Lathemaster/RF45 belt drive conversion(hopefully)

[pete from TN]

Believe me when I first turned the pot to max freq I was nervous about it. I made all of the rotating mass here on my lathe and it is a considerable amount of metal spinning there. The coupler that I am using to hold the spindle pulley is pretty heavy duty cast iron unit and it now sits in a pair of bearings with keeper rings on top and bottom so I do not think it is going anywhere. The top pulley is aluminum as you can see and it is machined with a matching taper to the cast iron bit it drives. Then there is a large fine thread locknut to hold it in place. The pulley on the motor is actually captured inside the standoff little cage that holds the motor off and if it were to come loose somehow it would just destroy itself until the motor spun down to a stop. The belt is very short and also is kinda captured by the standoffs should it fail the only way it is coming is possibly forward toward the user(ME!!). I am planning on building a pneumatic drawbar assembly that will have a shroud that is the mounting plate that will make up the frontal protection and should be more than enough to keep me safe. Worst case scenario the spindle pulley lets go and becomes a flying saucer it is pretty light and smooth so no labotomy I am afraid altho it probably would leave a nasty bruise... I was actually running the spindle yesterday after work trying to break the new bearings in and started hearing a slight vibratory noise and took it apart to find that I will be replacing the spindle bearings sooner rather than later. If you read thru the posts I had noticed a tight spot in the bearings while playing with the mock up so no surprise there. This tight spot and the new higher speeds was a certain death to the bearings that were in there for the last eight plus years that I have abused this little machine.

So over the Memorial day holiday I am gonna fine tune the belt drive and try to make it over to the bearing house to see my pal there to set me up with some new higher quality higher speed bearings for this thing. The motor and vector drive are nearly silent except for the little fan that it has inside that makes some noise.... I may actually try to tear into the bearings tonight and check them for lube, clean them and reinstall them to see if there is some crud that got in there during the teardown. Gotta get some of that cool grease Bob recommended....

My timing belts for the xyz axes should be here tomorrow from the tracking at ups.com so I will have that to play with over the weekend too... This machine should be fully functional very soon... CANNOT WAIT!!!!

Peace

[rbond]

Hey Pete ,how are you making out with the belt drive system? Is there enough power
and torque at all the speeds you are using?

Rick

[pete from TN]

Standby for the response as I just recently got the cnc part of this thing working and now I need to get the machine all buttoned up and hook up the Teco sensorless vector drive to the Cnc4Pc breakout C11g board and I will be able to make a trial run...peace

[pete from TN]

I just thought I would resurrect this posting since I have finished the cnc mill basically and the belt drive has quite a few hours of run time on it. Tonight I machined a little simple manifold for the one shot oiler back half of the system and I was doing a peck drill cycle with a 7/16" endmill to prep for the 1/4" npt threaded brass oil port connectors. The machine was working beautiful and despite me forgetting to spray some lube on the cut while I was shooting the video I think you can see that the belt drive is capable and working well. I think I will also post another video of the machine doing a pocket cut of some kind to show it is quiet and smooth, because luckily it is!!

ANyways here is a link to the video...peace


"http://www.youtube.com/watch?v=K7wCuLGimJg"]YouTube - Lathemaster cnc mill peck drilling cycle....

[Teyber12]

wow that thing moves amazingly!

[pete from TN]

I am amazed at how well it is working, especially since I built it!! The spindle belt drive is working real well all the way up to 6k rpm. I am right now trying to upload another video I made of the machine doing a rectangular pocket. Once it is on youtube I will put it here if you guys wanna see it... peace

[pete from TN]

Here is another short video of the machine running a Mach 3 rectangular pocket test.. whaddya thinK??? peace

"http://www.youtube.com/watch?v=w3AdmYgjtiw"]YouTube - Lathemaster cnc mill retrofit rectangular pocket test run


Hope you guys like it...

[SCzEngrgGroup]

Pete,

Lookin' good! (well, from the little I can make out in that horribly over-compressed YouTube clip....).

Regards,
Ray L.

[pete from TN]

Actually that is a cell phone video as I still cannot seem to find the nice camera, it is somewhere around the house here. The machine is really starting to get used to me or the other way around I think.... I am gonna start building the enclosure for it right after I finish the cabinet job I am working on.... SHould be nice with the enclosure, I have some neat ideas for it I think....


