what to do with a free scrap dumpster find ?

Boston gear has a PFD on their web sit at the end of the PDF they have a lot of technical information on gears that's handy. most likely it would be to large to post here so look them up if you have a need for information on gears.

the amount of backlash is based on the diametral pitch of the ratio change gear(spur gear) the larger of the two. the pinion refers to the smaller gear. the diametral pitch is the number of teeth around the circumference per inch of circumference in my case the D.P. is 16 so that puts me in the .003 range of backlash. i thought it was far worse than this because i confused the pitch diameter and the diametral pitch at first. gears are a specialty section of machining and i have never got into this section. but here is a screen grab of some basic guided lines on backlash and center distance placings and how slight changes to the center distance of shafts can play into the backlash.

 

after looking some more the gear set up is what i will probably end up sticking too. you can take the backlash out with springs but this is more of a light duty solution and you can do it buy using two gears one on a hub staked to the shaft and a second that spins on the hub and then set with locking screws. the second option is kinda like a double nut on a lead screw loaded in opposing directions. this is something that would need adjusted over time but a more robust drive i think.

a 14.5 degree pressure angle is what was on the machine to begin with and this would be better suited over a 20 degree pressure angle since the 14.5 degree angle runs smoother than a 20 degree and can run faster. just something that pertains to my situation.

down side is i found gear stock so i could custom make what i need but i only found 2 places that sell it an the one place is way to expensive and the other place only offers sock with a 20 degree pressure angle. so this is still up in the air.

  this was the only thing i could find on speed limitations for these spur gears. so based on this i can get about 4,500 RPM on the smaller gear and keep it within the limits. but running that fast i think i will have to keep these gears in an oil bath if they are to last any length of time. i can't get away from this being costly. i think my starting point will be switching to a 2:1 ratio to drive the ball screw since i can run that ratio and not have to change anything as far as center line spacing of the shafts. at that ratio. the ball screw rotation will be in a range of speed that i can put an oil seal on the shaft and make some kind of housing for the gears and still have a decent rapid rate on the heavy lifting axis. the extra torque on a reduction with help keep things moving and the ratio will produce rapids more in tune with what i would like to see. a gear drive is noisy so this will help keep noise down as an added plus as well.

the cheapest solution i can find is just to buy a second gear and modify the two larger gears to create an anti backlash gear. so 3 gears will rum me $110 plus oil seals and material for the housing so not very cheap to drive a screw but options are limited and i think this is my best option.

i would think a lot of the information on the gears here would carry over and apply to rack drives so this might help others.

had i little bit of time to start the motor mount parts of this build. i have some screw jacks that will attach and act as the belt tension to slide the motor mounting plate on the stand offs. the motor mounting plate just has some slots and a 1/2 13 bolt on both side to lock it in place. the screw jacks are just to lift the motor mount since it has some weight to it to make belt adjust easy.

i also have some new gears to drive the ball screw. i switched to a 2:1 ratio the original set up was 4:1 but that's pretty slow with a 5mm ball screw. i found a drive sizing program from ABB just to get some basic info and it looks like it should work fine. i also picked up some oil seals incase i can fit the gears in a case but space is limited so i have them if i need them. i also picked up a din rail power supply just for the cooling fans not sure if that was the best solution but it was easy enough.

the larger gear will attach to the the ball screw. rather than a key i will just roll pin it to the shaft and use the nut for the ball screw to to lock it down. the set of gears on the left are original and the ones on the right are what i will switch too. simple but should work just as well as being keyed. i have an extra large gear in case i need to do something about backlash as well but will probably see exactly what is going on before i commit to something more complicated.

     

i started to work on the lead screw for the head and was thinking backlash might be an issue with the gears that drive it, but i don't think it will be an issue after all, since the gear only has a typical .003 of backlash with standard centerline spacing i think it can be adjusted to as close as you can get before things bind. the pinion gear is fixed to the head but the ball screw and gear attached can float in any direction. the holes that mount the ball nut and bearing block at the end have some clearance in them so you can actually adjust the shaft to the fixed pinion gear by about .01 in what ever direction you need to go.

i may have been over thinking this

had more time than usual to work on this but it was not by choice. i have a love hate relationship with my truck. i love it because it's paid for but i hate it when it comes time to get it inspected for the year to keep it road legal. so in between waiting for prats to come so i could work on that i was working on this project since i was trapped at home

needed to have a place to attach probably 60lbs of motor and upgrades too and drive it all up and down. i need to open the back side of the cast iron block the houses the bearing for the shaft so i can get to the nut better and probably slot the cast iron so i can get to the set screw on the nut as well. i still have a bunch of little stuff to sort out but i'm getting close to getting thing attached and back on the machine at least.