# PM45 - Moving the head height crank to the front.



## GaryK (Apr 10, 2013)

One thing I  don't like about small mills is the adjustment for setting the height of  the head is on the column on the back of the machine.
Very hard to reach and uncomfortable to crank. Also with my DRO on the opposite side of the machine it made it a stretching act to
read it while cranking.

I decided a long time ago that I was going to fix that. Here is the solution that I can up with. All it takes is some roller chain, two sprockets
and two miter gears for purchased parts.

The only limitation is the table can't be too far from the column or too far to the left. The crank will hit the table if it is. This is not that big a deal
since 90% of things are done with the table near the center of the spindle. If it is necessary to move the table out of the way it's well worth it.

I am working on a couple of improvements to remove this limitation though. I am also looking at using a wheel rather than the crank. I'm just not
sure about the leverage I will get on it. 

Right no the crank is fixed with the same set screw that attaches it to the column. I was thing about add a couple of slots in it and a pin through
the shaft to allow you to re-clock it and turn it around like on a knee mill.

We shall see how these work out. If you would like prints and a parts list let me know and I will create them.

One good thing is that it doesn't require any modification at all to the mill and can be put back exactly like it was.

Gary


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## Bama Steve (Apr 10, 2013)

This is an excellent upgrade and impressive workmanship.

I wonder if you milled some fittings for these things --> http://www.jegs.com/i/Titan/413/309...&cagpspn=pla&gclid=CJy9oNWEwbYCFQennQodvQoA7A   and moved your crank to the left-outer-edge of the shaving pan, if that would completely correct your table movement limitation?



Looks good, Sir . . .


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## 8ntsane (Apr 10, 2013)

Nice work Gary, that should make life a bit easyer.  :thumbzup:


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## davidh (Apr 10, 2013)

looks nice,  still waiting for my mill, im jealous. . . .  and you could even go so far as to put power to it. . . like a cordless drill ?


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## darkzero (Apr 10, 2013)

Pretty slick Gary, I like it. I thought for sure you were going to make something powered but that would be cheating even more.


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## Ray C (Apr 10, 2013)

Good going there Gary...  Oh how I hate moving that head larger distances!  I'm still waiting for the right gear motor to come my way.  That crazy crank takes a good bit of torque.


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## GaryK (Apr 11, 2013)

darkzero said:


> Pretty slick Gary, I like it. I thought for sure you were going to make something powered but that would be cheating even more.





Ray C said:


> Good going there Gary... Oh how I hate moving that head larger distances! I'm still waiting for the right gear motor to come my way. That crazy crank takes a good bit of torque.



I may still add a motor, but I want precise control for positioning. Stopping a motor exactly where you need it is impossible. If I do add a motor it will just be to do gross movements.
Then since it will be geared it will have to be disengaged so that I could use the handle for precise positioning.

I'll also change the ration of the sprockets not only to make it easier on the motor, but give me real fine control with the handle. Like Ray, I'll be waiting for the right motor. I want somewhere between
60-120 RPM at the output shaft to move the head quickly.

Gary


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## Bama Steve (Apr 11, 2013)

Check here -->  http://www.surpluscenter.com/sort.asp?catname=electric&keyword=GIAD


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## GaryK (Apr 11, 2013)

Bama Steve said:


> Check here -->  http://www.surpluscenter.com/sort.asp?catname=electric&keyword=GIAD



That's one of the places I always check, but none of the motors have enough torque.

That's the place I bought the sprockets and chain for this project.

Gary


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## GaryK (Apr 11, 2013)

Does anyone have a torque wrench that can check how much torque is needed to lift the head?

The lowest my wrench goes is 40 ft-lb/55Nm.

Gary


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## Bama Steve (Apr 12, 2013)

Will this work?  -->  http://www.amazon.com/Park-Tool-TW-...9090&sr=1-4&keywords=inch-pound+torque+wrench

Best!



- - - Updated - - -

Will this work?  -->  http://www.amazon.com/Park-Tool-TW-2-Torque-Wrench/dp/B000NVAHMW/ref=sr_1_4?s=hi&ie=UTF8&qid=1365809090&sr=1-4&keywords=inch-pound+torque+wrench

Best!


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## darkzero (Apr 12, 2013)

GaryK said:


> Does anyone have a torque wrench that can check how much torque is needed to lift the head?
> 
> The lowest my wrench goes is 40 ft-lb/55Nm.
> 
> Gary



With how tight I have my gibs currently adjusted (any tighter causes the head to skip when lowering), I get about 8 ft-lbs with my Snap-On digital to get it moving. But this was just a quick & dirty method of measuring so YMMV. I'll see if I have something handy to take a reading directly on the shaft to eliminate the error of the Z handle.

