I need to do this. I have been doing mine up pretty loose because that little 8mm square just feels so flimsy. Great idea.

An unexpected benefit of filming machining operations for KZfaq has been the chance to review and discover what went wrong and when. I was milling two identical parts, the first one was great, but something went awry on the second, and the movable jaw plate was cut. Reviewing the video, the tool pulls out during an early cut. Tormach recommends 30 ft-lbs for on the TTS for heavy cuts. I was far from it. It's great to know the cause, because I'd previously had a similar problem, which was then unexplained. Always something to learn, right? :)

Pull-out sucks. We used to sell worm-screw style holders for bigger machines, for this reason. They hold on to the tool amazingly well. No good for our little mills. Do you have any issues getting the holder out again after tightening it up to full torque?

With the standard drawbar, I a quick tap of a wrench knocks the tool out. With the new drawbar, torqued to 30 ft.lbs., a takes a bit more, but a good drawbar wrench-hammer combo should have enough mass. Wouldn't always need to torque it so much for small tools or light passes. Below are two links related to the Tormach TTS and drawbar torquing. Hopefully the links show up. www.tormach.com/blog/best-practices-for-preventing-collet-slip/ www.tormach.com/uploads/163/ED10067_ToolHolding_Whitepaper_1010A-pdf.html

Thanks Kent. I'll check them out.

Hi Robert, that's as complementary as comments come, thank you very much. I hope the purchase serves you well and that you can avoid the various mistakes that I've made :) Have a wonderful weekend!

Thank you. If it helps, today, I would reduce waste by make the drawbar as two pieces and weld or pin them together. Also, the hex head was reduced to 17mm to match the nuts in the clamping kit. Best wishes

@@kentvandervelden Two pieces with welding will indeed reduce waste. My metric mill I use a short style ring wrench ratchet low profile for now. You could try it with your 17mm hex head.

Thank the for the recommendation. I bought ratcheting wrenches to dedicate to the lathe and mill. They're going to work well. Also, picked up square drive sockets for tightening lathe chucks. Look promising and not going to leave those in by accident.

Wonderful explanation of the two, thank you! I need to think about how to contain coolant on the lathe, and not have it thrown off onto all the neighboring surfaces.

For 1/4" endmills probably not, and for 1/8" certainly not. Probably necessary for 1/2" end mills with a large radial and axial length of cut and a convenience for other sizes. I resized the hex to be the same size (17mm) as the nuts used on my clamping set. The ejection cup always required several turns more than what's necessary for loosing and tapping out the tool.

Hi Jay, thank you. With the little 8mm wrench I was way under the 30 ft-lbs that Tormach recommends (1.) Using a reasonable size wrench now, hitting near 30ft-lbs is no problem, and that's aided by adding a spindle lock. The Industrial Hobbies mill I had used end mill holders, and I liked them. People say that TTS is more reliable in extension length, but I had pretty good luck with the end mill holders. Do you do a Z touch off with each? Do you dislike using the hammer because of impact on the bearings? With the new drawbar and TTS, only a half turn is needed with a fairly light tap. I've not given thought to self ejection, but perhaps one could make an adapter to increase the diameter of the threads at the top of the drawbar. Sort of a thick-washer like part with inside and outside threads (and tightened with a spanner) then make a new cap to fit the adapter. I did consider making a power drawbar and got an air over hydraulic power unit (2), but abandon the idea simply because the mill project was becoming more of the focus instead of a tool to get stuff done :) I don't know if it is practical, but I would consider using a lever driven cam to collapse belleville washers on the drawbar. A poorman's manual-power drawbar. Starting again, I would not turn the drawbar from a single piece, but instead use two different diameters, and pin them together. My approach in the video was pretty wasteful of material and time. 1 www.tormach.com/uploads/163/ED10067_ToolHolding_Whitepaper_1010A-pdf.html 2 drive.google.com/open?id=12vmSLsWVtk3ec8ywOIhveUgDTDzKgcuXcQ

_Do you do a Z touch off with each?_ I just started using end mill holders in the middle of my faceplate project, and I've been doing a Z touch off every time since the set screw doesn't force the end mill to precisely the same height every time. So far I haven't had anything so repetitive that maintaining a Z reference from one tool to the next would help much, but if it came up I might consider getting duplicate holders of the most common sizes so I could just swap them. I might be more inclined to do that after I convert the mill for CNC. _Do you dislike using the hammer because of impact on the bearings?_ The PM25 manual talks about hammering on the drawbar and I did that at first, until I discovered I could just back it out to eject the collet. I'm concerned about repeated impact to the bearings and also possibly shifting the mill out of alignment over time, probably not a legitimate worry on either count but I still try not to hit tools if I don't have to.

