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bumperscoot
04-06-2007, 07:20 PM
Hi All!

I am nearing the home stretch in a "Fact Finding" mission to determine which CNC mill machine I will purchase. I plan to use my mill for light production and prototyping while I test the waters and potential business plan for my small startup company.

I have narrowed my search to a few machines, the front runners being IH and Tormach. I did visit IH and was suitably impressed with the newer and beefier version of their mill, and it has been my target machine to date. I do plan to visit a local company tomorrow that operates a Tormach in a production environment, I am anxious to see its application and observe it under power.

I would like to ask the members of this community if they could describe their operating experiences (both good and bad) with their IH mill. How is its accuracy/repeatability under power? When machining a long part (i.e., ~17" in length), what kind of end/end runout are people seeing?

Tormach was very forthcoming with their customer contacts and user base allowing me to ask real world questions to real operators while drawing from their kudos and gripes. I have asked the same to IH, and have not received any data as of yet.

I would appreciate feedback from current IH users (preferably those in commercial service), specifically from those using the newer mill (as that is what my purchase decision is based upon). I look forward to reading your replies!

Best Regards and Thank you in advance,

Steve

ppsi
04-06-2007, 09:56 PM
Steve-
You haven't talked about the type of parts you want to make with your mill. I think the answer to your question will come from looking at the demands your business plan will put on your cnc machine and a good understanding of the difference between servo and stepper control. The fact that you have a business plan indicates you do your homework. Your next assignment is to review your product and determine your needs with respect to throughput and tolerance. Good Luck.

bumperscoot
04-06-2007, 11:13 PM
ppsi,

Good point..

I'm not anticipating mill runs 24x7 (although I could only hope!), I am planning at most 20-30 hrs/week.

The majority of the work I plan to produce are parts for automated opto-mechanical parts for large-aperture telescopes. The remainder of the machine work time will be spent refining a few low-tech, low-accuracy parts for truss-pole mountings and cPCI chassis front panels.

Much of my opto-mechanical and electro-mechanical assemblies are interference fit parts and require an accuracy or tolerance not to exceed + 1.5thou over 4" max (my most critical part). this needs to be fairly repeatable.

The low-tech stuff can have a fair amount of "slop" without issue.
One of my assemblies is a long bar-shaped part ~17" long. While the absolute dimension is not critical, the parallelism of the top/bottom faces should stay within +/- 2 thou over the length.

I guess at this stage in my homework I am looking for the anecdotal experiences of the user (as this is the real-world experience under real-world conditions data I am looking to hear) and how consistent from user to user it is.

Steve

SMW Precision
04-09-2007, 02:06 AM
Hi All!

I am nearing the home stretch in a "Fact Finding" mission to determine which CNC mill machine I will purchase. I plan to use my mill for light production and prototyping while I test the waters and potential business plan for my small startup company.

I have narrowed my search to a few machines, the front runners being IH and Tormach. I did visit IH and was suitably impressed with the newer and beefier version of their mill, and it has been my target machine to date. I do plan to visit a local company tomorrow that operates a Tormach in a production environment, I am anxious to see its application and observe it under power.

Steve

Let us know your conclusions as you complete your research. I will be posting a longer message on IH components and build in the next week or so. I own the IH CNC kit and was allowed full information on what components are used in the CNC kit and frankly I am amazed at the quality and value.
Let's look at ballscrews; from posted Tormach information they use a medium accuracy ballscrew, I did not find the diameter or manufacturer listed. While IH supplies an American made Premium grade Rockford 3/4" ballscrews with a static load rating of 1950 lbs. Ballscrew selection has a major effect on both accuracy and operation life.
Compare closed-loop servo versus an open loop stepper power system. The IH mill is unlike anything else available in size, rigidity or price. All CNC components are high grade and all US built. Machining for mechanicals is completely done on an IH mill.

philbur
04-09-2007, 06:59 AM
As a happy Tormach user I feel obliged to put the record straight:

Tormach has 3/4" ground ballscrews with a precision P4. IH are rolled ballscrews (so probably T grade) with no stated precision grade. P grade is normally used on precision motion systems and T grade on general purpose transport systems. P grade have a maximum allowable cumulative error T grade do not and (from memory) are normally not better than precision 7. P4 on machines of this quality would never be considered as medium accuracy. If this were the case then the rolled ballscrews would be the equivalent of using a tape measure for positioning.

