Part 13 - (Removing the draw bar)
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- Опубликовано: 14 окт 2024
- Part 13 of the Fadal VMC 4020 reconditioning series.
Removing the draw bar.
If you would like to use my 3D printed draw bar removing tool, you can follow this link : a360.co/2IjsPaQ
Blaise, Your machine has an early non locking drawbar assembly. I'm surprised to see that, cause I thought we had to upgrade existing installs like a factory recall, my mind slipping I guess. I retrofitted quite a few assemblies to the locking drawbars. Lockers would have 4 additional ball bearings under a X looking part that got secured under the drawbar keepers. Please note the locking versus non locking drawbars were different in hardness and where retainer ring grooves are, along with belville spring quantity and orientation. Some times shims were utilized at the retainer end to achieve specified drawbar retaining pressures from the spring pack, to much pressure and the tool unlocking air cylinder would struggle to release the tool. To little pressure resulted in usually bad finish problems in milling operations. The pressure was checked with what we called a drawbar dyanometer. Lastly it was a messy job due to the copious amounts of copperkote that the new springs were packaged in. Did you get the "cup" that encapsulates around the tool retention end that is up in the spindle taper? It is a hheat treated collar that is retained in the spindle by 2 balls, sometimes those were buggers to get out, use some shim stock to slide between the spindle and cup to have the balls come towards the spindle center, air gun at same time helps to. Take care, Jeff
Hi Jeff! The knowledge you have of this machine is impressive!!! You are absolutely right, it!s the non locking draw bar. This is the one thing this machine was doing right! I don’t remember never having any problems with toll changing. Fingers crossed. I did not remove the cup. But I love the shim stock trick! Many a right size magnet could work in pulling the balls towards the middle as well?
@@BlaiseBarrette Yes Blaise, as the old adage "there's more than one way to skin a cat". With the components in years of service, sometimes the cup would get some damage at the retaining holes to release the balls with a magnet and air, thus the shim stock trick. Please use care doing this! I can recall rushing the job (time is of the essance) and getting the shim stock stuck also. After much failed attempts, it was just simpler to pull the spindle out and die grind the cup in 2. I recall customers that were doing a lot of heavy side milling would have a tendancy of basically sucking the tool out of the spindle and having a wavy bottom finish along with chatter and ultimately spindle and toolholder damage over time. The locking drawbar had a 4 ball locking mechanism that worked very similar as the balls do on the retention knob but expand outward and seat on top of the spindle creating a positive stop. These had to be adjusted using shims at times . Look forward to your next video. Are you going to use single phase? Fadal had single phase available and it consisted of a different main transformer, varistor board, and one more change , relays for spindle forward/reverse I think. Additionally you mentioned 7500 RPM, you have a 10,000 RPM set up as I see it. Is your spindle a air/oil lubed with the old Bijur spindle luber and a small tank with a graymills pump and antifreeze? If so it's a 10,000 RPM.
I never would have thought of using a plastic part! What type plastic? PLA?
Yup! 100% infill. 🤪
Ah the dreaded drawbar... lol... Many changes were made over the years hence the many different number of Bellville washers. Originally the Belvilles were just standard... but Fadal started to Shot Peen them to close the micro cracks because of breakage... not sure the after market parts guys Shot Peen now. I believe your Spindle is THE Original from the factory spindle. A couple of reasons your machine is 1989 and the spindle 1 does not have the Locking Drawbar which was Patented in 1990 (applied) by Dave patent # 5022278 . You actually have the version Spindle that was greatly strengthened by the much more meat in the nose of the spindle. Basically the Diameter was increased not the Housing. So if you look at the keyed or nose of your spindle there is more meat beyond the Keys. Originally the spindles diameter was the same as the Keys. Fadal threw out ALOT of spindle because of this change. The problem was that looking at the spindle (the spindle was drawn designed by Pencil on a drafting table No Cad at the time No 3D to look at a sliced view) anyways it was found that where the taper Cat40 and spindle it was very very thin wall at the thiniest point if i remember something like .100 to close for comfort.
The other reason is that the spindle looks way too polished the nose of housing and I knew some of the Assemblers loved to show off their sanding and buffing skills and add that clear lacquered finish. They use to spend and hour sanding to make it super smooth.
Anyways if you wanted you could add the Locking drawbar with the correct drawbar and parts. But not super necessary.
You can go to the antiquated USPTO website and look up the patent man there website needs to be seriously updated its embarrassing
I am very impressed by the amount of knowledge you have on these machines!
I bought this one from my boss. I have been working with it for about three years before I acquired it and the tool changer has been working flawlessly so I won’t replace the drawbar for now. Once I know everything works, I’ll will be more incline in investing for new parts. My firs investment will definitely be replacing both of the spindle pulleys. They are in very bad shape! I currently have the 6 V belt pulleys. I would upgrade to the pozi kit.