We are sourcing common inexpensive acme, so only 1 start. I am surprised we found any affordable acme, at all.

 

Just wondering...

Whats got you guys wanting to change over to Acme?

Eric

 

Guys, Thanks for the feedback and compliments, I was so excited by this low cost mod that I wanted to get it done as fast as possible, yet have high performance results. I also wanted to do the mod in a way that could be done on a totally stock PhlatPrinter. I think this may be one of the best mods as far as bang for buck!

 

For less than $25 and with the stock steppers you can almost double your cutting speed in Y and greatly improve Z. This means it takes way less time to finish cutting a sheet of foam. Also this mod can be done on a totally stock PhlatPrinter.

 

Yep!, the hose clamps that came with my PhlatPrinter kit are more than long enough to go around the expanded hose and 3/8-12 acme rod.

 

3/8-12 Double-Start is effectively 6 TPI. That would be a radical change from the 28TPI all-thread, and I doubt the stock steppers would have any chance of driving them, as a 6 TPI drive would need a lot of torque.

 

Dorsal,
This is why I am confused as to why everyone is jumping to this.

Eric

 

I agree with that statement about the use of all thread vs acme for the most part, though I have seen all thread drive many objects.

I thought Pennys were used for making change and purchasing (something really cheap) but they are now used for linear bearings on the phlatprinter, go figure.

Eric

 

The post I made above was related to a Double-Start 3/8-12 (also known as Fast-Travel or Multiple Start threads). The nut will travel twice as far with each turn as a Single-Start 3/8-12 thread. A Single-Start 3/8-12 thread will travel 1 inch in 12 turns, a Double-Start thread will travel 2 inches in 12 turns.
I am using Single-Start 3/8-12 Acme shafts, with the Standard Stepper Motors, and currently running about 40 ipm. I was running at 60 ipm, but my SmoothStepper board (which allows me to control my PP from my laptop) is very sensitive to radio-frequency noise generated by the garage-door opener and garage freezer, so I slowed it down until I get a grounded metal control-board enclosure installed. I'll probably push it back to 60 after that.
I'm sorry I didn't explain that better the first time.

 

blindflight,

Appreciate the code. I didn't want to submit my email address for their special offers, so I probably wouldn't have gotten it, otherwise. Enco seems to be actively trying to attract the little guy. btw I wanted to get me some of the metal acme nuts, since I neglected to buy some the first time. If you buy up to 3, shipping is also free. Mine are on the way.

-Kwok

 

Dorsal, just a thought, but I bet most of the electrical noise (EMI/RFI) you are getting is through the power line. That's unless you are really close to the garage door opener or freezer, like within two feet or less. The grounded metal enclosure should help some also though, maybe both together would be the best.
I have always liked Tripp-Lite surge suppressors, here are a few cheaper ones with decent EMI/RFI filters

Up to 20- 40 dB EMI / RFI filtering.
HT706TV http://www.tripplite.com/EN/products/model.cfm?txtSeriesID=73&EID=14382&txtModelID=2811
HTSWIVEL6 http://www.tripplite.com/EN/products/model.cfm?txtSeriesID=73&EID=14382&txtModelID=3618
40-80 dB EMI / RFI filtering.
These ones are cool because the plug right into a normal double gang wall outlet.
ISOBLOK2-0 http://www.tripplite.com/EN/products/model.cfm?txtSeriesID=74&EID=345&txtModelID=3974
ULTRABLOK http://www.tripplite.com/EN/products/model.cfm?txtSeriesID=74&EID=345&txtModelID=3980

 

I made a new tap, because my old one didn't have enough chip clearance and I had to keep backing it out. New one cuts alot better. It has less taper at the tip and the slot curves down almost to the tip center, otherwise it just goes away when you taper the tip.


