# Power Draw Bar Install on PM TS Style Knee mill



## Kamloopsendo (Dec 7, 2019)

I recently purchased a Power Draw Bar for my PM 949 mill which is a TS style with a cam on top to engage and disengage the direct drive when changing speed ranges.  I had talked to Matt at QMT via E-mail awhile back and he sold and recommended purchase of the Maxi Torque-Rite unit which I ultimately purchased from KBC not Matt as I'm in Canada and getting the unit from Matt is a significant amount more hassle and the price was the same from our Local KBC store.  At any rate the unit should work but I've no real idea how to attach the power head.

Problem I have is that everything I see describes mounting it on a TV style machine.  With the TS style head it simply ain't as simple.  Has anyone done this and if so what are the tricks. I'm guessing I need to turn (or purchase?) a spacer to go from the top of the bearing housing to the base of the Power Draw bar unit.  Even so not sure exactly where attach as I don't think drilling and attaching to the lock nut is a good idea as the ongoing reversing torque from the power head will likely loosen the bearing lock nut with time and the ring that the nut threads into is pretty marginal in radial thickness to attach to.

Any one who's been thru this I'd appreciate hearing how you did it.


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## davidpbest (Dec 7, 2019)

I'm guessing you bought the generic Maxi Torque-rite rather than a version specific to the step pulley machine.   Several version are offered by the manufacturer:







I bought my Maxi Torque-rite from the manufacturers rep.   His first question was "Do you have a step pulley machine, or the one with variable speed".   The step pulley version comes with stand-off studs that position the mounting platform for the unit above the ring on top of the head where the spindle brake and Hi/Low selector levers are located.   Proper centering and clocking of the standoffs are both important when positioning for the mounting bolts.











The second question the rep asked was about the specifics dimensions for my mill as shown in this attached drawing (your machine may be different - this is for the PM935).   He asked for these dimensions so that the drawbar they supply was made to fit my machine specifically.   It had a specific head length that was longer than the factory-supplied drawbar, and the overall length was increased by almost 2-inches. 






You can probably make your own stand-offs to mount the generic version of the PDB above the ring as shown in the photos above.

The issue you are more likely going to be troubled by is the drawbar itself.   With the pneumatic actuator system positioned further upward, you are going to need a longer drawbar with a head design that brings the top of the splined head to the proper height.   You could potentially add a bushing to the shaft of the drawbar to raise the height, but then the drawbar will probably be too short to reach the tooling in the spindle.

You should be able to order a properly sized drawbar through the rep:   https://www.maxitorqueritedrawbar.com/drawbar_models.php

Hope this helps.


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## Kamloopsendo (Dec 7, 2019)

David:  You never fail to help!!  I'm headed out for a bit but will have a better look tomorrow.   The drawbar I have will be short, I'd kinda figured that but I really thought the power head had to be mounted to the bearing housing so that it moved up and down with the bearing housing when shifting between low and high range.  That does simplify things a bit.  I'm going to ***** to KBC as there should be some responsibility on their part to sell the appropriate unit (I hope this'll cover the draw bar cost at least!!).
Mark Jacobs says you do a fair bit of work with 304SS so I may be asking about that too as I've found it quite the challenge to deal with!

Thanks much once again for the help.
Alex


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## Kamloopsendo (Dec 7, 2019)

Just ran out to the shop and realized the draw bar does not move with the cam action so of course a fixed stand-off from the cast housing makes sense.   Not sure why the brain fart about the draw bar movement but sitting on the can thinking about it caused me to run out to check!  So, really the only real issue is the correct draw bar length and the standoffs both of which should easily be available.  THANKS so much again David.

