My Precision Mathews PM1340GT Arrival

That is a great looking machine and a nice write-up, too! I hope you will do a similar one when your mill comes in. Its cool watching people get their new machines and seeing how they set them up...never seem to get tired of it. Congrats, dude!

Thank you. I will definitely do a similar write-up/review of my mill when it arrives.

Thats a great looking setup mike! Im gonna have to adopt some (all) of those ideas. I really like my PM1236, though I wish the overhang on the TS was on the HS end like all others Ive seen. Other than that, its perfect, other than the operator of course... Have fun, I think that machine will serve you well.

Richard

Thanks Richard. I appreciate that.

Yes I will have to steal/borrow that tool holder idea..............

I don't mind one bit. I just wish they were my ideas, I copied them from the internet as well. The toolholder rack looked like a nice addition.

Mike.
 
Thank you. I will definitely do a similar write-up/review of my mill when it arrives.

Do something cool with it. My setup is okay, but I'm better at copying other people's ideas when it comes to this sort of thing. I also wouldn't mind a little more detail when you have time/interest in sharing how you handled your chucks to arrive at your optimal orientation. Thanks!

-Ryan
 
OK, another quick update on my Precision Mathews PM1340GT arrival and review.

Last night my McMaster Carr order showed up. I had to order a few items for a paying job I have coming in so I thought I would throw a couple of small items of my own on the order to save freight. One thing that I don't like is the socket head capscrew for the carriage lock. I would rather have a dedicated handle there so I don't have to reach for an allen wrench or "T" handle to tighten it.

I ordered one of these adjustable handles for the carriage lock. McMaster Carr part # 6848K51 which measures M8x1.25x50MM. It is 2.5" from center of bolt to end of the ball on the handle, plenty long enough to tighten the carriage and lock it solid, yet small enough to merely bump it loose and in less than half a turn completely free the carriage so there is absolutely no drag on the bed.
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I also had to machine a small spacer to compensate for the depth of the recessed hole in the apron which allowed the head of the socket head capscrew to sit flush or slightly below the surface. I machined the spacer to a height of .250" so the handle would clear the apron surface yet still be low enough to allow the compound slide to swing over the handle with room to spare.

Machining the small spacer.
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Here is the spacer machined and installed on the bolt prior to installation.
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This is the original bolt for the carriage lock that I replaced.
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Handle installed along with spacer. Works great.
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After doing the little carriage lock mod, I decided it was time to change the lubrication in both the apron and the headstock gearbox. I have around 10 hours of actual run time on the lathe now so I wanted to get the break-in lube out and put fresh in.

This is the bolt that you remove to drain the lubrication from the apron.
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I didn't take any pictures of the drain plug on the headstock gearbox but it easy to spot as it is located just behind the gears under the removable side cover/gear cover. Pull the plug and lay a funnel or piece of cardboard under the gearbox to avoid getting oil all over your wiring and down the side of the lathe and allow it to drain into a suitable container. Once drained, apply some teflon to the plug and reinstall.

Now remove the small plastic plug on the top of the gearbox and add your new lubrication. Matt recommends ISO68/AW68 or Mobil DTE hydraulic oils in both the headstock and apron gearboxes. I used AW68 medium/heavy hydraulic oil from my local NAPA store. The headstock took 5-pints and the apron took 20 ounces to put the level in the middle of the sightglasses.

Overall, I think the PM1340GT is a fantastic lathe and I am more than pleased so far. It is an extremely accurate machine and a joy to operate. I have found myself able to take a light cut, mic the diameter of the part, dial in the amount to remove on the dial and turn to size very accurately. I have only made a few parts/projects thus far but I have been able to turn to size within .0005" of my target very easily and more importantly, I have been able to repeat those dimensions.

As far as the overall lathe fit, finish and feel, it is just like it states on the QMT website. It is a very high quality lathe with special attention paid to the overall fit and finish. The gearbox is extremely quiet for a geared head lathe. The apron handles and screws are very smooth and fluid in their movements and the dials are spot on accurate. The gear change handles/controls on the headstock are loosening up slightly after some use although mine were never very hard to turn. The gears change very easily and the detents are crisp and positive when switching from one gear to another. The knobs to change between the feedrod and leadscrew as well as the direction of the feedrod/leadscrew are the same way, very crisp and positive when changing. On occasion you will have to move the chuck back and forth a small amount to get the gears to mesh and allow them to change but that is completely normal on a geared head lathe.

