# Power Drawbar For Rf-30?



## Ben Nevis (Jan 20, 2016)

Anybody have an idea how to implement something like this on an RF-30?


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## TomS (Jan 20, 2016)

Ben Nevis said:


> Anybody have an idea how to implement something like this on an RF-30?



Anything is possible.  At a minimum you will need to modify the belt guard.  Any chance you can get drawings of the draw bar and holder/collet mechanism?  That would help a lot.  

I have a Ultron Snap Change (snapchange.com) system on my PM-932 square column mill that appears to be similar.  BTW - it works great.  Also have an Enco RF30 clone that I would like to convert to a quick change system.  I will be following this thread with interest.

Tom S.


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## Ben Nevis (Jan 20, 2016)

I came up with a couple of ideas, thought I'd run them up  the flagpole to see if anyone salutes.(That's an expression I haven't heard in a long time...)

The first is to mount two pieces of 1/4"x1" steel (or aluminum) to the spindle nut, with a cross piece of 1/2"x1" for the spindle to push against.
They would be rotating with the spindle, not sure how well that would be at 2500 rpm, though....

It would require milling two flats on the nut (they are slightly tapered) and tapping two holes in each side. After seeing a thread about someone trying to find a replacement nut, I am a bit reluctant to try it. Also, my mill would be out of commission when I take off the nut. Now that I think about it, I have a milling attachment for the lathe, so I could do it that way.

I would have to make the hole in the belt cover somewhat bigger, but that's no problem.

The second idea would be to mount a piece of angle iron on each side of the mill head, just below the belt cover, to provide support to the uprights, and a cross piece over the spindle. Would need to make them a bit bigger because of the longer span.
Would  require cutting a large slot in the belt cover, again no big deal, just might look a bit crappy having it sticking out of the top.

Thought and comments or better ideas welcome.


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## TomS (Jan 20, 2016)

Ben Nevis said:


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I looked at the Hoss Machine website and have a better idea of how this system works.  After viewing the two videos it looks like he's using a 3/4" R8 collet and a "tensioned" drawbar utilizing belleville spring washers.  The tool holders are straight shank style like the Tormach TTS holders.  The overhead bar provides a means to compress the belleville springs thus releasing the collet tension and allowing the tool holder to be released.  OK, enough of my jibber jabber.

Adding material to the drawbar IMHO is not a good idea.  The more spinning mass hanging on the end of the drawbar the more likely you'll have an imbalance issue, and at 2500 rpm it could get ugly.   Your second idea is a better option.  Whatever path you take you will have to modify your belt cover.  Keep us posted on your progress.

Tom S.


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## davidh (Jan 21, 2016)

after serious thought i decided to just use a dewalt 18V battery powered impacting tool with a fixed socket attached.  it sits upright on its battery on top of the plastic guard so its always handy.  and it has not tumbled off in a couple years now.


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## Ben Nevis (Jan 27, 2016)

Tom, You have described the setup exactly.

David, I have been using a cordless impact wrench (Bosch) for some time now, but it is still a pain when the collet doesn't eject on it's own. You have to set it down, find something to smack it, and then finish unscrewing the drawbolt.

Anyway, I decided to go with the second idea I posted . I had a piece of 4"x4"x3/8" angle iron, so I used that to make the brackets that mount under the belt cover, fastened with four 1/4-20 bolts. The uprights are 1/2-13 threaded rods, 11" long.  The crosspiece is 1"x1" HRS, one end drilled 1/2", the other end notched to allow it to pivot out of the way if needed. I used nylon locking nuts to avoid having it vibrate loose, and only requires a small turn of the top nuts to release it.

I used a spring on the drill depth stop to keep the quill from returning fully, to avoid the drawbar from hitting the crosspiece, except when you push the spindle up fully to release the tool.

I drilled two holes in the cover for the threaded rods, don't look too closely at the pics, I didn't measure quite right, and had to hack up the holes to get them to fit... OOPS!

