Becoming hobby machinist in the near future.

[Rhizome]

Maxi Torque-Rite makes a PDB version for the PM-833T/TV?

I am using a spline wrench on my PM-833T and the hex corner of the draw bar interferes with the wrench at certain angles as you guys discussed. It is annoying sometimes, so I think eventually I will make a new one, mill the draw bar hex head smaller or install a PDB.

 

[Rodneyk]

Maxi Torque-Rite makes a PDB version for the PM-833T/TV?

I am using a spline wrench on my PM-833T and the hex corner of the draw bar interferes with the wrench at certain angles as you guys discussed. It is annoying sometimes, so I think eventually I will make a new one, mill the draw bar hex head smaller or install a PDB.

Just a guess but from what I can tell it would be a custom system, not something they intended for their "packaged" models. And since it looks like there are several unique versions of the PM833TVV now you would need to make some adapter for your machine.

 

[davidpbest]

Just a guess but from what I can tell it would be a custom system, not something they intended for their "packaged" models. And since it looks like there are several unique versions of the PM833TVV now you would need to make some adapter for your machine.

I think the first decision is whether to use the TTS system or stick with R8. They each require a different type of power drawbar setup. If you want to go down that hole, we can.

But assuming and R8 collets and arbors, the the Torque Right would be a good solution. The manufacturer of Maxi TorqueRite makes custom versions of their PDB all the time. I have a custom install on my PM-935. They will need a few dimensions to figure the right dimension of the drawbar itself. And given the stick-out of that splined spindle end, the head unit will need to be mounted in an elevated position. The same was true on my PM-935. You can see in the photo below that it's elevated on stand-offs provided by the manufacturer. In the case of the 833, it looks like the top of the mill head is a sheet metal cover. Depending on the thickness of that sheet metal you might be able to use stand-offs like shown below, or if it were mine, I'd make a custom riser ring out of 6061 aluminum which would take about an hour between the lathe and mill time to make.

The drawbar on the Maxi TorqueRite has a splined head - which is one of the ways they get the amount of torque on the drawbar that they advertise. This is the kind of spec sheet you fill out and send in, and they make the drawbar to fit your machine.

 

[Tipton1965]

Good info guys. I too need to come up with something clever to tighten the draw bar on my 833TV.

 

[Rodneyk]

Good info guys. I too need to come up with something clever to tighten the draw bar on my 833TV.

What does you machine look like? Having different versions of the same model must be hard for the QMT/PM guys to support. I guess I got lucky with my version in that at least I can easily get a hold on the machine.

Currently I have the machine

• Assembled in its hew home
• Leveled the bed
  • surprisingly I had leveled the stand across the mounting pads,
  • then move the stand 6" to the left
  • and totally messed up the level (but figured I had to level the bed anyway so I continued)
  • then when I went to level the bed it was spot on already with just the feet making positive contact with the ground
• mounted the DRO display
• mounted the handles (which will come off to put on the power feed in the next step, but I needed some way to veryify the DRO is happy
• The lash on the table is way more than I expected (5 ticks which are 0.02" if memory serves me so 0.1" from when the handled it reversed to when it moves the table in the reverse direction. Really glad I got the DRO now. Later I will look into if I can reduce the lash.
• Added 220V plug end.
  • Triple checked the wiring and for any shorts.
  • Cleared the machine of any tools or foreign objects.
  • Plugged in the machine to the outlet, heard cooling fan come on and no evil sparks of doom emitted from anywhere.
• Tested that the spindle turned at a few speeds.
  

 

[Tipton1965]

What does you machine look like? Having different versions of the same model must be hard for the QMT/PM guys to support. I guess I got lucky with my version in that at least I can easily get a hold on the machine.

I posted this photo earlier in your thread but will post it again. It's my machine next to yours. I believe the only difference is the upper sheet metal cover. Mine bumps up in front of the motor where as yours continues flat to reveal the shaft.

 

[Rodneyk]

I posted this photo earlier in your thread but will post it again. It's my machine next to yours. I believe the only difference is the upper sheet metal cover. Mine bumps up in front of the motor where as yours continues flat to reveal the shaft.

Yeah, I would bet that it is only a cover and faceplate difference. I imagine they were in the middle of changing the design between the machines, and part of their order was your design because they were already built and part was mine. My SN is 20059, assuming sn are in order I would bet yours comes before mine.