@@kentvandervelden What do you mean by pin them together? Do you mean weld?

@@mattmagilke2433 Assemble the parts, drill, and drive a pin into the hole. Thank you

Happy New Year Patrick, nice motorcycle! It's certainly possible to torque the original drawbar with a smaller head. I was concerned that there might not be possible too many times. You know that feeling when you're tightening a screw, right before it strips out? That's what I was noticing. I'll post a video today about goof-ups of 2016, and at least a couple were from improper drawbar torque combined with TTS holders combined with relatively heavy milling. If using traditional setscrew R8 end mill holders or small end mills the original drawbar is likely fine. Best wishes, Kent

Thank you Gavin for your support and suggestion! I followed your advice in Fusion360 and it looks great. For facing, I also set the pass direction to 90-deg and the bottom-height to the contour. Combine the facing operation with a 1.5" face mill and the flats would look great and be cut fast. I didn't immediately see how to use contour, but it's multiple roughing passes that I was missing. I hope you received my Hello via the Autodesk Fusion360 guys who were at IMTS in Chicago. One guy said he works with you regularly and was going to be talking with you the following week. It's such an amazing and small world :)

Ha. I haven't had the "hello" passed on yet. I wonder who that was... I'll be asking all of my Fusion contacts now! :) With 2D contour, I think you can also use multiple finishing passes to achieve the same thing.

I looked through the stack of cards from IMTS but I'm sure the Autodesk guys were out. The man who knew you has Asian features and has group meetings that you are involved with. Sorry, that's that the most vague description, but that's the best I have. I tried to convince them to replace the Solidworks hat I was wearing with one of the nice sweatshirts but they were not budging :)

Not sure who that is, but I'll figure it out eventually. Haha.

Ah! His first name is Matt. Hope that helps. (40 year old slow memory :)

Thank you, wow five years. If your new mill is MT3, mounting MT2 tools should be possible with an MT2-MT3 adapter sleeve. However, unless the adapter and tool accepts a thru drawbar to pull the tool against the adapter into the spindle taper, the tool would eventually come free while side milling.

@@kentvandervelden Thanks for your advise. Didn't know such a MT3-MT2 adapter sleeve existed. I've found online a pm-25mv_manual with exploded view such as your mill. Without the drawbar in it, so I can't consider this adapter unfortunately.

Hi Richard, I wouldn't be able to commit to making one in any reasonable amount of time. In the meantime, have you checked on eBay or considered a long 7/16"-20 bolt? Also, check out this thread (www.hobby-machinist.com/threads/adult-drawbar-for-my-pm25-mv.40056/) My method is pretty wasteful of material to create a wear item. Let me know what you think, if you still want some help, you'll find my email in channel information. Thanks for asking. Probably no one is a fan of the original drawbar.

Wonderful idea! Thank you :)

Thanks Robert, that's good to know.

Not a smart idea to use a 12 point socket on a square bolt. A 12 point socket has a corner angle of 60 degrees instead of 90, causing imperfect contact, and this will eventually start to round off your square.

Orcinus24x5 In theory you are correct. But if you apply a bit of common sense, you are seeing a problem where there is none. It will take many, many years for the head of the drawbar to wear out. Remember we are hobby machining, not running high volume production 16 hours a day, changing the cutter often. There is no need to tighten the drawbar to a breaking point of the wrench either. The square socket is also not a perfect fit due to generous clearance needed to put it on and take it off with ease. After 3 years of using the socket with impact driver all I see is worn black where the socket so imperfectly touches the head, which probably happened at the beginning anyway. BTW, the OEM method is to use flat wrench on the drawbar head. Guess what - the fit is not perfect either, yet it works to a point you don’t come across complaints from hobby machinists about worn drawbar heads. You do see worn drawbar heads abused by too much torque applied with a power drawbar (and with square socket) So calm down, enjoy hobby machining.