This won't allow the cover to be opened without taking the rods out first. I have a VFD, so it isn't necessary to remove the cover very often. Also, the one rod is too close to the number 4 pulley to use the belt on that position. Again, with the VFD, I don't foresee ever needing it.

If you don't have a VFD, you would need to cut a big slot in the cover, and mount the rod a bit further away.

I had to make a new drawbar 1 1/2" longer than the original to account for the Belleville washers (I used 6 in series, rated for about 650 lbs) and a 1" spacer to allow the spindle to travel fully. The washers are just slightly bigger than the spline in the pulley, which limited the travel to about 4" without the spacer.

It works just like in the video, a push on the handle, and the tool pops out. Push on the handle again, and insert the next tool.


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## TomS (Jan 27, 2016)

Ben Nevis said:


> Tom, You have described the setup exactly.
> 
> David, I have been using a cordless impact wrench (Bosch) for some time now, but it is still a pain when the collet doesn't eject on it's own. You have to set it down, find something to smack it, and then finish unscrewing the drawbolt.
> 
> ...



Are you using the TTS tool holders?  Or are you making them yourself?

BTW - nice job!

Tom S.


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## Kennlindeman (Jan 28, 2016)

Love what you guys are doing but you lost me with what type off holder is being used. A R8 has the key and need to be turned out?


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## Ben Nevis (Jan 28, 2016)

The Tormach TTS tool holders have a 3/4" straight shank that mounts in an R8 collet. The Belleville washers provide the upward pressure to draw the collet into the spindle taper. Pushing the quill up against the crosspiece releases the pressure, allowing the tool holder to be removed, same as if the drawbolt was unscrewed. The R8 collet remains in the spindle.

So far, I only have 1 ER20 collet holder and a set of collets, have some end mill holders, drill chuck arbor, etc on order, should be here Fri.


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## Kennlindeman (Feb 2, 2016)

What are the sizes of the washers you used. Were they med or Heavy duty?


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## Ben Nevis (Feb 2, 2016)

The Belleville washers I used are 12.2 mm ID, 25 mm OD, 2910 newtons,(654 lbs)

Made by Associated Spring Raymond, BD025-150

I bought  package of 10 for about 13.00 usd last year from Amazon, seems as if they have raised the price to about 30.00 usd now.


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## Ben Nevis (Feb 2, 2016)

The spring I used on the quill depth stop wasn't quite right for the job. It turns out that 4 rubber garden hose washers are perfect to keep the drawbar from hitting the crosspiece, but are easily compressed when needed to release the tool holder.


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## Kennlindeman (Feb 3, 2016)

Thanks for the feedback Ben. My little mill/drill which is mainly used for drilling as I have a bigger mill is going the get a upgrade. I will be doing a quick change setup like your's, I have ordered 3 digital scale similar to your's and a gas spring to help take up the play with the down spindle


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## GreatOldOne (Mar 2, 2016)

I've got a captive drawbar on my RF 25, and use a ryobi cordless impact drill. It ejects the MT3 collets and tooling I use no problem at all. 

I followed the same format as explained by cuppa joe, here:


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## Ben Nevis (Mar 3, 2016)

I considered the captive drawbar, looks like a good idea, but chose to go with the Belleville washers instead.

The RF30 has a 1/2" hole in the spindle, and the drawbar is 7/16" dia. You would need to bore the spindle 17/32" an inch or so deep. I don't have a drill bit that size, and when I envisioned myself standing on a stepstool trying to drill it by hand, and then tapping 5/8-11,( not gonna remove the quill and mount in the lathe to do properly) I quickly lost interest in that idea. Would also have to turn down part of the drawbar to 3/8" to fit through the bushing.

I wound up having to make a whole new drawbar anyway, so maybe it wouldn't have been so bad after all....

I have my mill mounted a bit higher than usual to save my back, so when the head is in the higher position it is a good stretch to reach the drawbar, so I wanted to avoid having to unscrew it altogether.

BTW, nice job on the "Cuppa Joe" mod, I have a 20 mm shaft and linear bearings waiting to do that to mine eventually.


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