I looked for many months at old used machines before realizing that I could not find what I was looking for. I opted to look at new import machines as currently if you want a new lathe, an import is your only real option as none are currently being manufactured in the United States, sad but true. We have gone from a country of innovative creators to a county of consumers but that is another story. I caught a lot of negativity when I started looking at import machinery but based on the ones that I looked at and was able to put my hands on I feel that the PM1340GT is about as good as anything in this size lathe that is currently available, possibly even in a class of its' own.

I will say that Matt @ Quality Machine Tools has been great to deal with as far as answering any questions, both prior to purchasing the equipment and after putting down the deposit and even after full payment. He has been quick to respond to emails and if he didn't answer the telephone when I called, I left a message and he ALWAYS returned my calls.

All that said, I could not feel good about giving an honest review without mentioning the long wait time. If you are looking at purchasing this lathe from QMT, be prepared for an extended wait time as he only gets a few shipments of these Taiwanese machines per year and most are pre-sold at the time the shipment leaves Taiwan. He seldom has more than a couple that aren't spoken for when the shipment arrives to him in PA. He gets many more deliveries of the Chinese machines than the Taiwanese so be prepared. My 8-10 week lead time at time of ordering turned into 22 weeks before arrival.

I hope this review was helpful and provided useful information to anyone who owns one of these lathes or is looking at purchasing one.

I will also be conducting a similar review of my Precision Mathews PM935TV when it arrives. Again, it too has been a long wait. I hope it is every bit the machine that the PM1340Gt is.

Mike.
 
Nice review Mike, well done.

Now I'm looking forward to you getting your mill almost as much as you are so I can read your review on that machine.
 
Do something cool with it. My setup is okay, but I'm better at copying other people's ideas when it comes to this sort of thing. I also wouldn't mind a little more detail when you have time/interest in sharing how you handled your chucks to arrive at your optimal orientation. Thanks!

-Ryan

Sorry Ryan, I had overlooked your question about the chucks.

First and foremost, I removed the 3-jaw chuck and cleaned all of the cosmoline from both it and the spindle itself. Be especially vigilant in cleaning the taper on the spindle and the corresponding taper inside the back of the backing plate. The taper is where the chuck actually rides, not the camlocks. Be certain to place a 2x4 or some other sacrificial material across the bed ways of the lathe. This is just in case you drop the chuck, it doesn't damage your ways on the lathe.

I tried the chucks in each of the three positions on the D1-4 camlock spindle. I chose the position with the least amount of runout to start with. The 3-jaw that came on the lathe was already in the position with the least amount of runout. Clamp a good straight piece of steel, preferably some drill rod in the chuck and use a dial indicator to test the runout. Place the dial indicator fairly close to the chuck to start with as the chuck is what you are actually measure first.

Also, be aware that "how" you mount the chuck on the camlock will have an affect on the runout and especially the repeatability when removing/reinstalling chucks onto the spindle. I have found that to be consistent I set the chuck into the camlocks and push it onto the spindle as far as possible and as squarely as possible to mate up against the spindle taper. Then with the other hand I turn one of the camlocks until I "just barely" feel a slight amount of resistance. Meaning the camlock as barely touched the post on the backing plate. I then turn to the next camlock and repeat. I do this with all three so they each have the same amount of "preload" on the camlocks before completely tightening a single one.

I then follow up starting with the same one I originally started with and tighten the camlocks until the mark on the cam is between the two marks on the spindle. I then run around one more time and check by feel the consistency of the camlocks. Now chuck up your test bar/drill rod and once you get the position with the least amount of runout mark the chuck and the spindle so you can repeat it. I mounted/re-mounted my chucks multiple time until I found a procedure that netted me the best accuracy and I could repeat it time and time again.