But for now, the highest reading I got was 9.2 ft-lbs to break the tension to get it moving. Max continous movement was roughly around 5-6 ft-lbs. 5ft-lbs is the lowest reading on this wrench. With my clicker type torque wrench with a min reading of 10ft-lbs, the head moved before reaching the 10ft-lbs setting.


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## MikeWi (Apr 13, 2013)

There's a way to calculate the actual torque value from the wrench's reading and the length of that handle it's hooked to.
http://www.freeinfostuff.com/TorqueExtension/TorqueExtension.htm


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## GaryK (Apr 13, 2013)

darkzero said:


> With how tight I have my gibs currently adjusted (any tighter causes the head to skip when lowering), I get about 8 ft-lbs with my Snap-On digital to get it moving. But this was just a quick & dirty method of measuring so YMMV. I'll see if I have something handy to take a reading directly on the shaft to eliminate the error of the Z handle.
> 
> But for now, the highest reading I got was 9.2 ft-lbs to break the tension to get it moving. Max continous movement was roughly around 5-6 ft-lbs. 5ft-lbs is the lowest reading on this wrench. With my clicker type torque wrench with a min reading of 10ft-lbs, the head moved before reaching the 10ft-lbs setting.



Very cool tool! But that's not the way to measure it. You would need to do some math to come up with the correct number. Kind of like you would using a crows foot.

I make this out of some 1" CRS I had laying around. I could have tapped the end and screwed in a hex head bolt real tight, but I just used my indexer to the cut the hex.




But my clicker wouldn't go low enough. I can't justify buying a torque wrench just for this.

Gary


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## darkzero (Apr 13, 2013)

GaryK said:


> Very cool tool! But that's not the way to measure it. You would need to do some math to come up with the correct number. Kind of like you would using a crows foot.
> 
> I make this out of some 1" CRS I had laying around. I could have tapped the end and screwed in a hex head bolt real tight, but I just used my indexer to the cut the hex.



Yeah I know, that's why I mentioned that in my post. I figured since you know the length of the handle you could just do the math. 

You got me curious so when I got home I made a proper adapter. Funny cause using a hex head is exactly what I did since it was easier & I didn't feel like seting up the super spacer.

So here you go, I'll save you math..... I get about 6-7 ft-lbs consistently turning it. If I pull real slow it takes about 11 ft-lbs to break the tension to start movement. I forgot to test lowering the head before I put the handle back on but I didn't think it was necessary anyway. Since I have the adapter now it's easy to take more measurements if you need them.


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## Tony Wells (Apr 13, 2013)

What? None of you guys has an in/lb torque wrench? Need to borrow mine, Gary, or is this academic?


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## Ray C (Apr 13, 2013)

I've got an in-oz torque wrench and think I used it once.  -Not planning on testing the PM 45 crank though...  About a year ago, I set out to motorize mine and did a quick test by rigging-up a bar of some sort, held it horizontal and put gym weights on it until it moved.  Don't remember the exact dimensions of the bar but it came out to around 10-11ft-lb because I jotted the number down with a marker on the column.  My plan was to find a gear motor with at least 25ft-lb but I couldn't find one at the RPM and price-point I was comfortable with.  -Never did get around to making something.


I gave somebody down there a "Thanks" for testing with a torque wrench because, it pretty-much validated my prior test.

Ray



Tony Wells said:


> What? None of you guys has an in/lb torque wrench? Need to borrow mine, Gary, or is this academic?


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## GaryK (Apr 13, 2013)

Tony Wells said:


> What? None of you guys has an in/lb torque wrench? Need to borrow mine, Gary, or is this academic?



Thanks Tony, but it's pretty much academic now.

Gary


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## GaryK (Apr 13, 2013)

darkzero said:


> Yeah I know, that's why I mentioned that in my post. I figured since you know the length of the handle you could just do the math.
> 
> You got me curious so when I got home I made a proper adapter. Funny cause using a hex head is exactly what I did since it was easier & I didn't feel like seting up the super spacer.
> 
> So here you go, I'll save you math..... I get about 6-7 ft-lbs consistently turning it. If I pull real slow it takes about 11 ft-lbs to break the tension to start movement. I forgot to test lowering the head before I put the handle back on but I didn't think it was necessary anyway. Since I have the adapter now it's easy to take more measurements if you need them.



Thanks Will,

Now I just need to find a reversible AC gear motor with over 168 in.-lb (double your reading) of torque at 60+ RPM. All this at a decent price.