The Tormach has a maximum backlash of 0.001" in the x and y and 0.0015" in Z. This is the total system backlash, allowing for the mount bearings and stretch/compression of the system due to stiction etc. Mine measured at equal to and better than the maximum allowable. The best option for the IH has a stated 0.002" in the ball screw alone.

Tormach issue a comprehensive test certificate with every machine, a sample certificate can be down-loaded from their website. It would be useful if IH produced a similar certificate to allow potential buyers to make a direct quantitative comparison.

Regards
Phil




Let's look at ballscrews; from posted Tormach information they use a medium accuracy ballscrew, I did not find the diameter or manufacturer listed. While IH supplies an American made Premium grade Rockford 3/4" ballscrews with a static load rating of 1950 lbs. Ballscrew selection has a major effect on both accuracy and operation life.

SMW Precision
04-11-2007, 01:02 AM
I have been researching ball screws a bit more before commenting back. Rockford ball screws are rolled version. IH Mills and kits come with Rockford’s Premium grade ball screws with a potential linear deviation between 0-0.003" in 12 inches. All of mine were under an .001" in 12" deviation.
Maximum potential backlash from Manufacturer specification is .001. Linear error is far more complicated than just a 12" lead error measurement would lead you to believe. All ball screw CNC setups can benefit greatly from table mapping and parameters setting. Deviation may be either plus or minus in any rotation. On a 5 TPI; 12 inches is 60 rotations.
Rockford Ball screws are commonly used in many CNC retrofits as well as by CNC equipment manufactures. The other factor in ball screw is Dynamic and Static load ratings which are key to determining ball screw life span. IH ballscrews with a 1950 lbs Static load rating will run for tens millions of inches of travel before degrading.

bumperscoot
04-11-2007, 08:52 PM
I too have done a bit of homework on this issue, and have found this point mostly irrelevant for this implementation. The major benefit of a P grade vs. a T grade ballscrew is the control of accumulated error along the screw. Since this measurement is typically performed over a 1 meter section, the errors involved for either application are minimal if not non existent..

The following articles were of interest.

http://www.machinedesign.com/ASP/strArticleID/56939/strSite/MDSite/viewSelectedArticle.asp

http://www.machinedesign.com/ASP/strArticleID/56489/strSite/MDSite/viewSelectedArticle.asp

LUCKY13
04-11-2007, 11:32 PM
Bumperscooter, what is it that is much better on the new IH machine. I will soon be making the same choice as you are is why I ask. It seems that the price of the full CNC heavy machine is getting up there a bit. So I wander what would be the reason for buying one. Wiht the price getting around the 12,000 range, I wander about the software that goes with it. I am afaid this area is something I dont know much about (software). So I worry about what is capable with a system like this compaired to something like Centroid/Ajax,Traxs or other retro fit systems. ALthough I will be starting out the basic things I want to be able to expand when the time comes. The whole thing is a bit overwellming to a new comer and it worries me about getting stuck with something that want fit the bill. Of course the machine itself will have a lot to do with things, but it goes beyound that in the end.


Jess

SMW Precision
04-12-2007, 01:29 AM
What is it that is much better on the new IH machine. I will soon be making the same choice as you are is why I ask. It seems that the price of the full CNC heavy machine is getting up there a bit. So I wander what would be the reason for buying one. Wiht the price getting around the 12,000 range, I wander about the software that goes with it. I am afaid this area is something I dont know much about (software). So I worry about what is capable with a system like this compaired to something like Centroid/Ajax,Traxs or other retro fit systems. ALthough I will be starting out the basic things I want to be able to expand when the time comes. The whole thing is a bit overwellming to a new comer and it worries me about getting stuck with something that want fit the bill. Of course the machine itself will have a lot to do with things, but it goes beyound that in the end.