+Bud De Hi Bud. That was indeed the original plan and the hex stock fit the socket perfectly. I wanted a ring or washer under the hex (sorry, not sure what to call it) and with the hex stock the maximum diameter would have been the inscribed circle. I also didn't want the interrupted cuts of turning hex stock. Many, for a drawbar, pin a piece of hex stock to a threaded rod, and that would be a much faster and less wasteful approach. Many ways to do the same thing. For what it's worth, in the video, I should have a washer under the drawbar to keep the mating surfaces from wearing. Thanks for the comment. Best wishes, Kent

Send me an email and I'll send you drawings in PDF

sent you my email

Will this drawbar work in the PM30MV? I really like your design

Thanks. The thread is common to R8 but the other dimensions probably need to be increased for the larger mill. Some people use threaded rod and a welded nut, which would be quick and less wasteful than my approach.

Thank you Nico. Maybe someday, but not anytime soon. I had planned to make a power drawbar. My previous Industrial Hobbies mill had an impact wrench based one, but I used endmill holders with the IH mill. With the Tormach TTS I can change tools in a few seconds and feel how secure the drawbar is. I considered a cylinder based system, but have decided against the added complexity. You can see a picture of the air-over-oil power unit that I got for the cylinder at bit.ly/2hEy71E in the power drawbar directory. Maybe a power drawbar seems more critical if having to work around an enclosure? What are your thoughts? Best wishes, Kent

Holy cow, that thing is huge. For TTS (and a mill this size) I believe one needs ~2500-3000 lbs. of tension on the drawbar. A much smaller stacked air cylinder would suffice. Not sure how large of a door your enclosure will have, but elbow room can get tight. Looking forward to more updates on your build!

Nico Seamons Indeed, looks nuts, going to put it on eBay :) I planned for hydraulics to save space on top of the already tight head. Air over oil allowed a smaller cylinder (~1.5") but requires a large power unit for required force. After seeing the Enerpac unit, a friend suggested a electric hydraulic power unit. HossMachine solved the space issue of the air over air units with a pivoting arm that moved the cylinder out further. The space concern is mostly if replacing the motor with an AC motor. I only tax the spindle with a 38mm face mill and when drilling, so I may leave the existing motor. I am replacing the BLDC drive with one with fault and pulse outputs. Are you currently working on a conversion or planning one? I'm currently cleaning up a mess of wiring.

Yep, also currently working on a PM25 conversion. Hoping to get the enclosure done soon. Waiting on a cylinder for a PDB, we will see how that works..

+Nico Seamons Do you have your build online? Sound you are further along than me, but if it would be of any help, this evening, I'll put my rough bill of materials into the same Google drive link.

Thank you Glenn! I have a lot to learn and appreciate your advice. I don't work with steel often but I do enjoy doing so. The feedback provided by the chips is fascinating.

You can use mt2 direct collets. They work just the same, they just have mt2 instead of r8 taper on the outside

Thanks, that's a great suggestion. Fusion360 seems to default to climb milling for all operations that I've tried, unless one explicitly selects "both" or "conventional", and I generally go with the defaults. Do you have rules of thumb you use when selecting between climb and conventional milling? When I make the drawbar wrench, I'm planning to reduce the 3/4" hex down to 17mm to match nuts of the strap down kit. Then I only need one wrench instead of two. I'll follow your advice when re-cutting the hex. Also, in case you are curious, I adjusted the handle of the collet holder, it's held by a couple of set screws. After doing that the collect holder closes completely.

Honestly my PM25 isn't CNC yet (how I stumbled across your videos actually), so I'm not sure about F360 settings for selecting between the two. I just know that when I mill I generally conventional mill all my roughing cuts and do a shallow climb final pass to get a better surface finish. EDIT: I did want to say that doing this mod is an awesome idea though. I hate that little 8mm square on the drawbar. I would make one for myself, but I don't currently have a lathe to cut one on.

turbocharged110 How about using a long 7/16-20 bolt? The following might work. www.fastenal.com/products/details/18898 BTW: I made up a bill of materials for a friend considering a PM25 CNC conversion. Send me your email and I'll send it your way. I plan to make a more in depth write-up, but maybe the BOM will help you.

turbocharged110 In case it's useful, the end mill I was using in the video was one from those standard inexpensive end-mill sets, and they all have sharp edges. I got a couple steel specific endmills from Lakeshore Carbide, with a 20 though radius, I believe, and the new end mills seem to cut much easier than those from the set.

I've never used any from the cheap sets. I generally find NOS endmills on ebay for cheap in odd sizes (5/32", 7/16", etc). I've had good luck so far with Niagara HSS. As far as the BOM goes, I think I know everything I need but wouldn't mind having it just to be sure I'm not forgetting anything. I'll direct message you with my email address.

Thank you, that's a great idea!