# Precision Matthews X Axis Power Feed



## erikmannie (Sep 25, 2019)

I just bought a PM-25MV with a DRO, and I am very happy with it. I am still trying to warm up to the x-axis power feed.

A friend and I took a whole day to (1) clean the shipping grease off the mill, and (2) install the power feed. I mistakenly assumed that we would successfully install the power feed in one day. The installation has been delayed because (1) I cracked the cast aluminum bracket by overtightening the steel mounting bolt, and (2) mounting the limit switch to the saddle requires some planning.

PM responded very quickly and shipped me out a new cast aluminum bracket, free of charge.

I was not aware that PM recommends drilling and tapping the saddle for the limit switch. The bolts provided are M8 X 1.25.

My buddy and I went down the wrong path for awhile when we tried to mount the limit switch to the table, even though we were *both* looking at *both* sets of instructions. My poor excuse for this mistake is that we had just finished mounting the two travel stops to the table (which requires grinding slide-in T-nuts to fit the dovetails on the front of the table). It is important to understand that the limit switch is mounted to the saddle.

The limit switch mounting plate that comes with the x-axis power feed kit is a flat carbon steel plate. It has four small tapped holes for the plastic limit switch to attach to it. The point here is that it would be very simple to fabricate any mounting plate that you would want. The mounting plate provided is too tall for a PM-25MV, and PM said that cutting off the extra material is an acceptable solution.

Here are the problems that I am still facing:
(1) the limit switch is so tall that the cord on the bottom is right up against the ways for the y-axis travel. Somebody posted here that this cord sometimes snags on the saddle, and
(2) the top of the limit switch would be about 1mm from the bottom of my table vise (this limit switch is almost too tall to be mounted), and
(3) in my opinion, the level of quality of the limit switch is not at the level of quality of either the milling machine or the x-axis power feed drive unit. I am reluctant to drill and tap a really nice mill to mount what appears to me to be an economy grade switch.

At least one person on this forum has posted that he routinely cuts off the limit switches and stays mindful of the situation. Like him, I would be at the helm while the spindle is going. PM says that it is too risky to use the x-axis power feed without the limit switch, but I feel like putting some red pinstriping on the table scale would keep me out of trouble. What could possibly go wrong? (sarcasm)

So I made this post to poll the forum as to whether or not it would be acceptable to cut off the limit switch, as well as clarify that one mounts the limit switch to the table which requires drilling and tapping the saddle and/or modifying the limit switch mounting plate.

Finally, one can fab a mounting plate *that uses the existing threaded holes in the saddle* (used for a zero indicator which gets taken off to make room for the limit switch), but this setup is quite clearly not so rigid. PM recommended to me that drilling and tapping the saddle is the preferred method.

So do you guys think that I should mount it or cut off and stay mindful?


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## Firstgear (Sep 25, 2019)

Accidents happen....mount it.


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## erikmannie (Sep 25, 2019)

Firstgear said:


> Accidents happen....mount it.


Safety: I like it!

Here is the assembled height of the limit switch. The cord will emanate to the left, which is opposite of how it is in the picture.


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## erikmannie (Sep 25, 2019)

Here is the rear of the limit switch mounting plate. The *slots* are for bolting this mounting plate to the "spacer block" which I will call the spacer. This spacer brings the switch out to where the switch needs to be to meet the pair of stops (left and right) which are mounted in the dovetail slot at the front of the table.


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## erikmannie (Sep 25, 2019)

The instructions say to use graphite based grease on the gears. Ideally it would be NLGI No. 2 grease. I found this at the auto supply store.


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## erikmannie (Sep 25, 2019)

I am not sure if I will still be able to use the hard stops (one of which is shown at the center of this photo) once I mount the pair of stops that come with the x-axis power feed kit. Does anybody know of I need to take these off?


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## erikmannie (Sep 25, 2019)

Here is the work area where on mounts the limit switch. I have referred to this area as the front of the saddle.


