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gary wrote:Hi Harry, yes I use the double sided tape quite a bit - it works very well.
Thats good really meaning the high speed cutting doesn't move it out of place , i would said before it would need clamping down for sure but looks like not for that stuff .Harry I was just looking over your pictures again and I noticed it seems you are using "galvanised" all thread.
Yes i am for 2 reasons i wanted Brass but could not afford it and every thing else they sold was bent !!!!!!!!!!!!!!!!!!!!!!!!!!I am not saying it won't work but the galvanised thread offers a great deal more resistance to the nut than does the zinc all-thread. In addition I have found that a lot of the galvanised all-thread has great lumps of "galv" in places which will need to be cleaned off.
I have given it a run its not to bad Gary thats even before even oiling of greasing it seems to work well on both hand turning and connecting my drill...but yes its not the type of thread i wanted .Running a "thread chaser" or die over it may help although that will likely remove quite a bit of the galv and hence may cause the threaded rod to rust.
I hope it works i was going to grease it up for good movement ...one thing to which is a problem you shouldn't really use different metals together as they eat each other away i think its faster than normal rusting.Also it looks as though it is a 5/16 or 3/8 rod.
It fits just right in the bearings Pot luck for me more that choosing right.
I was thinking if i got it to small and fine it might be to slow also looking at sizes other people were using also.Nothing wrong with that but be aware that as a result of that it will have a coarser thread and using a coarser thread will give you less resolution than the finer 1/4" all-thread - 20 tpi that I use.
Perhaps it was a question i should of asked mmmmm i will have another think about this before moving on .
Does steeper motor speed and type and micro stepping in the program for the motors a factor that might make up for it ?
Unfortunately the zinc plated all-thread is only available in Australia in imperial sizes - I personally don't find that a problem - but a younger chap like yourself may object to it.
gary wrote:Yes a microstepping controller may indeed more than make up for it. I shouldn't worry about it too much - just thought I'd let you know just in case.
I am not sure if there is any real difference between a moving bed and a moving gantry - it seems the smaller machines tend to be moving bed and the larger ones moving gantry.
I suppose at the larger size it is better to be moving a router (more or less a fixed mass) than a potentially large item to be milled.
gary wrote:Looking solid Harry, might be an idea to strip that paint off once and for all - you don't want it "gumming" up the works.
gary wrote:Do you have an issue with your drive screw mechanism?
I Know i can do that part but since i have no real plans for this thing making it as i go with parts i have handy and what works and such i have to do that part after i do the Axis movements ,then i can wack those threads in.
I have been thinking about should i rethink the thread size should i try and make it wood free .It's relatively straight forward. The two main issues are the couplers (to connect the drive screw to the stepper), and the anti-backlash nut. The latter we have already discussed, the former I solved by biting the bullet and buying some Lovejoy jaw couplers. You can use rubber tubing to do the coupling but eventually you will want to go to the better type of coupling. If you decide on Lovejoy couplers (or similar) you will almost certainly find you will have to import them from the US- they ARE available in Australia but when I researched them they were about 5-6 times the price of the same item in the US. Alas,, shipping prevents them being very cheap ($10 each in the US) but it's still better than to give money to the robbing bastards here.
Yes Coupling motor to thread has come to mind as well i have looked into it but since i don't have any motors yet apart from what i was thinking of using at the start its a problem that will have to wait till i know what i am doing here .
I was looking at making them my self again cost cutting ,i have seen the tube of rubber or plastic tubing used i think i can make some thing better but if ebay sales are kind to me i will look into those nice couplings.
Yes we do get ripped off here whats for sale over seas ,thats a nice thing about ebay for us .
But anycase i will look into them if i can .Do NOT be tempted to buy those couplings from Jaycar - they are way overpriced and not suitable for this application.
Oh i didn't know they sold any ! my hope was work it out old trial and error make and see.
NOTE! It is essential that the coupling prevents any significant sideways (lateral) forces from reaching the stepper otherwise the steppers will not last long. All of the lateral force should be absorbed by the bearings either end of the drive screw - ideally these would be thrust bearings but skate bearings seem to do well and are very cheap and readily obtainable.
harry dalek wrote:I was thinking more of this idea when i started.
http://www.youtube.com/watch?v=i0sTrSkoDs0
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