Somewhere on this forum I saw another person who had the issue you are seeing. I think he made a tool that was like a wrench with 2 opposing right angles that fit into the hole. I read the post about a day after ordering the mill and I was worried the entire time that I would need to do something like that (and I don't have any welding equipment in my shop yet) I guess I could 3d print something that would work (I have printed other tools that had to be much stronger than that. Maybe after I finish setting up mine I will see if I can come up with something. If you have time post some measurements. For example how large is the hole on the top of your machine where the tool needs to go. I assume the drawbar measurements will be the same as my machine

 

[Tipton1965]

Yeah, I would bet that it is only a cover and faceplate difference. I imagine they were in the middle of changing the design between the machines, and part of their order was your design because they were already built and part was mine. My SN is 20059, assuming sn are in order I would bet yours comes before mine.

Somewhere on this forum I saw another person who had the issue you are seeing. I think he made a tool that was like a wrench with 2 opposing right angles that fit into the hole. I read the post about a day after ordering the mill and I was worried the entire time that I would need to do something like that (and I don't have any welding equipment in my shop yet) I guess I could 3d print something that would work (I have printed other tools that had to be much stronger than that. Maybe after I finish setting up mine I will see if I can come up with something. If you have time post some measurements. For example how large is the hole on the top of your machine where the tool needs to go. I assume the drawbar measurements will be the same as my machine

My SN is 20004 so you may be right on that. The hole in the top of the sheet metal cover measures 1.950". Here's a few pics of other measurements. The one measurement is the overall length of the draw bar including the Hex top portion.

 

[Rhizome]

I think the first decision is whether to use the TSS system or stick with R8. They each require a different type of power drawbar setup. If you want to go down that hole, we can.

David, what does the acronym TSS stand for? I searched, but could not come up with a definitive answer.

The PM-833T's gear box does not have that sheet metal extension on top. I suppose a PDB from Maxi TorqueRite will bolt right onto the cast iron. Here is a picture for comparison to the TV version. That yellow-cap nut may get in the way though.

 

[davidpbest]

Sorry if I sent you on a wild goose chase, but the term is TTS not TSS. TTS is the Tormach Tool System - it was invented by Tormach and is essentially a quick-change tool holding system. It facilitates use of an automatic tool changer and also makes it possible for any specific tool to register to the same dimensional stick-out from the spindle when the tool is mounted. With this system a TTS collet is installed in the spindle - it's R8 at the back end, and has a precision cylindrical hole at the other. Each tool (end mill, drill chuck, saw arbor, face mill, whatever) is installed into a dedicated TTS compatiable tool holder that fits into the cylindrical hole in the TTS collet. When the drawbar is pulled up, the collet squeezes around the outside of the tool holder and also pulls the tool holder up to register consistently in the vertical direction. With this setup, tools can be changed by simply pushing down on the TTS collet, freeing the tool holder, rather than having to completely unwind the drawbar threads in the R8 collet or R8 arbor.

This is the TTS R8 collet. It's mounted in the conventional manner with a drawbar threading into the end. But it can be set up in a manner that a power drawbar only has to push down on the collet about 1/4" to release the tool.

Here are typical tool holders - end mill and drill chuck arbor:

Ultimately you end up with all your mill tools mounted in dedicated TTS tool holders like this:

A power drawbar for this system does not have to rotate the drawbar - it only needs to push down on it. So a TTS PDB is typically built using Bellville washer as the high tension springs that keep the collet pullled up and closed on the TTS tool holder until an actuator (typically pneumatic) pushes down on the drawbar to release the tool.

A conventional R8 power drawbar is typically built using the guts of a pneumatic impact wrench to unscrew the drawbar completely from whatever tool is currently in the spindle. The Maxi TorqueRite system is one commercially available system that functions in this manner, but there are others (Kurt makes one) and a lot of people build their own.

The TTS system is quicker to use, but the force holding the tool in the collet is limited by the strength of the springs pulling up on the collet. In aggressive milling operations, some users have experienced tool slippage or even tool pull-out with the TTS system. Still many owners of mills in the 833 class of machine use the TTS system successfully. I use another style system called the Royal EasyChange system that doesn't require any type of power drawbar, but that's another subject completely.

Here are some resources that might help wrapping your head around all this.

This video gives a good overview of a TTS power drawbar build.

Priest Tools makes after-market TTS power drawbar system. Here's an example of someone adapting the Priest to an 833.

This video goes over a typical impact wrench implementation of an R8 PDB.

Here is another R8 PDB implementation.

Of all the R8 PDB DIY implementations I've seen, this design is what I would copy if I made my own (skip to 34.40 in the timeline).

Hope this helps.