Alex


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## davidpbest (Dec 7, 2019)

Always happy to help.  Another observation that might be useful.  Even with a custom drawbar based on the dimensions I provided, I still felt that the bushing they provided that is intended to absolutely center the drawbar in the spindle hole was a bit loose.  This idea came up in my head as I was attempting to diagnose the source of broken end mills and crappy surface finish.  That saga is fully covered *HERE*, and ultimately lead to the complete replacement of the original J-head with a new one.   Whether the bushing was contributing to my problems or not, I will never know.  Suffice it to say that in my quest to get the spindle and drive system to behave, I turned a replacement bushing that provided a better fit to both the ID of the top spindle bearing race as well as the drawbar shaft so as to guarantee that the drawbar shaft and splined head were centered in the spindle hole, and to ensure the PDB head unit was also aligned correctly (best way to align it I found was to weight down the pneumatic Head onto the splined hex-nut before tightening the mounting bolts).  Original (right) and revised shown here:






As installed:






And a reminder once you get the thing installed:  the quill must be fully elevated when you actuate the PDB or the head of the drawbar will not engage with the pneumatic drive above.  Took me a while to make raising the quill second nature when changing tools.  

Yes, I have done a lot of 304 milling.  I’m no expert, but would be happy to help if I can.  As my dad was fond of saying, “It helps if you have sharp tools and a quiet mind.”


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## 4cyclic (Dec 8, 2019)

I installed mine last year. On the invoice there are 2 items:

TR-100 S/P : Maxi Torque-Rite Power drawbar Unit with step Pulley mounting bracket kit
DB-101 : Bridgeport Step Pulley (R8) drawbar.
	

		
			
		

		
	






Hope that helps with your install.


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## Kamloopsendo (Dec 8, 2019)

Definitely helps, thanks for responding.  I wonder if the DB 101 is the draw bar designation after they made up one specifically for David Bests Unit?  I"m going to talk to the factory and the supplier tomorrow and get the right kit to finish up.  Thanks for taking the time to respond.
Alex


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## Kamloopsendo (Dec 8, 2019)

davidpbest said:


> Always happy to help.  Another observation that might be useful.  Even with a custom drawbar based on the dimensions I provided, I still felt that the bushing they provided that is intended to absolutely center the drawbar in the spindle hole was a bit loose.  This idea came up in my head as I was attempting to diagnose the source of broken end mills and crappy surface finish.  That saga is fully covered *HERE*, and ultimately lead to the complete replacement of the original J-head with a new one.   Whether the bushing was contributing to my problems or not, I will never know.  Suffice it to say that in my quest to get the spindle and drive system to behave, I turned a replacement bushing that provided a better fit to both the ID of the top spindle bearing race as well as the drawbar shaft so as to guarantee that the drawbar shaft and splined head were centered in the spindle hole, and to ensure the PDB head unit was also aligned correctly (best way to align it I found was to weight down the pneumatic Head onto the splined hex-nut before tightening the mounting bolts).  Original (right) and revised shown here:
> 
> View attachment 307391
> 
> ...


David:  I also wonder about spinning up the mill with the drawbar engaged in the Power head.  Puts a bit of wear on the air motor and if one extends the quill down with the draw bar spinning the air motor as it disengages one would expect over time to wear the splines.  Do you always extend the quill to disengage the draw bar from the power head before spinning up the quill?
Yes the only thing I've realized with 304 is that VERY sharp tooling does cut better.  I bought some 303 which machines beautifully - it gives up a bit in the mechanical properties but still pretty good stuff and MUCH easier to machine.


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## Jackle1312 (Dec 8, 2019)

I would recommend contacting the manufacturer. 
When I installed one on my Kondia I had a issue with the drawbar length. The vendor I used referred me to the manufacturer and they took care of the issue and sent the part out overnight. Cant remember how I talked to but the customer service was topnotch.


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## Kamloopsendo (Dec 8, 2019)

Jackle1312 said:


> I would recommend contacting the manufacturer.
> When I installed one on my Kondia I had a issue with the drawbar length. The vendor I used referred me to the manufacturer and they took care of the issue and sent the part out overnight. Cant remember how I talked to but the customer service was topnotch.