Jess

Look at the Standard IH mill and not the heavy duty version. Unless you have some specialized needs. I know it gets confusing and the more you compare the more confusing it gets.
Current IH machines come wirh Mach 3 and Dolphin Cad/Cam level 2 Milling which is 21/2D Cad and Cam conversion. Mach 3 is Windows based, friendly and flexible. Provides the conversational features and much more. Advantage or this program is it is being constantly upgraded with almost all upgrades being free. Both of these programs have free downloads to play with and lots of user comments on CNC Zone and many other places. I believe IH is the only one currently supplying a CAD/CAM package with Mill purchase.

philbur
04-12-2007, 03:28 AM
My main conclusion is that secondary suppliers of ballscrews and suppliers of CNC machines should state the grade and precision designation so that the potential buyer can properly compare and assess. The phrase "super precison" has no meaning and indicates only an intention to hide and/or confuse.

Regards
Phil

PS: The difference between P grade and T or C grade starts to become relevant for travel distances over 300 mm not 900 mm.

Regards
Phil


I too have done a bit of homework on this issue, and have found this point mostly irrelevant for this implementation. The major benefit of a P grade vs. a T grade ballscrew is the control of accumulated error along the screw. Since this measurement is typically performed over a 1 meter section, the errors involved for either application are minimal if not non existent..

The following articles were of interest.

http://www.machinedesign.com/ASP/strArticleID/56939/strSite/MDSite/viewSelectedArticle.asp

http://www.machinedesign.com/ASP/strArticleID/56489/strSite/MDSite/viewSelectedArticle.asp

SMW Precision
04-12-2007, 11:18 PM
This thread has peaked my interest in the Tormach mill. Perhaps some one with more engineering and ballscrew experience would take a look at the Tormach setup. It is shown in owner’s manual section 9.55. I don't understand the setup at all from details given.
Preload specifications are for a 0.0004 to 0.0008 backlash and X-axis setup does not seem to be a conventional double nut ballscrew. Appears from pictures and diagram to a have a very small ball load. They describe it as a free floating ballscrew system.
Also unconventional on the Tormach mill are Plastic machine Ways. According to their information they are using 0.031" PFTE attached on Way as a bearing surface. I've tried several web searches and can not find any relevant information on this usage. I use PFTE for various things; though it would worry me with this type of machine application.

philbur
04-13-2007, 02:28 AM
The PTFE coating is similar to Turcite B Slydway, which is commonly used on "upmarket" machine tools slideways. It has some very significant advantages over metal to metal contact. It is not unconventional just uncommon in the hobby arena. I would not be worried about the concept. The real issue would be how well has it been implemented.

I can't find any reference in the user’s manual to "a free floating ballscrew system"

If you have not already found it you may find this document interesting:

http://www.tormach.com/document_library/Personal%20CNC%20Design_v1.pdf

Some would claim it is highly slanted, but it is quite logical and at least give food for thought for us “know nothing” amateurs.

Regards
Phil


They describe it as a free floating ballscrew system.
Also unconventional on the Tormach mill are Plastic machine Ways. According to their information they are using 0.031" PFTE attached on Way as a bearing surface. I've tried several web searches and can not find any relevant information on this usage. I use PFTE for various things; though it would worry me with this type of machine application.

philbur
04-13-2007, 02:44 AM
All three ballscrews have double nuts with a ground spacer for preload. The preload setting is described as medium, this preload setting is the source of the backlash. It's described in the document link in my previous post.

Regards
Phil


and X-axis setup does not seem to be a conventional double nut ballscrew.

davo727
04-13-2007, 06:37 AM
When forum members are looking for user opinions on machines to help with a purchasing decision, people posting messages should disclose if they have business ties with any of the mentioned companies. This is the right thing to do. Thanks, Dave

davo727
04-13-2007, 06:53 AM
Oh, I dont have any monetary ties with Tormach or Industrial Hobbies. Dave

philbur
04-13-2007, 08:09 AM
I would agree when a person is making a recommendation regarding a particular product. However I disagree in situations where a person is stating a fact regarding a product.

Regardless, at the end of the day it is a case of "reader beware". Searching the archives can often give you a clue as to who is talking to you. If you don't know anything about the person giving you advise then ..... well need I say more.

Regards
Phil


When forum members are looking for user opinions on machines to help with a purchasing decision, people posting messages should disclose if they have business ties with any of the mentioned companies. This is the right thing to do. Thanks, Dave

bumperscoot
04-13-2007, 11:37 AM
First off, I am in no way affiliated with either company. Period.