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## erikmannie (Sep 25, 2019)

On a stock PM-25MV, there is a zero mount. This must come off to make room for the limit switch.


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## erikmannie (Sep 25, 2019)

The mounting screws leave behind two threaded holes that one could use to anchor a custom spacer (which would almost certainly necessitate a custom limit switch mounting plate).


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## erikmannie (Sep 25, 2019)

Here is the spacer provided in the PM kit. The idea is to bolt this to the saddle, and the limit switch mounting plate bolts to this spacer.


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## mksj (Sep 25, 2019)

The mounting instructions are generic. The location of the limit switch depends on the axis and the machine. On the X axis it is typically mounted to the saddle as shown in the directions. Almost all drives are NOT machine specific and almost always requires fabricating brackets, standoffs, etc. to make them work. One of the biggest mistakes I see people do with DRO and drive limit switch installs is to try to use the stock brackets and kludge something together. Most of the time you need to mock up everything, make sure you have the appropriate clearances and then mount everything.

The wire at the bottom of the switch can be held in place with cable restraints to prevent it from interfering with other machine components. I would have no issues with using the saddle threaded holes or tapping new ones being very careful to not thread into something other than the saddle. In this case use the current holes in the saddle make a bracket and countersink the heads, then mount the switch to the bracket.

Quality of components is proportional to the price for the most part, but there are enough of these installed that I would be confident that although the switch my not look high end, that it will work. If I had a limitation as to the switch size or I wanted higher quality there are plunger type limit switches that could be used. I have installed these on custom axis drives that I have made.


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## erikmannie (Sep 25, 2019)

Speaking of spacers, PM provides a pair of spacers that one can use instead of the single spacer pictured above. One of these alternate spacers is shown below.


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## erikmannie (Sep 25, 2019)

I will probably use the single spacer:


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## erikmannie (Sep 25, 2019)

Here is a photo of the height of the limit switch and the front of the saddle:


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## erikmannie (Sep 25, 2019)

Here is the max height that I have to work with.


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## erikmannie (Sep 25, 2019)

Here are the stops provided in the PM power feed kit. They mount in the dovetail slot at the front of the table:


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## erikmannie (Sep 25, 2019)

It looks like I will have to remove the limit switch when I access the ball oiler. How often do you guys put oil in these?

I also note that the forum software sometimes rotates my pictures.


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## erikmannie (Sep 25, 2019)

So what I was calling the spacer will now be referred to as the standoff.

My dad came by and said that drilling and tapping the saddle would be more work than using the existing threaded holes. I wonder what the saddle is made of; it appears to be a casting.

So I am moving forward with a plan to drill two holes in the standoff that came in the kit. The threaded holes in the saddle are M5 X 0.8. A 20mm shank is a little too long and a 15mm shank may be a little too short. I found some in 16 and 18mm. I will counterbore the standoff so that the limit switch can be flush up against it.

I will cut a clearance out of the standoff so that I can access the ball oiler. This would require me to remove only the limit switch when I want to oil here.


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## erikmannie (Sep 25, 2019)

Even though I used plenty of grease, the grease doesn't seem to stay on the drive gear. I operated the power feed back and forth about 10 times.


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## erikmannie (Sep 25, 2019)

I received the replacement bracket from PM. I will go easy on this one.


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## erikmannie (Sep 25, 2019)

I never mentioned the part of the installation that occurs where the left handwheel was. Removing the handwheel and putting the power feed on there is straightforward. It is very east to increase or decrease the engagement between the gears by raising and lowering the power feed (motor) unit. Obviously, it is important to keep that bracket level along the y-axis of the table.


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## higgite (Sep 25, 2019)

Going by the top pic in post #14, I’d look at dismounting the limit switch from the bracket, turning the bracket 180 degrees and remounting the LS lower down on the saddle. I think that would allow you to align the LS buttons with the slot in the table and, therefore, with the stops. As pictured with the buttons above the slot, it looks pretty iffy that the stops would hit the LS buttons reliably.