I will definitely be talking to the manufacturer as well as the supplier.  Looks to be a pretty simple solution.  Thanks to everyone who chimed in.
Alex


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## 4cyclic (Dec 9, 2019)

Kamloopsendo said:


> Definitely helps, thanks for responding.  I wonder if the DB 101 is the draw bar designation after they made up one specifically for David Bests Unit?  I"m going to talk to the factory and the supplier tomorrow and get the right kit to finish up.  Thanks for taking the time to respond.
> Alex



From what I understand DB 101 is their standard draw bar length, not custom. Reason is, if you need replacement they can ship out one very quickly. 

John


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## Kamloopsendo (Dec 9, 2019)

Does sound that way, I talked to their factory this morning and they recommended the DB101 and the stand off kit for the unit I have.  I talked to KBC and sounds like they'll get the parts and swap out the drawbar and obtain the stand off kit for me.  So all seems to be under control.
Alex


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## kb58 (Dec 12, 2019)

At the risk of getting off topic, with the power drawbar mounted, can the drawbar be loosened without having shop air? Asked another way, is there enough room to get a wrench onto the drawbar with the power draw bar in place? Reason I ask is because as wonderful as power draw bars are, having your compressor go down means being unable to change the cutter, or even use the mill at all, or so it seems.


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## Kamloopsendo (Dec 12, 2019)

Not installed yet so don't know about room but does not look like it.  But if push comes to shove 3 bolds and the power head is off and you're back in business pretty quick


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## Jackle1312 (Dec 12, 2019)

The step pulley adapter has 1 7/16 spacers. I didn't check the drawbar when I installed it to see if a wrench would work.


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## davidpbest (Dec 19, 2019)

Kamloopsendo said:


> David:  I also wonder about spinning up the mill with the drawbar engaged in the Power head.  Puts a bit of wear on the air motor and if one extends the quill down with the draw bar spinning the air motor as it disengages one would expect over time to wear the splines.  Do you always extend the quill to disengage the draw bar from the power head before spinning up the quill?



I do not lower the quill before starting the spindle running - and frankly never thought about it.   One of the reasons I went with the Torque-Rite was to get (hopefully) a better quality product all around - in contrast to building my own with a Harbor Freight air motor - .   The splines on the drawbar they supplied are hardened to something like Rockwell 50, so I'm not worried about wear on the drawbar.   Since the drive spline socket in the air motor assembly is custom (not just a hex socket), I assume it's equally tough.   Time will tell.


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## davidpbest (Dec 20, 2019)

kb58 said:


> At the risk of getting off topic, with the power drawbar mounted, can the drawbar be loosened without having shop air? Asked another way, is there enough room to get a wrench onto the drawbar with the power draw bar in place? Reason I ask is because as wonderful as power draw bars are, having your compressor go down means being unable to change the cutter, or even use the mill at all, or so it seems.



Unless you remove the three 1/4-20 socket head cap screws and take off the head unit, you can not access the top of the drawbar to remove it manually.   Even if you do take off the head unit, you'll find a splined head and will need a 12-point box-end wrench to grip it ( I think it's 15mm but could be mis-remembering).


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## davidpbest (Dec 20, 2019)

Kamloopsendo said:


> Does sound that way, I talked to their factory this morning and they recommended the DB101 and the stand off kit for the unit I have.  I talked to KBC and sounds like they'll get the parts and swap out the drawbar and obtain the stand off kit for me.  So all seems to be under control.
> Alex



Curious if you're back up and running and how the experience was getting the new drawbar and stand-off kit.


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## Kamloopsendo (Dec 20, 2019)

David:  For some reason I just picked up your responses, I was wondering if you had received my question about dropping the draw bar out of the air motor.   Not sure what I'll do but think being basically lazy I won't bother unless I'm using high spindle speeds.   
As to up and running - In mid January if I'm lucky.  Just finally sorted out between KBC and the Maxi-Torque manufacturer so parts are ordered but cross border shopping adds time so my guess is I'll have the parts mid January (maybe earlier - we'll see)  The install looks pretty simple and should have the control stuff in place before I get the mounting bracket and drawbar.  
I"ll let you know, thanks for the help David and Merry Christmas!!
Alex


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## davidpbest (Dec 20, 2019)

Kamloopsendo said:


