Messages

21

General Mach Discussion / Re: saving spindle auto calibration

« on: July 02, 2009, 09:31:38 AM »

with smooth stepper, spindle is spot on after I calibrate and good up until I shut down and restart mach , then has to be recalibrated

22

General Mach Discussion / saving spindle auto calibration

« on: July 01, 2009, 09:53:53 PM »

After running the spindle  calibration is there anyway to save the setting so it doesnt have to be run each time mach is launched? I have clicked the save setting box that pops up when done and clicked save settings from the pull down menu  but everytime I launch mach it seems I need to run the spindle auto calibrate routine

23

General Mach Discussion / Re: Parallel port for PCI bus that works with Mach3 - just passing along info

« on: July 01, 2009, 06:19:47 PM »

http://www.newegg.com/Product/Product.aspx?Item=N82E16815166007

I have been running this one for a while now , you can occasionaly find it at cyberguys for less than $10 , mine didnt work with the driver supplied on the cd either but works well with the one on the chip manufacturers website

24

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 29, 2009, 10:37:01 PM »

pretty far off the original topic of a new power drawbar design , but here is a link to a company that sells the grippers that pull the retention knobs used on cat and bt tool holders. They are avail in a variety of sizes and types

http://www.ortlieb.net/

25

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 29, 2009, 11:32:35 AM »

The dog pin and R8 has been argued over many times on many forums, all I can say is on all Bridgeports I had and any I have seen the pin has been removed and I have never had an issue with a collet spinning whilst tightening the drawbar, both manually and with a power drawbar.

Hood

I agree , the pin isnt present in either of mine and we have never had one spin while using the impact type power drawbar, also never had a cross thread or thread stripping issue , although we use tool holders intead of collets so they really dont kneed to be that tight.

Another thought might be to swap to a cat 30 spindle if avail for your machine , I know acra has them for their bridgeport clones and tool holders are fairly cheap

26

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 29, 2009, 11:22:43 AM »

This seems similar to this system.
www dot mach-1tooling dot com

I have used it and it works extremely well. Very rigid and accurate. Quick tool changes too.

Kenny

Kenny,

I find that system fascinating.  The pullstud mechanism is precisely what I had in mind for a future "upgrade" to my setup, and proves that it CAN be done.  What really surprises me is the very low drawbar tension - apparently only 600#?  After my testing the last few weeks, I'm amazed that's enough to securely hold an endmill in a collet.  Do you by any chance have a means of measuring (even crudely) how much torque it takes to make a 1/2" endmill slip in a collet using that setup?  I was able to do it by clamping a vise grip on a scrap endmill, and using a $5 hardware store "fish scale" to pull on the handle, then calculate the torque based on the fishscale reading and the length of the vise grip. That would be invaluable in helping me correctly calibrate my drawbar.

I'm going to read their patents and see what I can learn....

Regards,
Ray L.

The reason their system works with such low tension is they are using endmill holders which rely on a set screw that fits in the recess in the side of the endmill, unlike collets they dont rely on friction. The 600lbs of force hold the pull stud fingers up inside a collar. My milltronics uses a spring loaded fingers , marqaurt and a number of other companies have the "gripper" assemblies .


Here is the patent number for an interesting system. 5846037   here is a link to the patent office search page  http://patft.uspto.gov/netahtml/PTO/srchnum.htm  i attached one of the drawings from the patent below that shows their simple sytem of gripping the pullstud , they use balls wich have a tiny contact surface , some of the finger types have alot more bearing surface

 I dont know anybody doing any production work that uses collets over tool holders for the simple reason that you have to measure tool length everytime you change a tool with collets, and the obvious tool slipage problem . The tormach sytem utilizes a collet to hold the tool holders that overcome that one issue but as noted it has limitations and is for light duty use. Expecting to take a 1" depth of cut pass with a half inch endmill may be great as a sales tool but isnt practical in the shop .  

27

General Mach Discussion / Re: couple of things I have noticed with mach /g83 problem

« on: June 17, 2009, 10:10:47 PM »

that sounds like its above my pay grade , is there a link with description of how to do that

28

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 17, 2009, 10:03:14 PM »

I am running a full size bridgeport clone , 3hp , 10x54 and havent had any problems . I mostly work in aluminum though and rarely do any drilling with that machine so mine may not be a good comparison

The 6-800lb number for r-8 collet came from an articlle in HSM about various collets somewhere in the past 15 years , I have seen 600 lbs mentioned in a thread somewhere in the past also. I would guess your 2500+ lb number is probably more accurate . My manual list a torque on the drawbar of 15-20 lbs which calculates to over 3000lb of clamping force  for a 7/16x20 bolt

look forward to updates when your new parts arrive

29

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 17, 2009, 05:35:15 PM »

I was under the impression the tormach  holderfs/r8 setup only needed a few hundred pounds of upward pressure on the draw bar to be secure. we are running a washer stack that generates 800lbs on the mill and unlocking with a .2" stroke bimba 4" pancake cylinder , cylinder was less than $100 and I havent had a tool slip in the past couple of years of operation . I hadnt thought about the load being applied to the bearings when unlocking , I would imagine they are probably holding up OK but I am now wondering about the severe load on the ballscrew assembly on my quill . I like your idea of the locking mechanism to handle that load .

Please keep us posted on your progress. I am always fascinated by tool changers and related components.

30

Show"N"Tell ( Your Machines) / Re: What The World's Been Waiting For - Yet Another Power Drawbar Design

« on: June 17, 2009, 09:00:39 AM »

looks really neat .

Have you thought of just using a 4" bore pancake cylinder supported over the end of the factory drawbar?