Glad you like what you see and I am gonna post another video or two of the machine with the better camera once I get the machine enclosed and liquid cooled...peace

[Bird_E]

Pete,
Your machine looks great. I'm real intrested in your belt drive! I have already started my belt conversion after I saw your thread.

Can you tell me what diameters your pulleys are? Have you tried the low speed yet? do you think it has enough torque? what about belt slip do you get any? Also, are you still running V-belts or did you switch to timing belts and pulleys?

Sorry for all the questions!!!
Thanks!
Bob

[pete from TN]

Glad to hear that I am not the only one with belt drive aspirations. As you can see from the videos that extra Rpm goes a long way.... So far I have not been able to slip the belt. The belt is a Vee belt and I machined the pulleys to fit them nice. I did not use timing belts mostly due to cost but also because I wanted two speeds and the spindle pulley is two tier and is machine to fit a taper on the quill spline drive coupling. That taper made getting a suitable pullley difficult. I am sure it could be done but I looked at the Tormach machine and my Knee mill as well as my Last round column mill, all have vee belt drive and all worked fine. The video is showing the high speed pulley set in use and I have used the low speed. Of course the slower speed pulley is more torquey and so far I have not had ANY issues with torque. In fact the machine seems much more powerful and capable now with the belt drive. It is also MUCH MUCH quieter.... This is a welcome thing because the gear head I had was pretty loud at max speed which was a lowly 1700 rpm.... Nothing like cutting aluminum at 5500rpm!!

I would not mind sharing with you the pulley sizes I used as long as you do not try to sell the design... It is in the public domain because I wanted it to be so others that have helped me with information can also benefit. I will also add that the sizes I used were to attain a set realm of speeds that I wished to have. The low speed was a large part of it for me. I wanted to be able to spin larger silver and demming drill bits as well as large face mills within the capacity of the machine. Therefore with the sizes I worked up I am getting a reasonably slow low speed of 140 rpm up to around 1100 rpm in the low speed pulley set. Then I am getting around 900 rpm up to around 5900 or so rpm depending on how high a freq I am willing to dial up. I do not like to run the Vector drive at more than 120 hz or so even tho it will go higher than that. The lowest freq I am willing to go is around 20hz....and that is mostly due to advice I have gotten from others that have similar systems. The belt drive is just too easy to do and the advantages it brings are obvious. That coupled with the power drawbar I am gonna build and this spindle will be just about where I want it.

Please post some pics of your belt drive setup, I am always anxious to see others ideas... peace

[Marmot_Militia]

I've spent some time talking with Pete and have been following his conversion since the get-go.

I had decided I wanted to do this to my LM mill as well. I figured since I have the motor, VSD, and switches from my old Smithy it shouldn't be a problem....or could it.

My motor is 2800rpm!!!! ugh, gearing it down to around 100rpm will not be possible with a single pulley reduction. I simply don't have the room between the spindle and motor. Then I find the Dart 125D lacking in it's ability to reverse the motor without an external relay as well as other things that make it a bad choice.

So I'm back looking at my options. I'm leaning more towards a VFD and 3ph motor since I have to buy new anyway.

I am running Mach3, PMDX-131 BOB. I will be getting the PMDX-106 Spindle control daughter board and their slotted optical sensor. Would anyone be willing to recommend a VFD that works well with Mach?

I'll post pictures as progress ensues.

Regards,
MM

[SCzEngrgGroup]

I've spent some time talking with Pete and have been following his conversion since the get-go.

I had decided I wanted to do this to my LM mill as well. I figured since I have the motor, VSD, and switches from my old Smithy it shouldn't be a problem....or could it.

My motor is 2800rpm!!!! ugh, gearing it down to around 100rpm will not be possible with a single pulley reduction. I simply don't have the room between the spindle and motor. Then I find the Dart 125D lacking in it's ability to reverse the motor without an external relay as well as other things that make it a bad choice.

So I'm back looking at my options. I'm leaning more towards a VFD and 3ph motor since I have to buy new anyway.

