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[4]

Tool post grinder Build

January Project of the Month [3]
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GoceKU

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#1
I've been needing an tool post grinder almost as long i've had the lathe and after not be able to found one to buy i've resulted to building one. The plan is to build one that i can mount in my tool holder and can adjust stone stick out as an tool cutter, this will allow me to do inside grinding and outside grinding with minimal stick out. For the motor i've chosen this old pressure washer motor to use, but the shaft is way to short to mount a pulley, so i've disassembled it and started with extending the shaft, i've done this process couple of times before and wanted to share how i'm doing it, in my next post.
 

GoceKU

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#2
This is the motor i'm planning to use in this build because is compact and powerful, is rated at 2Kw (2,72Hp) around 3000rpm. The first thing to sort out is the short output shaft, so i've take it apart and and found that i'll need to buy an sealed bearing and the insides look good no corrosion and the copper looks clean, then i chuck up an 18mm piece of C45 and turn down one end to 6mm and made a taper for the weld then i traded it for M6. The rotor has M6 threads so only thing i did is to chamfer the edges on my bench grinder then i faced the shaft i made earlier tight, to hold straight when welding, than i wrapped the rotor in a piece of leather to protect it and welded the shaft.
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GoceKU

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#3
This process is not finish, now i need to chuck the rotor in the lathe and cut it to run straight, i make my extension shafts 2-4 mm bigger then what i need to have enough material to cut them straight, this one had moved a lot, i wrapped the rotor in some thick duct tape i chuck it pu in the lathe and indicated it from the seal journal, drilled and supported the other end with and live center, and began taking cuts but i was in a hurry and tried to take too much at once and the the rotor move on me, so i stopped and will continue letter when i have more time.
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kvt

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#4
why not use brass shim or something like that where you can grip it better. The tape will always give a bit, and also is not as consistent thus can be off center Just a thought. Looking nice.
 

GoceKU

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#5
I usually use copper shim but could not find any so i used first thing that came to hand, ( duct tape).
 

Bob Korves

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#6
Did you use high precision duct tape? ;)
 

GoceKU

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#8
Today i continued working on this shaft, yet again i've changed the tool i'm using and took my time making small cuts and got it finish to size, the bearing jarnal is 17 mm and made the shaft extension 16mm so i can use oem belt pulley, i left the length longer than i need, i'll shorten it later when i figure out my drive pulley.
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tertiaryjim

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#9
Looking good!
I've used the same method on a 3600 rpm fan shaft but TIG welded.
It ran in a corrosive enviroment and lasted over a year till the fan lost balance weights.
It then shook itself pretty hard. Had to do a static balance, new bearings n seals, and it was running again.
Had been greatly concerned that such a long shaft added on would be a problem.
 

GoceKU

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#10
I'm not still done with modifying the motor but i wanted to start on the spindle and its housing, i plan to use 25x25 mm square solid piece of 4140 which seems to be the sweet spot for my tool holders, but i don't own an 4 jaw chuck so i made this sleeve, started with solid 45mm 1045 steel, drill and bore the inside to the outside diameter of the square stock, then i cut slot using an angle grinder and test fit it in the chuck, unfortunately that was all the time i had for tonight.
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GoceKU

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#11
Over the work week days i hardly have any minute to spare but managed to do little 'turning' i did faced off both ends and radius on them, it seems to be turning on center, but i'll need to take it easy when drilling because it's only holded in couple of small points and could easily move and slip.
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GoceKU

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#12
Today i had some time off my job so i continued to work on this project, first centre drilled both sides, then i drilled one end with 19mm drill which is the exact size i need for the bearings i've selected, wich you can see, i've also bought oil seals to match the bearing size, but the drill made the hole oversize, so i had to cut it off and start over, so i drill it one size smaller and used an boring bar to bring it to the 19mm i needed, then i drill the the rest of the way with an 15 mm drill, but my drill could reach only half way, for the other side i started by drilling the thru hole, had to run the drill all the way to reach, then i drill and bore it to 19mm, in the last picture you can see how this price will be held in my tool post, i'm considering should i mount the motor at 90 degrees or at 45 degrees from it.
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Silverbullet

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#13
I like what I see , waiting for more .I too would like one and the prices floor me , even junk goes high burnt out motors with them. I have a air die grinder which I've done some grinding with it mounted in the tool post. But a real grinder at times would be so much better.
 

GoceKU

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#14
Today i continued with working on the spindle shaft, i needed an 12,7mm shaft as the bearings i've chosen are not metric i had to start with an 14mm piece of 4140 and turn it down to an length of 310mm, had to move the tailstock around to remove the taper, after i got it close i use sandpaper to remove the last little bit, then i turn down the end to 10mm and threaded it with M10, more to come.
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GoceKU

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#15
It was late last night and i was tired when i wrote my post and forgot to mention couple of thing, i had to spin the shaft at 1600 rpm fastest i've run my lathe on purpose, i had lot of deflaction and chater even at 1280 rpm so i went to 1600 rpm which speed things up constable.
 

GoceKU

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#16
I've been really busy with my day job but this weekend i did some work, big part of this build is the belt drive, after looking around i found this aluminium casting, it use to be an air valve, but the end wall was too thin to be fixed to an shaft so i asked a friend to lay down couple of beads, he added about 10mm material, i machined the flats for the belt and found that i'm missing some more material, so i'll take it back again to my friend to add more material by tig welding.
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GoceKU

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#17
Today after work i stopped by a friend's place, he is a pro welder he lay down couple of beads on this casting, this only took couple of minutes so i had some time to do some more turning on the lathe, i turn down the welds and drill the center hole, the plan is to assemble the motor and mark the position for the belt pulley, then drill and tap for couple of set screws, then disassemble the motor and finish turning the pulley on the rotor
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, today i also chuck up the front cover for the motor, and turn it flat.
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GoceKU

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#18
Today i continued working on this project, i started with an 140mm square stock, face it off and chamfer the edges, then drill half the way with 15mm drill, then i did the same on the other side but drill it with 8,5mm drill and tap M10 threads, then i took it to the big garage and spend some time jigging it and welding it, more to come.
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GoceKU

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#19
I had some time in between machining couple of things so i decided to drill and thread three hardened steel set screws, this should be sufficient to transmit all the power, they are also deep enough so i can cut multi row belt grooves, more to come.
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