I am an engineer looking to build a small startup company manufacturing electromechanical/optical assemblies for various custom solutions. I'm not sure if the previous comments were directed at my previous posts/inquiries or not, but I thought I would state this plainly.

As with any large purchase, I want to make the most correct and informed decision, especially since this is my money. Education is a large component in that process, and "Pinging" the forums found on this site was a portion of the research which my decision is based on.

I have been lucky enough to have had access to both the IH and Tormach products and walked away with a very clear understanding of "fact and fiction" concerning the expected performance and capabilities of these (IH and Tormach) machines.

At the end of the day, I chose the Tormach for a host of reasons.

Don't misunderstand me, as both machines are quite capable. But I could not dismiss IH's reluctance to publish any performance specs or provide an inspection sheet. As an engineer with more than 20+ years experience, I could never recommend a product from a manufacturer who refuses to publish a specification for some level of expected performance, and it is doubly true for my own company.
I also was impressed with the response from commercial Tormach users who allowed me to "poke and prod" not only at their machines, but at their decision/thought process around their purchase, and the way in which their machines are used. I honestly expected a better response from the IH community, as their product is supposedly more widely deployed in commercial production environments and applications.
Lastly, I could also debate this servo motor vs Stepper issue all day, but the fact remains that this purchase is a tool to complete a task. Both tools will accomplish the same task within some performance envelope, and I do not find documented or anecdotal evidence to suggest these envelopes are very dissimilar. For my money, the Tormach is a better fit for my needs.

leeschaumberg
04-13-2007, 12:31 PM
CNC Zone
It's fun to tell the truth and say that I am not financial associated with anybody. There is a wise old saying that goes - For enough money some people will say or do any thing! Including kill themselves! Boy that felt good.:)

Paul in OK
04-13-2007, 12:54 PM
I am following this as well. Looking at both the Tormach and the IH. One thing I am impressed with is the video on the IH site, and that they use their own machines to make parts for the cnc mills. Says a little to me anyway.

philbur
04-13-2007, 01:32 PM
Have you looked at these on the Tormach site:

http://www.tormach.com/mfg_database.htm

Regards
Phil


I am following this as well. Looking at both the Tormach and the IH. One thing I am impressed with is the video on the IH site, and that they use their own machines to make parts for the cnc mills. Says a little to me anyway.

RICHARD ZASTROW
04-13-2007, 02:26 PM
There's another "old saying" advice is only worth what you paid for it ; or less.) There, I'm old and I said it. By the way I think the new IH and Tormach both sound like resonably good machines for the money. How's that for an inert statement?

Paul in OK
04-13-2007, 03:08 PM
Have you looked at these on the Tormach site:

http://www.tormach.com/mfg_database.htm

Regards
Phil
Just looked. Good stuff. Thanks.

SMW Precision
04-13-2007, 10:25 PM
[QUOTE=philbur;285010]The PTFE coating is similar to Turcite B Slydway, which is commonly used on "upmarket" machine tools slideways. It has some very significant advantages over metal to metal contact. It is not unconventional just uncommon in the hobby arena. I would not be worried about the concept. The real issue would be how well has it been implemented.

Turcite product is used in upper end machines something I did not know yesterday. Use of PFTE is a similar concept though it concerns me that you may not have similar results. Turcite may be used with or with out lubrication. Where direct plumbing of lubricant into Tormach ways would indicate using PFTE dry could have a poor result.

I can't find any reference in the user’s manual to "a free floating ballscrew system"

Reference is on page 11 in Design Analysis, Hand Wheel section. Mentioning ball screw mounting design. They were able to significantly reduce the cost of the ballscrew mounting system. Trade off is that ballscrew must be operated below 120 ipm or problems may occur. With a listed speed of 65 imp it seems a reasonable trade all other factors being equal.

Phil,

I am very conservative on machine tool design. I like rigid things and well proven concepts. In general this has kept me out of trouble.

