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Saunders Power Drawbar kit on a PM935TV

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Alan H

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#1
I installed a Saunders Power Drawbar Kit on my PM935TV. I like the simplicity and it works well.

I discovered the kit a few weeks back and ordered one hoping to fit it to my mill. Saunders Machine sells the kit to fit a Bridgeport so I gambled that it would fit. I did have to drill an extra hole and slot two others in the mounting plate to get the right bolt circle but it was easy to do and it fits well.

The kit is built for a Harbor Freight wrench but after a trial, I ditched it. I am not a fan of that wrench. I replaced it with a Campbell Hausfeld which required a minimal amount of tweaking to fit. I have seen the internals of the air valve on both wrenches and the CH wrench is a step change in quality as compared to the HF offering.

I put 3/8” OD flexible tubing cantilevered off the back of the assembly for the compressed air supply.

To operate the drawbar you pull down on the lever to engage the socket onto the drawbar and then rotate the lever in the direction to tighten or reverse. The assembly works slick on the 12 mm posts with the linear bearings. Saunders has sized the springs quite well. I like this simple design which keeps everything including the air valve up top. It is compact, minimizes stuff hanging off my mill, and it all works via the simple lever.

By the way, the anodizing on the aluminum made me take a second look when I first saw it. For a moment I thought it was Delrin.

Bottom line, I think this is a very simple and economical solution. I am quite happy with it.

Saunders PDB installed.jpg side view.jpg Closeup1.jpg
 
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xplodee

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#2
You just made my day and gave me a project for the week. Ive been searching for an auto drawbar solution for my 935 and this is it.

Whats the part number on the CH wrench? Worth me stepping it up to a Chicago Pneumatic or is that over kill?

Tim
 

Alan H

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#3
Yes it is a simple solution that is not complicated and works.

Here is the Campbell Hausfeld wrench.

It has a working torque of 5 to 50 lbs. So it is not going to over tighten the drawbar.

I cannot give you too much advice on upgrading beyond the CH wrench. The CH works fine for me thus far and as I mentioned already, it was a step change in quality over the HF. If it goes south, I will move up from here and still do not have a lot invested.

I think all these wrenches of this configuration are relying on o-rings to seal the pivoting air supply and are prone to leakage. Once you have this one seated and working in the device, I think the rotation will be minimal and it will not be prone to leakage. However it is wise to have a metric o-ring assortment on hand just in case. I hate leaks!
 

Alan H

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#5
Okay, good. Please keep us posted with some photos of your install.
 

FOMOGO

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#6
Nice job on that Alan. The only thing I would add, would be an inline oiler for the gun, if you don't already have one. Cheers, Mike
 

Alan H

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#7
Thanks but I cannot claim the credit for this.

John Saunders at Saunders Machine is the gent who put this idea into play. I simply adapted it to the PM935TV mill. I used the mill yesterday and was again very happy with the way it works.

Of course this idea is not new but John's execution of it made it a bit different and simpler. He initially sold the pieces and parts as a kit (w/o the wrench) but then evolved it a bit more with improvements. The improved anodized version is the one I bought and adapted. Here is the Youtube of the John's first run at it.
Saunders Prototype
 

Stonebriar

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#8
I got mine installed today.

1.jpg 2.jpg

If you get one you need new longer mounting bolts. 6MM x 41mm

The ones John ships aren't metric since its for a Bridgeport.
 

xplodee

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#9
Mine is installed on my step-pulley PM935 model and working well. For the step-pulley model you will have to drill and tap two or three holes on top of the cast iron pulley cover, but it was pretty easy. You will also have to make three spacers.

I'll post some pics later tonight of mine. For less than $200 this was worth it. I didn't feel like spending $500-800 for the alternatives.
 

jocat54

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#10
I have seen several variations of power drawbar set ups and have always had this question in my head. On my mill r8 spindle I have to give the draw bar a slight tap to release the collet from the spindle, how would you be able to do that with the wrench in the way? Sorry if this is obvious.
 

Alan H

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#11
The impact wrench does it for you.
 

lpeedin

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#12
John is a good man and glad you were able to support him, but why in the world didn't you build your own? :)
 

Alan H

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#13
Option to build one from scratch if so desired is certainly a good option and it appears that many have done so. There are numerous go-bys out there, including John's. John even points a couple out in his video of the prototype.

For me it was simply the material cost and function were attractive plus it saved me some time. The materials are sized properly with outstanding appearance, delivered in one box, and ordered with one click.

Plus, as you point out, I like supporting good folks.
 

xplodee

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#14
A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big. Not enough Y axis travel to make use of the 5" full capacity. Better to save your money rather than getting something too big & most importantly the weight. I take my vise of the table quite often, a 6" is still light enough for me to be carried by hand but I'm glad I have a 5". I also have a 4" vise as well. I prefer the 5" though.

But those GMT 6" Premium vises are pretty nice. I'd love to have one but don't need one on my current mill. But if you plan on upgrading to a full size knee mill in the future than the 6" will be perfect.


Here's what the 5" looks like on my mill.



I couldn't even complete this cut without my bellows & DRO scale getting in the way. Not enough Y travel & the 5" vise is not even maxed out.



Here's what a 6" vise looks like on another PM45 (gt40's)
View attachment 253544
 

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Ironken

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#15
Hey guys.....how is Saunders fixing the vertical rods to the Al base plate? Press fit? Set screws?
 

xplodee

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#16
Mine is a press fit. Current bases are counterbored and the posts are screwed in
 

davidpbest

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#18
Before buying John's PDB, you might want to watch this starting at 6:35 in the video:

Watching that might help set your expectations. I know John, have a great deal of respect for him, own a few of his products. They are functional and good value, but not in the category of "refined" or "elegant". I have debated buying his PDB, and scrapping the Harbor Freight butterfly wrench for a better unit like Alan H did (see above). Instead I've decided to build my own version based on the CompEdgeX version implemented by Colin:
(part 1) and
(part 2). I like the compact nature of that design and the remote control lever that can be placed in a more convenient location. Obviously a lot more work and may not be your cup of tea, but check it out.
 

Ironken

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#19
I saw AvE's review as well. I was planning on building one. My mill isn't a B'port or clone. Easier to just make instead of modify.
 
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