Tom


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## petertha (Sep 26, 2019)

erikmannie said:


> The installation has been delayed because (1) I cracked the cast aluminum bracket by overtightening the steel mounting bolt, and (2) mounting the limit switch to the saddle requires some planning. PM responded very quickly and shipped me out a new cast aluminum bracket, free of charge.



Not sure if your aluminum bracket is like the one I had on my RF-45 mill which also cracked. I tossed mine & made this modification which ran much better FWIW. https://www.hobby-machinist.com/threads/rf-45-mill-power-feed-mount-improvement.64766/


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## erikmannie (Sep 26, 2019)

petertha said:


> Not sure if your aluminum bracket is like the one I had on my RF-45 mill which also cracked. I tossed mine & made this modification which ran much better FWIW. https://www.hobby-machinist.com/threads/rf-45-mill-power-feed-mount-improvement.64766/


The replacement bracket that you made is beautiful. I hope to have the skills to do that one day.


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## erikmannie (Sep 29, 2019)

I modified the brackets that came in the kit.

I clearanced the thick one (the one that mounts to the saddle) so that I could access the ball oiler. 

I shortened the thinner bracket (the one that mounts to the limit switch) by 11mm so that it would clear the base.


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## erikmannie (Sep 29, 2019)

Does anybody have a recommendation for a torque spec for the bolts that mount the cast aluminum power feed bracket to the table? I don't want to crack another bracket.

I will go easy and post here how much I tightened it.

I can't mount this yet because I am still waiting on my 16mm (or 18mm) M5 bolts that will be used to connect the modified bracket above to the saddle.


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## wrmiller (Sep 29, 2019)

erikmannie said:


> Does anybody have a recommendation for a torque spec for the bolts that mount the cast aluminum power feed bracket to the table? I don't want to crack another bracket.
> 
> I will go easy and post here how much I tightened it.
> 
> I can't mount this yet because I am still waiting on my 16mm (or 18mm) M5 bolts that will be used to connect the modified bracket above to the saddle.



How about a touch of blue loctite and 'snug'. Well it worked for me anyway.


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## pontiac428 (Sep 29, 2019)

Just snug enough to hold the bracket from moving. It's not a support element and it does not need to hold your body weight, so choke up on that wrench halfway and just apply snug pressure.


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## erikmannie (Sep 29, 2019)

Helpful info on the tightening pressure.  It had not occurred to me to use Loctite.


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## WyoGreen (Sep 29, 2019)

Here's a picture of the bracket I made for my PM30 to replace that clamp on bracket. Not the prettiest bracket, but functional, and it makes the ball oiler   available again, and frees up the space at the end of the table that the clamp on bracket steals.


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## erikmannie (Sep 30, 2019)

WyoGreen said:


> Here's a picture of the bracket I made for my PM30 to replace that clamp on bracket. Not the prettiest bracket, but functional, and it makes the ball oiler   available again, and frees up the space at the end of the table that the clamp on bracket steals.
> View attachment 302964


Ugh, another blocked ball oiler. I am just finding out now that the ball oiler over there will be blocked with the power feed kit. Apparently this power feed kit blocks _*two*_ ball oilers.

Did you have to drill and tap the table to attach your custom bracket?

I test fitted the switch with my modified brackets, and realized that I will have to use spacers to get the dust cover over the limit switch. *I looked online and most of the installs shown do not use the dust cover*. I attached a picture of this dust cover below. It serves to protect the switch from coolant and chips.


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## erikmannie (Sep 30, 2019)

The dust cover has two springs in it.

In my first post of this thread, I said that I was still trying to warm up to this power feed kit. At this point, I wish that I would not have bought it. Turning the x axis handwheel by hand is starting to look like the smoother path here.

First I will try *mounting all the parts included in the kit*, which will include a longer bolt and some washers so the dust cover fits. Spacing it out more takes the limit switch off center of the stop plungers, but it still makes contact. If it doesn't work reliably, I might run it without the dust cover.

