[Mad Welder]

This is a great link to a decent video of Chris from the geek group applying epoxy. I'm planning the same when my workshop is finished.


cheers,
Ian

Thanks for the link Ian ....pretty good information there too....

[Mad Welder]

O

[Mad Welder]

Spent a bit too long today learning how to draw a timing belt pulley.......and machining one manually may be a wee bit too difficult for my capabilities at present....I haven't written it off just yet, but in case I make a bags of machining them.... I ordered timing pulleys from SDP today.........https://sdp-si.com/eStore/

[Starleper1]

Easiest way to draw a timing pulley and/or gear.

Gearotic Motion

[Mad Welder]

Easiest way to draw a timing pulley and/or gear.

Gearotic Motion

Good link cheers

Came across this link too guys another pretty good one to bookmark for stepper motor research explanation and stepper wiring setups Basics|Basic Information|OSM - Optimal Stepping Motor Supplier

[Mad Welder]

Almost finished my temporary 4th axis using my rotary table.......I had intended to build from scratch my 4th axis as the rotary table would have a little bit too much backlash using the worm gear I figured.......but I really would like to try and machine a timing pulley so for now I'm going use the rotary table......I'll wire it tomorrow if I get time........

[Mad Welder]

Wired the A axis today and in ‘hindsight or oversight’ if I had factored in the tightening of the rotary table worm gear to reduce backlash I wouldn’t have fitted a direct drive coupling from the stepper as now I have a minute off center stepper it’s only minimal but there still all the same….. so as I don’t have a flexible bellows coupling I made a new base plate out of Delron to allow for a little flexing……and that’s worked…..it’s still only temporary as I intend to make my fourth axis from scratch but with tightening the worm gear I have almost eliminated backlash from the A axis…….I ran a simple little GCode and I’m not sure if it would be the best way to check the A axis for backlash or not so I’d appreciate any suggestions here on the most accurate way to test the rotary axis…….. and on a lighter note too guy’s your USPS is flippin brilliant got my SDP delivery today yeppee more toys and goodies to play with, and I also made a mistake when ordering my timing belts too……oops……I inputted the incorrect dimensions so the belts are a wee bit too small, so I’ll order more and see if I can make do with the delivered ones, oh and I'm using a DTI with 0.01mm (o.oo3") increments in the video....



DIY CNC Fourth Axis.mp4 - YouTube

[Starleper1]

Do yourself a favor and check out MSM. After using it for awhile now, I can't bear to look at the standard 1024 screen set.

Just a suggestion...

[Mad Welder]

I was pretty happy boring the SDP pulleys to accept the motor shaft and the Spindle Drawbar retaining collar dimensions until I mounted the pulleys on the spindle and realised that the threaded drawbar collar is not concentric or really I should say that when rotated it’s run out it terrible there’s a couple of millimeters of discrepancy between the top end and the lower threaded end, however when rotated and clocked in the lathe it’s pretty bang on……I did a bit of YouTube searching and found that this seems to be a common occurrence so I’ll have to have a read through different threads to see what other lads have used to fix their pulleys to their spindles…….I was kinda hoping just to leave the stock gear combination shaft (Optimum pt. no. 0320255) as is because I already upgraded my spindle bearings but I may have to rethink my pulley setup……..

I turned down my previous pulley blanks to accept a V-Belt and I’m not sure if this is frowned upon by machinists but the only tool I had available today was my parting tool so if anyone else is following in my footsteps providing your parting tool is as rigid as mine and when used with caution (low feed rates) it can do the job just fine…..

and I included a few seconds of video showing the poor run out using the stock retaining collar…..

20120809 164231 - YouTube

[aarggh]

You must be pretty damn stoked with that effort! Great job! When time permits (Ha!) I'm planning the same, but i'm also looking at another one as a second rotary indexing axis instead of cnc control, (dial in how many divisions per 360 deg rotation). There's some great free code projects around for that. I think they'll compliment each other real well and fulfill many roles.

cheers,
Ian

[Mad Welder]

I'm not sure why these photos didn't get uploaded with my last post....but for anyone who may not have turned down a V-Belt pulley before like me as this was my first here's a suggestion........

[hoss2006]

I

I turned down my previous pulley blanks to accept a V-Belt and I’m not sure if this is frowned upon by machinists but the only tool I had available today was my parting tool so if anyone else is following in my footsteps providing your parting tool is as rigid as mine and when used with caution (low feed rates) it can do the job just fine…..

Nice work.
I used the same tool when turning my 3L v-belt pulleys and it does a great job.
Made my own HSS cutter for smaller 2L pulleys only cause my parting tool was too big.
Whatever gets the job done for you.
Hoss

[Mad Welder]

Thanks for the kind words Hoss and aarggh !

