PM-833TV CNC Conversion Accuracy?

[7milesup]

Yep, totally understand that. I just have to draw the line somewhere. That ACRA is 1000lbs more....There is no doubt it would probably be better, but I'm not sure I can manage that weight in my shop. The PM-935 is already pushing it. My worry is this new hobby is going to end up costing me way more than I ever expected. I have been toying with the idea of moving now....so I can build a real shop. LOL.

I agree with @Tipton1965 . I followed the same route that he did with my mill journey. I also owned a PM833T and although it was an ok mill, there were a few issues. Mine had a couple of gibs that were not 100% great and adjusting them resulted in not having a jib adjusting screw on one end. Sure, a shim would fix this, but why on a new machine when they say it is a super precision machine? A call to PM resulted in them saying that the gibs had to be matched to the machine and such. I then asked that if that was the case, why weren't my gibs matched to my machine?
I ended up finding a very nice Sharp mill and then sold my PM833T. The Sharp is 3.5 times heavier than the 833, but that extra weight makes it a dream to use. Solid and precise is how I would describe it. I currently have mine on a pallet that I made when I moved it into my shop, which allows me to move it with my pallet jack should I need to.

 

[Beantown]

You can move it around with a simple pallet jack no problem. View attachment 472091

Interesting. When I was looking at shipping, it said that liftgate service was not available and I would need forklift service?!

 

[matthewsx]

Interesting. When I was looking at shipping, it said that liftgate service was not available and I would need forklift service?!

Yes, that’s because it exceeds the capacity of most liftgates. Moving it around the shop with a palate jack is a different thing.

I would have bought a full size mill several times before I got my baby Bridgeport if I could have fit it into my shop. I used a palate jack and drop deck trailer to bring it home but have since built a stand with leveling casters. Can easily move it around the shop if needed.

It’s worth the extra effort to get a bigger machine, especially if the price is comparable.

John

 

[davidpbest]

I upgraded from the original Rong Fu 45 to the PM-935. I wish now I had gotten the ACRA LCM 9x42. The PM-935 is a nice baby knee mill but it turned out to be a lot less rigid than the RF-45 benchtop mill.

 

[Beantown]

I upgraded from the original Rong Fu 45 to the PM-935. I wish now I had gotten the ACRA LCM 9x42. The PM-935 is a nice baby knee mill but it turned out to be a lot less rigid than the RF-45 benchtop mill.

Well hello, sir! Hope you have been well. I see you upgraded to "Commercial Status" now?

The lack of rigidity is quite concerning given the price. Now, I recall you mentioning that when we were talking about my lathe purchase. I requested a quote from ACRA on the LCM-42. It appears to be about $3000 more than the PM-935TV if I go on Penn. Tool's pricing. The extra cost, shipping weight, and overall size might be too much for me to justify....Although I'm no billionaire, the size is my biggest worry. Same reason I had to stop at the PM-1440GT instead of getting a bigger machine. I already have 100lbs of junk in a 10lb bag.....and growing. If I was honest with myself or if you asked my wife, the 935 is probably too big as it is.

I read your comparison on the pros\cons of the different lathe types. The PM-935 seems like it's just a bad design to use the same giant milling head on a smaller frame. But everyone keeps telling me to get the 935 over the 833 for the extra rigidity. Your write up a discussed ridity in reference to weight. The PM-833TV is about 300lbs heavier than the RF-45, so do you think the 833 would be more rigid than the 935 as well? Or is there something special about the RF-45 that makes it extra rigid?

I wish I could just have my cake and eat it too...

 

[Tipton1965]

Interesting. When I was looking at shipping, it said that liftgate service was not available and I would need forklift service?!

Yeah, I had my ACRA shipped to a local crane outfit. They used a large forklift and loaded my mill on their truck. They also loaded their forklift on the same truck. They drove to my shop and unloaded. I think I paid $400.00 for the service which I thought was pretty good.

 

[Beantown]

Yeah, I had my ACRA shipped to a local crane outfit. They used a large forklift and loaded my mill on their truck. They also loaded their forklift on the same ruck. They drove to my shop and unloaded. I think I paid $400.00 for the service which I thought was pretty good.


View attachment 472125

Yea, I'd say that is a pretty good deal! Hmmmmm if I can figure out the space situation, I'll think pretty hard about the ACRA. I'm sure I could find someone around here that could do it, so I won't let that keep sway my decision. The more I read about the PM-833 the farther it is off the table. I might have to settle for the PM-935 due to space.

Do you know the total width of the ACRA when you consider the full travel of the table? ACRA's website doesn't seem to list that. It just says 57.8" and that doesn't make sense. I'm thinking that is just the width of the table including the handles in the center position.

 

[davidpbest]

Well hello, sir! Hope you have been well. I see you upgraded to "Commercial Status" now?

The lack of rigidity is quite concerning given the price. Now, I recall you mentioning that when we were talking about my lathe purchase. I requested a quote from ACRA on the LCM-42. It appears to be about $3000 more than the PM-935TV if I go on Penn. Tool's pricing. The extra cost, shipping weight, and overall size might be too much for me to justify....Although I'm no billionaire, the size is my biggest worry. Same reason I had to stop at the PM-1440GT instead of getting a bigger machine. I already have 100lbs of junk in a 10lb bag.....and growing. If I was honest with myself or if you asked my wife, the 935 is probably too big as it is.