After using the front crank for a while I find that it's so much better. It's great even without a motor.

Gary


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## darkzero (Apr 13, 2013)

GaryK said:


> Thanks Will,
> 
> Now I just need to find a reversible AC gear motor with over 168 in.-lb (double your reading) of torque at 60+ RPM. All this at a decent price.
> 
> ...



Your welcome Gary, anytime.


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## GaryK (Apr 14, 2013)

I finally made a handle for that wheel I mentioned in my first post. The wheel removes the limitations of the x-axis getting in the way.
It is just as easy to crank the head down, but I need two hands to crank it up. Hot that big of a deal since it's right in front of
you. It beats reaching across the table the crank at arms length.

In the last picture I put on the old handle to show just how much difference there is. A lot less leverage, but still works great!

Looks pretty cool also.


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## woodrowm (Apr 15, 2013)

GaryK said:


> One thing I  don't like about small mills is the adjustment for setting the height of  the head is on the column on the back of the machine.
> Very hard to reach and uncomfortable to crank. Also with my DRO on the opposite side of the machine it made it a stretching act to
> read it while cranking.
> 
> ...



Good morning - Hey great work, plans for this would be great as I have the same mill and the same problem.

Thanks,
Woodrow


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## sanddan (Apr 15, 2013)

Here's a link to the motor I put on my mill. It is 70 in-lbs at 160 rpm which will move the head but I had already installed gas springs to make it easier to raise the head when I was still using the crank.

http://www.hobby-machinist.com/showthread.php/10056-Motor-for-PM-45-Hand-Crank


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## GaryK (Apr 15, 2013)

sanddan said:


> Here's a link to the motor I put on my mill. It is 70 in-lbs at 160 rpm which will move the head but I had already installed gas springs to make it easier to raise the head when I was still using the crank.
> 
> http://www.hobby-machinist.com/showthread.php/10056-Motor-for-PM-45-Hand-Crank




Thanks for the link. Do you have the part number and source for the motor you used?

Gary


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## skeeter355 (Apr 15, 2013)

Gary I would also like to see the plans. Great setup!

Skeeter


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## GaryK (Apr 17, 2013)

skeeter355 said:


> Gary I would also like to see the plans. Great setup!
> 
> Skeeter



You can find the drawings HERE.

Gary


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## GaryK (Apr 19, 2013)

Here is a video showing the handle being used:

[video=youtube_share;OcfJtyQAsjU]http://youtu.be/OcfJtyQAsjU[/video]

The noises you hear are the following. The clicking is just the handle I made clicking on the mounting bolt,
and the rumble is the chain going around the sprocket. Perfectly normal.

Gary


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## qualitymachinetools (Apr 20, 2013)

Wow Gary,
 Thats pretty slick, I like it!


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## GaryK (May 4, 2013)

Thanks Matt!



I thought I would guys you guys an update.

Now that I have used the handle for a couple of weeks I have to tell you that I don't dread raising and lowering the head anymore.
I used to try to plan out all my milling and drilling operations to minimize moving the head and now I don't.

With the smaller diameter handle it takes more effort to lift the head but it's right in front of your body and using both hands it a breeze.
It takes me 15 seconds to go from milling to drilling.

Moving the head down is nothing. Not much more than turning the X or Y axis wheel.

All in all I think it's one of the best improvements you can make.

Gary


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## woodrowm (May 14, 2013)

Good morning - Hey do the base plates fit flush to the base of the mill. The reason that I ask is that if I use your measurement for the location of the hole for the base plate the is about a 1/4" gap between the base and the mill. This is my first project and it is turning out great.

Thanks,
Woodrow


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## Daver (May 14, 2013)

I don't have a PM45, so take this as just a brain storm kind of idea (drizzle more like it).
If you could make the crank work like a ratchet, then you could keep the crank and eliminate the table limitation.  Use full swing of crank when table is not in the way, and half-moon crank motions (with ratchet action) when table is too close.

Just throwing that out there, not sure if it is anymore practical or doable than the wheel.


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## GaryK (May 14, 2013)

woodrowm said:


> Good morning - Hey do the base plates fit flush to the base of the mill. The reason that I ask is that if I use your measurement for the location of the hole for the base plate the is about a 1/4" gap between the base and the mill. This is my first project and it is turning out great.
> 
> Thanks,
> Woodrow



There is a radius in the corner so the gap is normal. You could radius your part to get it a little closer.

Please post some pictures of your progress!

