach tooling system.

I hope this information is helpful.

Best Regards,

-Peter