I read your comparison on the pros\cons of the different lathe types. The PM-935 seems like it's just a bad design to use the same giant milling head on a smaller frame. But everyone keeps telling me to get the 935 over the 833 for the extra rigidity. Your write up a discussed ridity in reference to weight. The PM-833TV is about 300lbs heavier than the RF-45, so do you think the 833 would be more rigid than the 935 as well? Or is there something special about the RF-45 that makes it extra rigid?

I wish I could just have my cake and eat it too...

I've had a commercial account for a while now - not that I'm trying to do serious business on this forum, but it's a requirement if I want to include a link to my book on indexable tooling in my signature line below. It does provide me with my own sub-forum, which I use occasionally to post write-ups that I think might be useful to those getting started. I just renewed my membership and "Presto !!" my status is now displayed in brilliant red. I now know what Hester Prynne must have felt like in Hawthorn's novel. LOL

IMO, $3000 isn't much of a premium over the 935 to get into an ACRA LCM-42. I'm attaching the brochure for the ACRA mills which may be of help in your evaluation. The dimension are provided on page 2 - take note of their more rigid head mounting claim on that same page. It's not that much different in terms of shop space from the 935, except for height.

I can't comment on your question about PM-833 versus PM-935 rigidity as I haven't done any type of testing. You can see plenty of details about my PM-935 journey if you visit the "publications" section of my new web site, and click through to my Flickr build logs. Lot's of people love their 935, and I've learned to deal with its rigidity limitations. James Clough (Clough42 on YouTube) seems to be in love with his 935, and he's pretty fussy about things, although he doesn't do any truly demanding work with it that I've seen, and his point of comparison is a Grizzly 0704 baby benchtop mill. But the ACRA is in a different league, not only in rigidity, but fit and finish as well.

 

[Beantown]

I've had a commercial account for a while now - not that I'm trying to do serious business on this forum, but it's a requirement if I want to include a link to my book on indexable tooling in my signature line below. It does provide me with my own sub-forum, which I use occasionally to post write-ups that I think might be useful to those getting started. I just renewed my membership and "Presto !!" my status is now displayed in brilliant red. I now know what Hester Prynne must have felt like in Hawthorn's novel. LOL

Ah! That makes sense! I'll definitely check out your posts in your sub-forum soon!

IMO, $3000 isn't much of a premium over the 935 to get into an ACRA LCM-42. I'm attaching the brochure for the ACRA mills which may be of help in your evaluation. The dimension are provided on page 2 - take note of their more rigid head mounting claim on that same page. It's not that much different in terms of shop space from the 935, except for height.

Excellent, thank you. If my assumptions are correct, the LCM-42 is about 12" wider and about 25" deeper in footprint (if using the full range of motion). How often does one move the head in and out? I have yet to see anyone in a video do that. I have a reasonably accurate 2D CAD drawing of my shop space and even with the 935 I'm limited in motion..... handles will be bumping into other machines or a wall in full motion. I submitted a quote to ACRA and while I wait I'll play around more with drawing. I'm even toying with the idea of getting rid of some of my woodworking tools that I don't use much. Since I have never thrown a full sheet on my CNC router I am almost tempted to convert it down to a 4x5 instead of a 4x8, but that feels like crazy talk. I can definitely see that this machine would be the way to go if it will fit. More to come on that!

I can't comment on your question about PM-833 versus PM-935 rigidity as I haven't done any type of testing. You can see plenty of details about my PM-935 journey if you visit the "publications" section of my new web site, and click through to my Flickr build logs. Lot's of people love their 935, and I've learned to deal with its rigidity limitations. James Clough (Clough42 on YouTube) seems to be in love with his 935, and he's pretty fussy about things, although he doesn't do any truly demanding work with it that I've seen, and his point of comparison is a Grizzly 0704 baby benchtop mill. But the ACRA is in a different league, not only in rigidity, but fit and finish as well.

I have seen most of the Clough42 videos and even in a recent video he raved about his. It sounded like space was his primary concern as well. It does seem like the PM-935 is even overkill for the kind of projects her works on and I think I would fall into a similar situation. Oddly enough, I think he lives pretty close to me. Nevertheless, like the PM-1440GT purchase, the PM-935 should be more than I would need or justify. It will take me a lifetime to catch up to most of the people on this forum, so there is a good possibility I wouldn't even notice the issues your have run into based on the level of work and tooling I have seen you share in other posts. However, if I can get an even better machine for a comparable price (and make it fit) I won't hesitate.

Believe it or not, I started this journey set on purchasing MUCH smaller machines. In fact, I was planning on purchasing the same machines that Quinn from Blondihacks uses and it spiraled out of control! I have already spent nearly x2 as much on tooling and measuring equipment alone than both of the original machines I was looking at cost. It's a sickness. I'm like a broken record, but I'm very grateful my wife is such a saint!

 

[7milesup]

Believe it or not, I started this journey set on purchasing MUCH smaller machines. I

Yeah, haven't we all? When I started, I purchased a craptastic Harbor Freight mini-mill from a friend. After a few months, I knew it was junk but liked the hobby. Then the 833T. Now the Sharp. I apparently have a sickness...
One thing I would like to mention is resale. I would suspect you will recover much more of your money with a knee mill than a benchtop mill should you decide to bail on this hobby.