I am running Mach3, PMDX-131 BOB. I will be getting the PMDX-106 Spindle control daughter board and their slotted optical sensor. Would anyone be willing to recommend a VFD that works well with Mach?

I'll post pictures as progress ensues.

Regards,
MM

For small motors (3HP and below) the Teco FM50 is hard to beat. It's under $200, very simple to setup, and works great.

http://www.factorymation.com/s.nl/sc...FR5HagodHgcrbQ

Regards,
Ray L.

[pete from TN]

Hey marmot!! nice to see you on here. Sorry to hear that your plan to do this is not working out but I gotta say that I am having pretty good luck with mine so far and I am also using a Teco sensorless vector drive unit and 3hp 56c frame motor. The Board I am using is the CNC4pc c11g board. The board has been working very well so far despite my initial confusion about the proper wiring( I dunno what the hell I am doing!!)... Anyways the nice thing is that the board has on it a 0-10v variable freq driver to control the VFD>. My motor is a 1720 rpm motor and I am able to get it down to around 140 rpm. The freq range I have been comfortable using is actually wider than I at first thought. I was running a 1/2 inch drill bit yesterday in a TTS holder and had the spindle in the high rpm pulley set. I was able to spin it down to around 900 rpm for several peck drill cycles thru 3/4 inch aluminum and was constantly checking the motor for heat or any signs of stress and found that it never even got warm... I will have to rerun the program and open the control box to see what the actual freq I was running at was but I am sure it was pretty low... What I am saying is that you might be surprised at the range of speeds the vector drive will give you. I got mine for around $200.00 and it seems to have been money well spent...

As I told you in our e-mail conversations I would be willing to help you with yours if you need it. Have you seen the videos I posted recently of the machine running? Nothing like 6K rpm thru aluminum.... I am trying to source a quality three flute aluminum high helix endmill that is reasonably priced right now so I can do a proper video of the machines capabilities. I did have a small drawback tho, I was running some code yesterday and found that I have developed some backlash in the Y axis. I am trying to fiqure out what it is right now but it is probably something I did not tighten down or other....peace

[Marmot_Militia]

Hey Pete,
Yes, I have seen your videos, very cool. I can't wait to have a quiet spindle. The gears in my head (!) are noisy and have a lot of backlash.

I appreciate your offer to help.

As far a endmills, try www.maritool.com I use their 3 flute carbide 38 deg helix in .125" dia for my RZ spindle...talk about munching metal! They are cheap, and made in USA.

Himy,
thanks for the link. Looks good to me...now onto a motor.

Any preferences? Need a C-frame (face) mount.

Regards,
Jim

[SCzEngrgGroup]

http://www.cnctoybox.com/ is a great source for very nice, inexpensive 3-flute carbide endmills.

Regards,
Ray L.

[pete from TN]

What is an RZ spindle? I like the looks of the three flute carbides on that maritool site but I was kinda hoping for a higher helix. The more expensive aluminum bits seem to have a higher twist and the local pro machine shop I frequent gave me a recommendation on one like that from Msc. It is a little expensive but not too bad. I may just try one of each....peace

[Marmot_Militia]

Pete,
I have no trouble clearing chips with the 38 deg. I tried the Accupro from MSC and got a little bit of edge buildup even with air and mist.

I just don't think they are worth the 4x the price of the uncoated from Maritool.

Give them a try. Shipping will be much cheaper too.

Regards,
MM

[pete from TN]

I think that they will probably be fine and as you said they are cheaper. I was just out there doing some practice runs with the machine and I am kinda liking the two flute with the 5k spindle rpm but what is the standard endmill helix rate anyway? Thanks for the info. ya been shootin' any airguns lately?? I was hoping to make it to the Nationals but this economy has been kickin my butt lately with the sidework in my cabinet shop slowing. May not be able to make it unless something gives somewhere. Peace

[Marmot_Militia]

Pete,
My shooting has slowed down considerably. Won't be at the Nats either.

Noah and I were busting some clay pigeons earlier with his 2240.

I've been feeding around 15ipm. I was making resin cups for my wife's jewelry and was down to my last end mill so didn't want to push it. I just got some more and will see how fast I can push them soon.

Regards,
MM