[pjensen]

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.