I am also leaving the door open to removing the whole x axis power feed kit, setting it aside and going back to manual feeding. I don't imagine that PM would accept the return with the modified brackets.

If anybody from PM is reading this, the power feed kit that I bought said "Fits PM-25MV Only", so I don't know how that allows for the dust cover to fit if the customer has to (1) put it together only to realize that the dust cover interferes with the mounting bracket, and (2) go buy washers and longer bolts. Getting this kit installed is taking way longer than I could ever have imagined.

This power feed kit came in a box marked "Fits PM-25MV Only"; it would only take a little review of the engineering to allow it to be closer to bolting on. This could also include maintaining access to the ball oilers.

If one is willing to drill and tap their saddle, then the kit come with a pair of "alternate" mounting brackets that would _*not*_ interfere with the dust cover. One is pictured below. If you want to use the dust cover, plan on using these and drilling and tapping the saddle.


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## erikmannie (Sep 30, 2019)

So I’ve decided that I will not mount this power feed kit because I would rather have access to those two ball oilers.

The bracketry requires so many modifications to get it to mount. Further modifications for the purpose of maintaining access to the two blocked ball oilers would be too much.

I bought the kit hoping for more or less of a bolt on. Losing access to the two ball oilers is unexpected.

So now I will just try to return this kit to PM.  I sent them a detailed email, and they asked for photos. They said that they sell tons of these and “no one has ever said anything about any problems with it in the past”, so the power feed kit had a perfect track record until I came along.


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## pontiac428 (Sep 30, 2019)

Nice job, @WyoGreen .  When I got my power feed, I was a little put off by the cast aluminum and I immediately went online to see what the deal was.  That's where I saw photos of broken castings from overtightening; lesson noted.  I did see another thread somewhere on the wide wide web where a user remade the whole assembly, mounting it to the lead screw support like a Bridgeport.  That writeup should be searchable, if that's a route you want to go, Erik.  In the end, I used the supplied mount.  It's been a year and I haven't had to touch it.  It's a modification that I don't know how I ever lived without.  Not for the hand cranking (I don't mind that), but the control I have over finish is so much better.


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## erikmannie (Sep 30, 2019)

pontiac428 said:


> Nice job, @WyoGreen .  When I got my power feed, I was a little put off by the cast aluminum and I immediately went online to see what the deal was.  That's where I saw photos of broken castings from overtightening; lesson noted.  I did see another thread somewhere on the wide wide web where a user remade the whole assembly, mounting it to the lead screw support like a Bridgeport.  That writeup should be searchable, if that's a route you want to go, Erik.  In the end, I used the supplied mount.  It's been a year and I haven't had to touch it.  It's a modification that I don't know how I ever lived without.  Not for the hand cranking (I don't mind that), but the control I have over finish is so much better.


The control over the finish would be worth the extra effort of getting this kit to mount.

I will keep an open mind and be patient. I had thought that I would just bolt on the power feed kit (I budgeted two guys and four hours). I had hoped to be using the mill already, and now I am headed off to find longer M8 bolts and washers. I see that I can also file a relief into the dust cover to bring it flush to the (saddle) mounting bracket.

My general problem is that I have too many (4) unfinished projects. I have put all of those on hold until I got the mill going. Working a full time job leaves little time to tinker in the garage, but I'm sure everybody has that problem.

I will eventually get this power feed kit mounted, and I'm sure that this effort will pay off.

What do you guys do about accessing the ball oilers that are blocked by the power feed kit?


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## erikmannie (Sep 30, 2019)

The bracket supplied does not allow room for the tall dust cover, so I filed a relief in the dust cover. One could also use washers, but this would further limit travel in the y-axis (the limit switch cord limits travel here).


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## erikmannie (Sep 30, 2019)

I used the dust cover. I left about 1mm room between the bottom of the limit switch and the y-axis handwheel. The dust cover rubs up against the vise, so I can see why people don't use the dust cover.