It really takes longer to explain that to actually perform this task so don't worry about how long it will take between chuck changes. Once you have the chucks cleaned and orientated on the spindle, if you need to switch over from one chuck to another it is a matter of seconds rather than minutes. Also, it is a good idea to check this once in a while, especially if you are needing to turn something that is imperative that it is absolutely accurate, then just throw a test bar in and a dial indicator on for verification.

For the Gator 6-jaw and many other chucks that have the set-tru ability, you go through the same process to find the most accurate position, however, you then have the ability to fine tune the chuck onto the backing plate and therefore the spindle centerline by turning one of four separate adjusters that position the chuck similar to setting up a four-jaw. Just use a good dial indicator and push away from the high readings and move towards the low reading until you are happy with the runout.

I hope that was helpful and what you were asking for.

Mike.
 
Nice review Mike, well done.

Now I'm looking forward to you getting your mill almost as much as you are so I can read your review on that machine.

Thanks Mac, I appreciate the feedback.

I found a lot of comments about the PM1340GT when I was looking but nothing quite as in depth as what I was looking for. I hope this is beneficial to anyone else looking at this particular lathe.

Mike.
 
Sorry Ryan, I had overlooked your question about the chucks.

I hope that was helpful and what you were asking for.

Mike.

Yeah, thanks. I would have been satisfied with with "Tighten the camlocks progressively and check runout in each of the three possible mounting positions." Having only owned a threaded spindle, I wasn't sure if you meant you took them apart in any way when you went through the process, or did anything more involved. Makes perfect sense to check this way.

I will say that I'm now rather curious about the accuracy of my Atlas lathe as I've never checked it other than with a machinist's level. In case anyone cares to read up a bit, Harold Hall's book "Metal Lathe for Home Machinists" has a section about leveling and aligning the tailstock much like you did that makes a lot more sense to me now. Tubalcain also has a few videos about it.

I know I've said this before, but you are going to be happy with your choice to get the 935. How long is that supposed to take?

-Ryan
 
Yeah, thanks. I would have been satisfied with with "Tighten the camlocks progressively and check runout in each of the three possible mounting positions." Having only owned a threaded spindle, I wasn't sure if you meant you took them apart in any way when you went through the process, or did anything more involved. Makes perfect sense to check this way.

I will say that I'm now rather curious about the accuracy of my Atlas lathe as I've never checked it other than with a machinist's level. In case anyone cares to read up a bit, Harold Hall's book "Metal Lathe for Home Machinists" has a section about leveling and aligning the tailstock much like you did that makes a lot more sense to me now. Tubalcain also has a few videos about it.

I know I've said this before, but you are going to be happy with your choice to get the 935. How long is that supposed to take?

-Ryan

Glad that helped to explain it Ryan. On my Smithy lathe that I had prior, my chuck had some "catches" or rough spots in it upon arrival. I took it apart and deburred the scroll, re-lubed and re-assembled it and was quite happy with it afterwards. I was completely ready to have to do that again with this one, however, it is a nice quality chuck right from the get go. Just cleaned the cosmoline off and it was ready to use, I honestly wasn't expecting that.

As for my milling machine, I received an email from Matt on Saturday afternoon stating that they are just finishing up the remainder of the 935's and it will be shipped this week for sure. So far being Wednesday (half the week gone) I have not seen an email with a tracking number, I was kind of hoping to see it next week when I received the email from Matt. Now not so sure.

Mike.
 
OK, I ran into an issue last night that I thought would be worth mentioning. I did my first threading on the PM1340GT last night. I was making some hold down bolts to mount my GMT 5" vise to my PM935TV when it shows up. I could have made the 1/2-13 threads with a die but hey, that is what I bought the lathe for, right.

The threading dial on the PM1340GT is different than I am used to. The threading dials I am used to have eight (8) markings, four of them are numbered 1-4 every 90 degrees on the dial. In between the numbered markings have been a line at 45 degrees. Usually any number or mark can be engaged for even numbered thread cutting and only using the numbered positions (every 90 degrees) for odd numbered threads.