Regaurds,

SMW Precision
04-13-2007, 11:17 PM
When forum members are looking for user opinions on machines to help with a purchasing decision, people posting messages should disclose if they have business ties with any of the mentioned companies. This is the right thing to do. Thanks, Dave

Dave,

I am an IH vendor providing DRO systems for their manual mills. My CNC Zone user name is also my business name and SMW Precision is clearly shown on the IH website. That said I purchased and IH kit over a year ago. Long before I became a Vendor last month and have watched and explored the IH product for over 4 years.
I neither represent IH nor have any ownership interest. While I am participating in sense of seeing that fair factual data is being brought out. Machining is part of my business process as well as a hobby.

Happy machining,

philbur
04-14-2007, 05:46 AM
This is a reference to the fact that the ballscrews are supported at one end only, hence the other end is "floating"

Regards
Phil


Reference is on page 11 in Design Analysis, Hand Wheel section. Mentioning ball screw mounting design. They were able to significantly reduce the cost of the ballscrew mounting system. Trade off is that ballscrew must be operated below 120 ipm or problems may occur. With a listed speed of 65 imp it seems a reasonable trade all other factors being equal.

philbur
04-14-2007, 05:57 AM
I think using it dry depends on the application. I have seen three or four machine tools that had Turcite coated ways, they all had slideway oil lubrication systems as well.

Regards
Phil

[QUOTE=SMW Precision;285392
Turcite product is used in upper end machines something I did not know yesterday. Use of PFTE is a similar concept though it concerns me that you may not have similar results. Turcite may be used with or with out lubrication. Where direct plumbing of lubricant into Tormach ways would indicate using PFTE dry could have a poor result.
QUOTE]

Randall
04-17-2007, 12:56 PM
Philbur
Can the tormach take flood cooling , Does it have steppers or servos, and isnt it smaller travels than IH mill. Maybe thats why you have to come to our group to get customers, cause when it comes down to the IH mill keeps improving in quality. And the more you come in here pushing tormach the more I dislike the company and its tools and you. Yet I would never go to the tormach discussion to compare and push IH.
Randy

Paul in OK
04-17-2007, 01:01 PM
What's worng with a comparison of one machine by an owner of another? I don't own either, but if I did, I would still visit both areas just for the learning curve brought out by one asking questions.
Paul

Randall
04-17-2007, 01:20 PM
There is nothing wrong with comparison but the party in question posts here are not always fair comparisons and He mosl\tly shows up when somebody is asking about IH. I want comparisons from users that dont have a stake in the mill they are pushing.
Randy

RICHARD ZASTROW
04-17-2007, 01:33 PM
FYI Turcite works fine dry. It slides better than cast iron. When you add oil to the Turcite/slideway interface, it slides with less friction further reducing the dreaded "stick-slip". It's not perfect but it is an improvement. Ball or roller guideways move easier than Turcite but do not have the vibration dampening qualities of the sliding contact.

SMW Precision
04-17-2007, 03:40 PM
FYI Turcite works fine dry. It slides better than cast iron. When you add oil to the Turcite/slideway interface, it slides with less friction further reducing the dreaded "stick-slip". It's not perfect but it is an improvement. Ball or roller guideways move easier than Turcite but do not have the vibration dampening qualities of the sliding contact.

True, but the discussion was use of PFTE for Tormach. While the concept is similar the products are different. Perhaps someone has knowledge of PFTE used in Machine Ways. I have yet to find any reference.
Even with Turcite there are failures. I heard about one machine that Ways were contaminated by cast iron swarf. Three weeks production lost with a cost of 230,000.00.

llino
04-17-2007, 05:01 PM
True, but the discussion was use of PFTE for Tormach. While the concept is similar the products are different. Perhaps someone has knowledge of PFTE used in Machine Ways. I have yet to find any reference.

Actually, I believe that the Tormach uses a PTFE and delrin blend, that is similar to Turcite. I think (that is, as I understand) the difference between the plastic used on the Tormach and Turcite is the difference between Teflon and PTFE. Turcite is a trade name, the stuff used by Tormach is not a name brand, but nearly identical from a performance standpoint.

To put out the standard disclaimer that is getting to be needed in this thread:
I don't work for either Tormach or IH.
I've owned an IH manual mill, but no longer do.
I'm about as close to telling you IH is better than Tormach as I am to saying Ford is better than Chevy... wait, or was it the other way around...