Attached files

 

Here is a video of me braking in a HDPE nut with a drill. Making the tap is an art form. You can make little adjustments to make the resulting nut tight or loose. If it's really tight, then you need to adjust the tap. If it's alittle tight, then you can try running the tap through again from the other side. Once it's about right, then you can do this brake in with the drill, to loosen it up the rest of the way.

http://video.google.com/videoplay?docid ... 9467&hl=en

-Kwok

 

rjarois,
Thanks. It wouldn't have been possible, without info I picked up here. Hope this helps someone else. Starting the tap (and cutting) is really easy. Not much force at all. Cuts easily until it starts to jam, but that really has more to do with a good tap design. My 1st tap, I have to back out all the way twice and clean off the tap. It's only 1/2" think, so I can get away with a poor tap. But my 2nd can actually go through in on shot, but I am still careful. Also, if you make the tap too perfect , you can actually get a nut that is too tight. Probably, the draw back of making a tap from the same rod. That happen with my new tap. I got rid of all burs and sharp edge that weren't completely necessary. Wow, the nut threads look nice, but way too tight. Finally, I had to hit everything lightly again with the dremel to get some burrs back. This loosen it up and everything was fine.

-Kwok

 

Might be because the guy was using the low density PE, instead of high (LDPE vs HDPE). I was originally going to use a plastic cutting board, I bought from the grocery store. But I was warned not to:
viewtopic.php?f=12&t=141&start=25#p1685
If you follow along, I figure out an easy density/buoyancy test to figure out what type it was and another easy test to measure it's exact density. I ended up, buying some of the good stuff, online @ usplastic.

-Kwok

 

Kwok, how did you do the tap? How did you make the flutes? I tried to do it and it doesn't work out for me. I made one attempt and when I had it loose like you have it in the video, there is so much play I can rock the allthread in the nut back and forth. It was tight in the beginning with no play, but when I used the drill to loosen it there was lots of play. I don't know if there will be backlash, but I would be surprised if there is none. I don't use an acme thread, I use an 1/2" allthread but it should make no difference, I think.

Yoram

 

Yoram,

I just used an 4" angle grinder to do the flutes. This one actually: http://www.harborfreight.com/cpi/ctaf/d ... mber=91222

My 1st 4 nuts were rejects, so it might take some practice. Are you removing burrs and doing a good finish grind (I used the dremel) on the tap. What materials are you using for the nuts? Are you sure it's HDPE and not low density? Also, from my experience, loosening is just a fine tuning finish procedure. In other words, the nut should be pretty close already with just the tap. It took me a while to figure this out. I was expecting, it to correct nuts that were too tight to begin with. What I had to do was run it through the tap again or even sharpen up the tap cutting edges to remove more material.

I've never done it with alltread. You need to use your best judgement. If they are ok before, then can they be use without loosening. Allthread normally have a very bad surface finish. Did you see where someone posted about polishing allthread? Even perfect Allthread will have alot more friction, by design. And I would think a perfect fit is not what you want. Remember, the reviews from dbtoutfit's ZBN, that they had play in the radial direction and none in the direction of motion. My guess, is he probably had a special custom shaped tap made. So it very well may make a difference, that you are using allthread.

You say, you can rock the alltread back and forth. Do you have any play back an forth? Just as long as there is no play in the direction of travel, it shouldn't matter if it rocks. I can confirm that it's not like that with acme thread. It's pretty solid in any direction.

-Kwok

 

Kwok, I have a Harbor-freight grinder too, the cheaper one.

I tried to cut the flute with the rotozip but that was not a good idea. I'll try it with the grider and a cutting blade. You used a cutting blade, right?

The play that I have talked about is not in the movement direction. I don't know yet if there is play in the movement direction. That's what I worry about.

I had posted two or three days ago about the material that I have. I had put some in the lathe and it CHIPPED not melted. Justs like Eric (I think it was him) said it should do if it HDPE. It machined just like aluminum, only nicer. The finished surface was like a mirror and hard like a rock.

I remember someone posting about polishing the allthread. I'll do a search and see what I can and should do.

Yoram