The threading dial on the PM1340GT shows eight positions and each being numbered 1-8.
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By looking at the threading dial chart is shows for 13 TPI you should engage on numbers 1-4.
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At first I thought that looked a little suspicious but then again didn't give it is second thought. I cut my escape groove for the threading tool, marked the area to be threaded and made a scratch pass. I checked the scratch pass with my thread gauge and everything looked good. I advanced my compound slide .010" and as the number 1 came around I engaged the half nut. Same position as the scratch pass. I didn't plan it that way it was just the first number coming around as I was ready to start the first cut. I advanced another .010" with the compound and this time number 4 was coming around so I engaged the half nut, and that is where it went to hell. It cut right across the first pass.

I double checked the dial, chart and even resorted to getting the manual out (which is not the greatest text) but thought may as well be thorough. The manual even explains it similar to the style of dial I have used on other lathes. Here is the quote from the manual: "To cut threads of an even number per inch. Close the leadscrew nut as any line on the dial passes the datum mark. To cut threads of an odd numbers per inch. Close the leadscrew nut at any numbered line." I won't quote the part about fractional threads as that is not relevant to this.

I decided to give it another try but break the threading dial up into quadrants like I am used to which would be every 90-degrees. This equated to engaging the half nut at positions 1, 3, 5 or 7. Imagining that the numbers 2, 4, 6 and 8 would be the reference marks located between each of the four numbers. Voila, works perfect. I used a test piece of rod and engaged in the odd numbers and the thread turned out great. I then chose to test a 10 TPI and engaged on any number, that too worked great.

So just for clarification, when threading on the PM1340GT lathe for even numbers you can engage the halfnut on ANY number 1-8 and be safe. If you are cutting an odd number of threads ONLY engage the halfnut on numbers 1, 3, 5 or 7 (odd numbers).

Here are the two studs after completing my threading. The one not in the chuck is my first one that I encounted the issue with. It was early enough in the threading that I didn't want to trash the part so I completed it and it only appears that the first thread got buggered up.
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Nut threaded right on nice and smooth.
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I hope that helps to clear up any confusion just in case anyone else experiences a similar issue when threading.

On a side note, I also swing my threading dial out of the way so it is not engaged with the leadscrew when not cutting threads. My son informed me a few years ago when he took a machining course at the local university that the instructor asked that the students do this and I thought it was a good idea to not have the brass threading dial gear running along the leadscrew when it is not needed. It only takes a second to loosen the socket head cap screw and swing it back into position when you are going to thread so it really is not an inconvenience.
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One other thing I forgot to show earlier as a modification/custom touch. I cut a 1-1/16" combination wrench and TIG welded a 1.5" steel ball to the end of it. I use this for the nut on top of the Dorian toolpost and added a stud to hang it on within easy reach on the backsplash of the lathe. The steel ball fits nicely into the palm of my hand and is very comfortable when loosening the toolpost nut.
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Here is where I hang it.
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I have enjoyed reviewing this lathe and hope that the information has been useful.

Mike.
 
Also thought I would post up the formulas for my threading. I am curious as to whether or not they differ from others or not.

First off I start with a major diameter of .005" less than the nominal diameter of the bolt/fastener. Then for a relief groove I use .613 divided by number of threads per inch and add .0025" or (.613/TPI)+.0025".

For depth of thread using the compound I us .713 divided by number of threads per inch and then move the crossfeed in .001" to .002" for cleanup cut to form on both edges of the thread. Expressed as (.713/TPI) plus .001"/.002" crossfeed.

One area I find a lot of controversy over is the width of the flat at the end of the cutting tool. I have been using the formula of 1/8 of the pitch or (Pitch/8) but I cannot remember where I picked that up from and have been unable to confirm that.

An example using the formulas for a 1/2-13 thread would be as follows:
Relief groove .0497" or .050" depth.
Outside diameter of .495". Nominal diameter minus .005", or .500"-.005"= .495"
Compound feed of .055", (.713/13)
Crossfeed cleanup of .001"-.002"

This is with a 60 degree ground cutting tool with a .0096' or .010" flat on the end, or slight radius.

Also one thing I have to get my head around on this machine is when feeding with the crossfeed dial I need to use 1/2 the dial reading because I want total cross slide movement not diameter removed numbers.

I was going to double check my numbers by using the 3-wire method last night but a client came by to drop off a bike and I honestly forgot until today. The nut fit and I just simply forgot that I wanted to check via the 3-wire method.

Mike.
 
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