I do own a B'port that has turcite (or similar) on the ways and I am very happy with it. I also believe that the turcite is the only reason that the mill is still usable after the life it lived before I got it.


It's true that stuff can stick in the turcite and eventually damage things, however versus cast iron on cast iron, it's far more tolerant. One of the beauties of turcite is that foreign particles can embed in the bearing surface instead of immediately causing a problem.

ciao

lino

SMW Precision
04-17-2007, 06:30 PM
Actually, I believe that the Tormach uses a PTFE and delrin blend, that is similar to Turcite. I think (that is, as I understand) the difference between the plastic used on the Tormach and Turcite is the difference between Teflon and PTFE. Turcite is a trade name, the stuff used by Tormach is not a name brand, but nearly identical from a performance standpoint.

To put out the standard disclaimer that is getting to be needed in this thread:
I don't work for either Tormach or IH.
I've owned an IH manual mill, but no longer do.

ciao

lino

Point that I have made several times and you choose to ignore. Similar in concept is not necessarily the same in application. Turcite needs no lubrication that is a known factor. While Tormach plumbed oil directly to the Ways. Plumbing Ways added expense in Mill construction which would lead a reason man to conclude material they are using should not be run dry.
No performance data is given on this material or any reference to its ability to operate in a non lubricated state. Many years ago I learned what Assume means.

I do not work for IH and I do own the IH CNC kit.

IH DRO System Vendor

RICHARD ZASTROW
04-17-2007, 09:36 PM
I don't work for anybody unless I feel like it. Ken got me nosing around and according to most of the Thompson, Saint-Gobain, Igus and NTN Bearee info I have laying around, PTFE and Turcite a, b and x all can be used dry but have better co-efficient of friction and less stick slip if lubricated with oil. There are MANY variations of PTFE in additives and compounding. I have no idea which of these are used on these mills. Hope that helps a little.

llino
04-17-2007, 09:50 PM
Point that I have made several times and you choose to ignore. Similar in concept is not necessarily the same in application. Turcite needs no lubrication that is a known factor. While Tormach plumbed oil directly to the Ways. Plumbing Ways added expense in Mill construction which would lead a reason man to conclude material they are using should not be run dry.
No performance data is given on this material or any reference to its ability to operate in a non lubricated state. Many years ago I learned what Assume means.


Hello Ken,

I didn't ignore that point I don't believe. Every application of turcite that I've seen (which I'll admit is enough to count on my hands) also had direct lubrication.

Perhaps the misunderstanding is here: Turcite doesn't *need* lubrication but it certainly helps and is recommended in almost all situations. (some food service bearing uses come to mind as a non-lube recommended apps.) I think the advertising point for Turcite is that *if* it is run dry the system will not destroy itself in short order, as would be the case in metal on metal systems. It does however perform better with lube. As I said earlier, most machine tool uses of Turcite are also lubricated. I certainly don't think that Tormach is trying to "pull one over" on anybody by lubing a machine with turcited ways.

Clearly we are beginning to split hairs with the material name here too. Isn't it usually the case that common properties are accepted between tradename materials and generics. In fact trade names are more often the common usage of the word. You don't get upset if someone uses acetal instead of Delrin, or acrylic instead of Plexiglass, right?

ciao

lino

MichaelHenry
04-17-2007, 11:54 PM
Philbur
Can the tormach take flood cooling , Does it have steppers or servos, and isnt it smaller travels than IH mill. Maybe thats why you have to come to our group to get customers, cause when it comes down to the IH mill keeps improving in quality. And the more you come in here pushing tormach the more I dislike the company and its tools and you. Yet I would never go to the tormach discussion to compare and push IH.
Randy


Phil can speak for himself, of course, but I'm pretty sure that his only relationship to Tormach is as a user of one of their mills. I am a Tormach user as well and visit here just to see what is up in the IH world.

Mike

skullworks
04-18-2007, 01:02 AM
Well I like the higher RPM, quiet dual range spindle on the Tormach...

Floating ( unsupported ) ballscrews - Don't like.

Open loop Stepper drive with about half the rapid speed - Don't like.

Reuced travel capacity - Don't like.

Bastard toolholders - Don't like.

Ok - So I was able to find ONE good thing about the Tormach I like. - One is not enough.