Gary


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## GaryK (May 14, 2013)

Daver said:


> I don't have a PM45, so take this as just a brain storm kind of idea (drizzle more like it).
> If you could make the crank work like a ratchet, then you could keep the crank and eliminate the table limitation.  Use full swing of crank when table is not in the way, and half-moon crank motions (with ratchet action) when table is too close.
> 
> Just throwing that out there, not sure if it is anymore practical or doable than the wheel.



I hadn't thought of that, but with my little wheel, I'm not going to invest anymore time into it.

Someone else might take your idea an run with it though.

Thanks,

Gary


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## GaryK (May 29, 2013)

Someone asked about the gears I used and I forgot that the part number I supplied on the print is generic.

The complete part number and description is:

Boston Gear L112Y Miter Gear, 1:1 Ratio, 20 Degree Pressure Angle, 0.500" Bore, 16 Pitch, 24 Teeth, Steel


Gary[h=1][/h]


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## mskobier (Jun 28, 2013)

All,
     I joined this group a few months ago when I was looking for an RF-45 class mill. I settled on the PM-45. After the machine arrived, and I got it set up, I discovered that I hated the left side mounted head crank and decided to convert it over to power lift. It takes 130 turns for full travel of the head! 

I did a a lot of internet research and remembered that the Grizzly G0755 mill comes with a powered head lift. I downloaded the owners manual and looked at the specifications of the lift head. It is rated at 1/8hp and is a gear head motor. It did not say what the rpm or torque rating was. I measured the handle of the crank, attached a cloth bag to the handle and started adding 1lb weights until the handle started to lift the head.  It took about 10lbs to get it to move. I added another pound for good measure and multiplied the handle length (8") by the weight to get the in-lbs needed to move the handle. That works out to about 90 in-lbs.  

I did a bit of ebay searching and found a gear head motor manufactured by Bodine that was rated at 1/6hp,  135in-lbs of torque, and turned at a rate of 57 rpm. A bit slower than I would have liked, but plenty of power to do the job. The motor also was 120V AC and was a four wire reversible. I located one of these motors in very good used shape for about $100.00. The output shaft is 3/4". The Z axis lead screw has the top end turned down to .780". A little more thinking and realized a lovejoy coupling (AL-075) with a 3/4" bore could easily be turned out to .780". So I purchased the necessary parts for the coupling. After a bit more measuring, I figured I needed to make the motor mount approx. 1.75" thick so there would be enough clearance for the motor and couplings with just a little bit of extra for clearances. Then figured out the wiring necessary to make the motor reversible with only using one toggle switch. The switch I am using is a mil spec, sealed toggle that is spring loaded center off and momentary contact for the two on positions. (momentary on- off- momentary on). It is a 4PDT center off switch. It also came from ebay. So with the motor, switch, misc wiring and hardware, I am into the power lift approx. $150.00. With a little bit of luck, I will have the lift motor installed this weekend. One large obstacle is that the z axis lead screw is not keyed. I will be building a support frame for the head and locking it in place. I will then remove the lead screw, mount it in the vice and cut a 1/8" key slot in the shaft. After fitting the lower lovejoy to the lead screw, I will reinstall the screw and mount the head. Again, hopefully this will all be completed this weekend. 

I weighed the head on my mill. It comes in at 145lbs. I found a source of 120lb rated gas springs that if this all works out like I think it will, then I will purchase a set, install the springs, and replace the motor with one with a faster speed. The ones I am considering turns at 85 or 115 rpm with 90 or 68 in-lbs of torque. With the gas springs taking the gross majority of the head weight, it will not take much torque to move it.

Anyway, sorry for the long post. I figure you guys may be interested in how I am adding power lift to the head of my PM-45. I'll try and take some pictures during the mod this weekend.


Mitch


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## GaryK (Jun 29, 2013)

I'd really like to see how that turns out! Sounds great to me.

Keep us posted!

Gary


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## mskobier (Jul 4, 2013)

All,
    I was just reading my post and noticed an error. The head on my mill weight 245lbs not 145lbs as I originally posted. Please forgive my error.

Mitch


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## sanddan (Jul 4, 2013)

mskobier said:


> All,
> I was just reading my post and noticed an error. The head on my mill weight 245lbs not 145lbs as I originally posted. Please forgive my error.
> 
> Mitch



That makes sense as I used two 100 lb springs and it seemed to balance the head quite well.


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## 7HC (Aug 9, 2013)

GaryK said:


> I may still add a motor, but I want precise control for positioning. Stopping a motor exactly where you need it is impossible. Gary



Not if you use a stepper motor.  Stepper or servo motors can give very fine control, which is why they're used for CNC.

M


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