I measured the run out of the Drawbar collar and I got a discrepancy of 0.3mm (0.011")


[ame=http://www.youtube.com/watch?v=1mu1VttY7P8&feature=plcp]0.3mm run out.mp4 - YouTube[/ame]

and to reassure me I measured the run out of my spindle again and I got 0.01mm (0.004”), which for a hobby CNC Mill is fine, I mean lets face it I’m not building a space ship… (yet ha ha! )…… and this is with an upgraded tapered roller bearing after my past costly learning curve of, when I crashed my machine and broke the MT2 spindle…..and so when I finally decide on what spindle conversion to use or build I then will also add Angular Contact bearings on the spindle where I may be able to add additional tensioning on the bearings and then I may also reduce the 0.01mm run out a bit more…but time will tell….and this is the video of the spindle run out measurement

[ame=http://www.youtube.com/watch?v=-OKXXmwROAY&feature=plcp]0.01mm Spindle runout BF20.mp4 - YouTube[/ame]

[hoss2006]

Not fully sure how your spindle is designed but imagine it's fairly similar to the 0704.
The part you indicated is the unsupported end of the spindle and can be pushed back and forth with fingers
so it doesn't make a good pulley mount.
The part arrowed in the pic, is it supported by the bearings in the head? and hows it's runout?
I make a cbore in my spindle pulley to seat on a similar bearing supported part on the 0704 (the gear assembly) which keeps it true to the spindle then setscrews to grab the upper end of the spindle without the retaining cup to transfer power (non quill version).
Just food for thought.
Hoss

[Mad Welder]

Thanks again Hoss, and rather than asking I had to Google ‘cbore’ ha…

And yup you’re bang on…. the runout on the gear assembly is less than 0.01mm
:cheers:
[ame=http://www.youtube.com/watch?v=SwuKTHls3zU&feature=plcp]BF20 Gear Assembly Runout under 0.01mm.mp4 - YouTube[/ame]

[Mad Welder]

I had no stock larger than 40mm OD so I made a collar to fit inside the collar that Hoss suggested to attach the pulleys too and it worked a treat I ran out of camera battery before I had the belt on and running but you'll understand from the attached pics........and I had the head stripped before I remembered to take a final pic.....

[Mad Welder]

This is my fourth attempt to upload these pics, and I'm now typing from my PC been using my phone........... my wife laughs and says "me and electronics don't go together"(flame2)

So again it's just an alternative route to mounting the pulleys for a belt drive conversion

[Mad Welder]

Now that I started the belt drive conversion and I machined a few simple projects…. geez is it quieter than the noisy stock motor with the gears…….but I’ve decided to go the full hog and change to an R8 spindle and upgrade to the AC bearings…the reason to move on is I’d like to attempt a version of PDB I have in mind and also it appears to me that the standard for TTS and similar manufacturers tool holders is ¾” and my little MT2 collets only go to 12mm, now I Know I can get an ER32 collet holder from Optimum to fit the MT2 taper spindle but I figured with the standard R8 my tool holder range would allow for a far broader amount of tooling and can also be purchased from various suppliers as opposed to only purchasing one ER model, also Hoss on his projects page has turned down his own tool holders and Epoxied collars to his version and they look very similar to the original TTS holders so this may be an even cheaper route to follow too…and I would like to follow in many of your footsteps with the full automatic tool changer in time……
so I’d appreciate any input and advice with this project and has any one converted an MT2 to R8 spindle? is it just a straight forward replace of one spindle for the other? what R8 spindle supplier would you suggest?

[Mad Welder]

Ok so I'm leaning towards the ISO 30 Tapered spindle as opposed to converting to R8….I’d like to hear for and or against and I’ll need some help here guys…..after spending a lot of research time on the internet it appears that while the R8 has been in existence for a millennium and has an excellent record and has history to prove it, there are a few advantages for choosing the ISO 30 over the Bridgeport R8…..and unfortunately as I have no experience with either tapers, so I for one cannot argue whether one is more beneficial to me than the other……but apparently after comparing like for like in internet searches the final conclusion is that as the ISO taper has a larger surface contact with the spindle taper and apparently this allows for a stiffer and stronger axial side load force capability when milling…..but of course again this also depends on whether the host machine has stiff ways, linear guides etc etc., also reading suggests that even though Tormach TTS has produced repeated correct tool length measurements it appears that the ISO range has been more reliable for repeated tool length accuracy as opposed to the R8 spindle….but again this is only my understanding from reading the literature…….. But one thing I’m a bit confused of and would appreciate some help is in the bearing selection….. Should two single matched pair of Angular Contact bearings be fitted back to back at the lower end of the spindle and one single matched AC bearing fitted at the upper end of the spindle to support the side force of the pulley belt adjustment??......and what is the correct taper degree of the AC bearings??.....or what is the best configuration setup of AC bearings??...

The first thing I need to do is to extend my quill so as to accept the larger lower spindle dimensions……..

[SCzEngrgGroup]

If you intend to add an ATC, and TTS is not "heavy duty" enough (meaning your spindle is in excess of about 2HP) then ISO30 is the way to go. If not, it really has no advantage over R8+TTS, and tool-holders are considerably more expensive, and can be difficult to come by. For any benchtop machine, TTS should be more than adequate, given the very limited rigidity of the machines.

A/C bearings are completely unnecessary at the top of a spindle, as the load is entirely radial.