I have no ties to either company. I DO have an IH manual machine on order.

llino
04-18-2007, 07:14 AM
Floating ( unsupported ) ballscrews - Don't like.



Not to keep playing devils advocate here, but before we hang Tormach in effigy...

I haven't heard any of the IH spec gurus speak up here, doesn't the IH cnc conversion have floating ballscrews too?

From previous reads of the instructions I believe that's the case on every axis.
Furthermore, something no one seems to acknowledge, is that "one end free" ball screws are just fine in these applications. That is, where feeds are low enough, and the ball screws are short enough and the diameter of the screw is large enough.

It's a simple equation provided by the ball screw manufacturer. It's a go, no-go type function of:
screw diameter (larger the better)
maximum unsupported length (shorter the better)
maximum rotation speed (slower the better)

In fact if you look at those three, the IH may be closer to needing another bearing, as on at least the last two, if not all three, it has the "worse" values.

ciao

lino

wildcat
04-18-2007, 09:54 AM
I haven't heard any of the IH spec gurus speak up here, doesn't the IH cnc conversion have floating ballscrews too?

From previous reads of the instructions I believe that's the case on every axis.


Yes (at least the kit from Aaron had unsupported ends - perhaps this has changed...)

philbur
04-18-2007, 10:15 AM
Hi Randall,

I have no connection with Tormach other than being a happy user. The originator of this thread was asking about IH vs Tormach. I gave factual answers about the Tormach.

When the Tormach is discussed on this group and somebody misunderstands some aspect of it, or asks a question I will continue to correct the misunderstandings and give answers. I'm sorry you don't like it but that's not my problem.

Regards
Phil

PS:I would be interested to read any unfair comparison I have made, do you have a post number reference. At least you seem to accepted that most of them are fair comparisons, so are presumably useful information.


There is nothing wrong with comparison but the party in question posts here are not always fair comparisons and He mosl\tly shows up when somebody is asking about IH. I want comparisons from users that dont have a stake in the mill they are pushing.
Randy

philbur
04-18-2007, 11:05 AM
Hi again Randy,

Have you not studied the Tormach in any detail. Here's a link you may find useful:)

www.tormach.com

Yes it can take flood coolant, it even comes with way covers and one shot lubrication, which I'm sure you know are important factors with FC. Yes it has steppers and smaller travels but neither of these is a limitation for the class of work that I do. In fact the 1100 lbs weight of the Tormach combined with a compact design makes for a very rigid machine, you can only spread the jam so thinly you know.

Regards
Phil

Ps: Once again, I have no connection with Tormach other than being a happy user.


Philbur
Can the tormach take flood cooling , Does it have steppers or servos, and isnt it smaller travels than IH mill. Maybe thats why you have to come to our group to get customers, cause when it comes down to the IH mill keeps improving in quality. And the more you come in here pushing tormach the more I dislike the company and its tools and you. Yet I would never go to the tormach discussion to compare and push IH.
Randy

MAX711
04-18-2007, 11:12 AM
A bit late to this thread, but for what it's worth, I've owned both machines and can talk from experience.

Before I do give my opinion, I have been told that the "new" IH machines are much better than the older one I had. So I cannot comment on the newer machines.

It's been my observation from being on this site for a few years now that people get quite emotional about defending either IH or Tormach. I can only attribute this to a subconscious desire to justify the time and money they have invested in said mill. I've even seen people who don't have a machine get irate about some specification or tolerance they've read on the company website.

I'm not going to go line by line through all the differences, weaknesses or strengths. What I will say is that I could not get my cnc converted IH mill to work well for me so I bought a Tormach. I never looked back, the difference, for me, was stunning. I became so annoyed at myself for wasting so much time and money on the IH conversion that I stripped off all the good bits and took the rest to the scrap yard.

I know that's not what the IH fans wanted to hear and I'm sure I'll get berated for being an "idiot" or "biased trouble maker", but I really don't care. I only wish I had made the change earlier. The Tormach is a great machine for the price that is ready to go out of the box. Maybe the new IH is too, but the old one definitely wasn't.

Take what you want from this.