> David:  For some reason I just picked up your responses, I was wondering if you had received my question about dropping the draw bar out of the air motor.   Not sure what I'll do but think being basically lazy I won't bother unless I'm using high spindle speeds.
> As to up and running - In mid January if I'm lucky.  Just finally sorted out between KBC and the Maxi-Torque manufacturer so parts are ordered but cross border shopping adds time so my guess is I'll have the parts mid January (maybe earlier - we'll see)  The install looks pretty simple and should have the control stuff in place before I get the mounting bracket and drawbar.
> I"ll let you know, thanks for the help David and Merry Christmas!!
> Alex


I did see that question and replied to it.   Just scroll back upward and you'll see that reply.


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## Kamloopsendo (Dec 20, 2019)

Yes, I saw and read your response David, I was just not watching I guess and had missed it when you posted.  Have a great Christmas
Alex


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## Stainless Steve (Dec 27, 2019)

test post


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## Stainless Steve (Dec 28, 2019)

Happy Holidays to everyone!  I just joined the Hobby-Machinist on Dec. 1st. and was pleasantly surprised to find all of this information on the installation of the Maxi Torque-Rite drawbar system with step pulleys.

Recently, my machinist friend and I purchased two of these Maxi Torque units (new, old stock in open boxes) and they were both TR 100 DB164, which I know is for Jet Model JTM4VS and Clausing Atlas machines (R8).  I know these drawbars are not the correct length for our Bridgeport step pulley mills.

Based upon the information that is posted on this forum, I need to obtain DB-101 drawbars.  I spoke with a gentleman at *All Machine Parts* the other day and he told me the drawbar would be $65 and the mounting kit is $85.  Apparently the kit also includes a plastic alignment fixture.  I know from looking at my mill that this mounting bracket must have a relief on the back side to clear the motor housing.  The pictures you have posted also show a relief on the front side for the spindle brake.

I am entertaining the idea of making my own mounting plate & spacers & my own alignment tool.  This is one of my hobbies, I’m retired, and I have this equipment sitting here and I should be putting it to good use.  I’m also a 304SS nut – and “yes”, you do need sharp tools and a quiet mind”.  I think it might be a good idea to capture these three 1-7/16” spacers in the bracket.  My thought would be to add a shoulder at the top of these spacers and then slide them into the bracket with Loctite. This should simplify the assembly process.  I would need to design my own alignment fixture.

In all of the photos that were posted, it appears the step pulley mounting bracket is “thicker” than the mounting plate on the Maxi Torque unit, which measures a little over .375”.  If anyone can supply the thickness of that *All Machine Parts* Maxi Torque mounting bracket that would be very helpful.    

I do have some concerns about the alignment of this assembly with the c/l of the drawbar/ spindle after this PDB assembly is bolted in place.  I did see David’s post regarding the reworked drawbar bushing and I will have to take a look at that as well.  

Did any of you have any alignment issues with the *All Machine Parts* pieces after the fasteners were installed in the belt housing?  I ask this question because I spoke with someone that had recently installed this *All Machine Parts* kit on a J-Head and he told me he had to go back and open up the spacer mounting holes in the bracket after he had drilled and tapped the pulley housing and installed the fasteners.         

 Any input that you have would be greatly appreciated!
Steve


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## Kamloopsendo (Dec 28, 2019)

Steve:  for what it's worth I've ordered the bracket kit (SP100 bracket kit from Machine Tool Products) thru KBC and it comes direct from the manufacturer of the Maxi-Torque unit "Machine Tool Products".  I've not received it yet so not installed and my machine is a Taiwanese clone of a bridgeport so again maybe slightly different from yours. These guys (Machine Tool Products) were very helpful when I talked to them as what KBC had sent me was for a generic Variable pitch sheave drive style mill.   It might be worth a phone call to these guys given that they manufactured the unit and likely know the most about mounting it to various machine styes.  Phone number is 317-593-2034, they were very helpful.
Alex


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## Stainless Steve (Dec 29, 2019)

Alex:  Thank you for the information.  I will give Machine Tool Products a call.  Steve


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