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## erikmannie (Sep 30, 2019)

I finally got in a few hours of milling (fun!). After two hours, the power feed had changed position because I had not tightened the bolts enough. I carefully reinstalled the power feed with just enough torque to avoid slippage without cracking the cast aluminum brackets.


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## erikmannie (Sep 30, 2019)

I am still in contact with PM about returning this kit for a (partial) refund. If they won't let me, one of my first projects on the mill will be to redo all four of the brackets and make a shorter dust cover (which actually sounds like fun).

The cast aluminum brackets would work better if they were made of a more ductile material (e.g. aluminum plate). Tapping the saddle would also make things go more smoothly for the mounting of the limit switch. The motor is fine like it is.


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## WyoGreen (Sep 30, 2019)

Erik,
I didn't have to drill and tap any holes to mount the power feed to my PM30MV. After going back and looking closer at your pictures, I can see that the PM25 and PM30 have quite a few more differences than I figured. Anyway, the end plate I made completely replaced the stock end plate, so I was able to use the holes it used to mount my new end plate. I also put a bronze bushing in my end plate to better support the lead screw, so it has less slop and runs much smoother. I removed the ball oiler from the old end plate and put it in my new end plate. 
As far as the limit switch, my original stop had two side by side holes instead of the two up down holes you have, so the limit switch more or less bolted right up and did not interfere with the ball oilers. I did not use the dust cover either.


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## erikmannie (Oct 1, 2019)

WyoGreen said:


> Erik,
> I didn't have to drill and tap any holes to mount the power feed to my PM30MV. After going back and looking closer at your pictures, I can see that the PM25 and PM30 have quite a few more differences than I figured. Anyway, the end plate I made completely replaced the stock end plate, so I was able to use the holes it used to mount my new end plate. I also put a bronze bushing in my end plate to better support the lead screw, so it has less slop and runs much smoother. I removed the ball oiler from the old end plate and put it in my new end plate.
> As far as the limit switch, my original stop had two side by side holes instead of the two up down holes you have, so the limit switch more or less bolted right up and did not interfere with the ball oilers. I did not use the dust cover either.


You have a very nice mill in the PM-30V! I had forgotten that one could relocate the ball oilers. PM sells them in 6 and 8mm (picture below). Maybe I could do a one shot oiler system while I'm at it. I see a lot of info on those online.

It is starting to look like I will not be returning the kit. I modified so many parts, and PM asked for pictures. I sent pictures, but at this point the power feed kit is installed and I am using the mill a lot. Today will be about 5 hours of milling steel before I go to work.

I really do love the PM-25MV, the DRO and the motor in the power feed kit, so I would take that deal anyday.


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## erikmannie (Oct 2, 2019)

Everything worked out fine. After persevering in mounting the power feed kit, the effort finally paid off. Now I am using the mill with the power feed kit. PM did offer to allow me to return it, but I can see that I need a power feed.

     I relieved the dust cover a little more, and now it doesn’t get in the way of anything.


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## erikmannie (Oct 2, 2019)

Here it is installed with no current issues.


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## codexmas (Oct 2, 2019)

erikmannie said:


> Here it is installed with no current issues.



So you are liking it aside from the install issues? I read that it was a bit under powered and is always engaged making the hand-wheel a pain for manual?

Have any video of it in action?


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## erikmannie (Oct 2, 2019)

codexmas said:


> So you are liking it aside from the install issues? I read that it was a bit under powered and is always engaged making the hand-wheel a pain for manual?
> 
> Have any video of it in action?


Yes, the x-axis handwheel is a little difficult to turn, but I just call it a forearm workout.

     I will be very happy to make a video of the action. That will be up here within 24 hours.

     I am very happy with the mill. Precision Matthews has gone above and beyond in all aspects of customer service.


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## erikmannie (Oct 3, 2019)

Here is a video of my first project with this, my first milling machine:


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