RICHARD ZASTROW
04-18-2007, 11:26 AM
Are you sure "floating" means "unsupported"? Some screws (most) are floating in that the end of the screw has a bearing on it that is allowed to float axially. Some (few) are installed with tension on the screw requiring that the end bearing be "fixed" rather than "floating". Just a thought.

dnelso
04-18-2007, 08:52 PM
I have a IH mill and bought the cnc kit from Aaron. He never posted specs because he only sold kits. I hope the new owners will publish specs now that they sell assembled machines. I made several changes when i built the machine. I made steel housings and mounts for the ball srews and made supports with bearings for the end of the ball screws.Changed motor and added a VFD I have been very happy with the mills perfomance. I almost bought a Tormach but it does not have servo drives and the 65 ipm is very slow. I do alot of 3d machining and 100ipm rapids is ok but i wish now it was even faster.
Later DN

philbur
04-19-2007, 10:04 AM
Hi DN,

I can understand the desire for fast rapids if a person does a lot of coordinate type work. I don't currently do any 3D work but assumed that most of the time the cutter is buried in the work piece, running at relatively low feeds, so it is not clear to me why you feel even larger that 100 ipm would be good. What have I missed with respect to 3D work.

Best Regards
Phil


I have a IH mill and bought the cnc kit from Aaron. He never posted specs because he only sold kits. I hope the new owners will publish specs now that they sell assembled machines. I made several changes when i built the machine. I made steel housings and mounts for the ball srews and made supports with bearings for the end of the ball screws.Changed motor and added a VFD I have been very happy with the mills perfomance. I almost bought a Tormach but it does not have servo drives and the 65 ipm is very slow. I do alot of 3d machining and 100ipm rapids is ok but i wish now it was even faster.
Later DN

dnelso
04-19-2007, 08:05 PM
When you are doing finish passes on some 3d parts and you want to cut the same direction it cuts and then rapids back and cuts again. Not all parts require this but alot of the parts that i make do.
Later DN

philbur
04-19-2007, 08:48 PM
Thanks for the explanation.

Regards
Phil


When you are doing finish passes on some 3d parts and you want to cut the same direction it cuts and then rapids back and cuts again. Not all parts require this but alot of the parts that i make do.
Later DN

Cruiser
04-20-2007, 08:18 AM
The Floating ball screw is a "NON ISSUE" or "IRRELEVENT" to performance ! What it does do is to allow for any alignment issue that may be, for the fact of being a kit !

kimoyo
04-24-2007, 01:29 PM
I haven't posted on cnczone lately but I still see the same stuff going on. I brought an LI kit and mill from Aaron late last year. I haven't put it together yet but I had some questions and since IH is close to me now I went on a visit. All I will say is that I saw perfect 2.5" circles being cut from 3/4-1" thick aluminum stock at 140ipm with a 1/2" endmill. They do a rough cut of about 0.25" at 60ipm and then the finishing cut of 0.10" at 140ipm. The proof is in the pudding, I don't care about them not releasing specs, I care about parts that are made and how fast. And I've seen tons of parts made on IH mills because they use ih mills to make ih parts.

As far as ballscrews go, I know I can get the manufactures of the IH ballscrews on the phone and they will provide with an independent verification of specs and guarantees for me because I've already done it. Can I do that with a Tormach mill or can I only get the guarantee from Tormach?

philbur
04-25-2007, 03:13 PM
Which model IH mill was that.

Regards
Phil


I haven't posted on cnczone lately but I still see the same stuff going on. I brought an LI kit and mill from Aaron late last year. I haven't put it together yet but I had some questions and since IH is close to me now I went on a visit. All I will say is that I saw perfect 2.5" circles being cut from 3/4-1" thick aluminum stock at 140ipm with a 1/2" endmill. They do a rough cut of about 0.25" at 60ipm and then the finishing cut of 0.10" at 140ipm. The proof is in the pudding, I don't care about them not releasing specs, I care about parts that are made and how fast. And I've seen tons of parts made on IH mills because they use ih mills to make ih parts.

kimoyo
04-26-2007, 10:10 AM
It was the same LI / Heavy Duty model they sell but with a belt drive conversion. And that flood coolant was impressive, not a little trickle. If you don't close the door it can splash all over you.

Which model IH mill was that.

Regards
Phil