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Tool Post Grinder -Making a new one...
- Thread starter Ray C
- Start date
- Joined
- Nov 16, 2012
- Messages
- 5,596
Well, it seems to be working... -but not without a lot of chasing around. None of the motors my friend had were suitable. After making shaft adapters and trying two of them, I bit the bullet and bought a large general-purpose 2 Pole (3600 RPM) 120/240 motor. Since the 1/2, 1 and 1.5 HP units all weight about 18 lbs, what the heck, I bought the 1.5 HP unit because it was only 39 bucks more. It was on sale at Harbor Freight and it runs surprisingly smooth and quiet. It's a larger form factor than I wanted but the TPG does not get used all that often and, I might find other purposes for it later.
I had two wheels; a 4" 80 grit which I didn't have good luck with and a 5", 60 grit which did a nice job. I just ran a quick test piece which was the left-over hardened shaft from earlier in the project. I put a nice carbide cut on it, switched over to the TPG and gave it a shot. It works quite well. I followed-up with a buff and you can judge for yourself...
Pretty obvious... the motor is temporarily mounted because I just wanted a test run. Overall, it runs very quite and you can hear the air coming off the wheel. I still didn't receive one of the oil seals so, I make a temporary rubber gasket. Surprisingly, it's not leaking. I let it run for 30 minutes and the TPG housing just barely felt warm -maybe 10-15 degrees warmer than the lathe bed.
The picture right now shows a 1:1 sheave setup because the buffing wheel is only rated for 3600 RPM. If I stick with this motor, I'll need to make a sliding motor bracket to accommodate different diameter sheaves.
And here's piece after a 1 pass buff. It's pretty smooth. Now for the bad news... I was going to change back to the 5" #80 and in my frantic hurry to do so, I dropped it and chipped the edge -so it's in the garbage can where it belongs. Oh well, I guess it was time to get another one anyhow.
Over the next couple days, I'll put a few finishing touches on it -and hopefully the grease seal will arrive so we can do the final assembly with the permatex gasket stuff between the body segments. Right now, I just made gaskets out of thin paper -and oddly enough, it's not leaking... -Go figure.
I'll check back in a couple days on this project when the oil seal arrives. In the mean time, I'll install an oil drain plug and pretty-up the base a little.
Ray
I had two wheels; a 4" 80 grit which I didn't have good luck with and a 5", 60 grit which did a nice job. I just ran a quick test piece which was the left-over hardened shaft from earlier in the project. I put a nice carbide cut on it, switched over to the TPG and gave it a shot. It works quite well. I followed-up with a buff and you can judge for yourself...
Pretty obvious... the motor is temporarily mounted because I just wanted a test run. Overall, it runs very quite and you can hear the air coming off the wheel. I still didn't receive one of the oil seals so, I make a temporary rubber gasket. Surprisingly, it's not leaking. I let it run for 30 minutes and the TPG housing just barely felt warm -maybe 10-15 degrees warmer than the lathe bed.
The picture right now shows a 1:1 sheave setup because the buffing wheel is only rated for 3600 RPM. If I stick with this motor, I'll need to make a sliding motor bracket to accommodate different diameter sheaves.
And here's piece after a 1 pass buff. It's pretty smooth. Now for the bad news... I was going to change back to the 5" #80 and in my frantic hurry to do so, I dropped it and chipped the edge -so it's in the garbage can where it belongs. Oh well, I guess it was time to get another one anyhow.
Over the next couple days, I'll put a few finishing touches on it -and hopefully the grease seal will arrive so we can do the final assembly with the permatex gasket stuff between the body segments. Right now, I just made gaskets out of thin paper -and oddly enough, it's not leaking... -Go figure.
I'll check back in a couple days on this project when the oil seal arrives. In the mean time, I'll install an oil drain plug and pretty-up the base a little.
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
Thanks...
I hemmed and hawed about the motor.... Size wise, it doesn't look very appealing but, the motor weighs 19lbs which is as much as some of the treadmill and other DC motors I looked up. There are no clearance problems or that would have shot it in the foot right away. Anyhow, I weighed the whole setup and it's 33lbs which is about the same as a 1/2 HP Dumore TPG. If I find a better motor, that will be great. This one here will always find a purpose somewhere else if I find a better one.
Ray
I hemmed and hawed about the motor.... Size wise, it doesn't look very appealing but, the motor weighs 19lbs which is as much as some of the treadmill and other DC motors I looked up. There are no clearance problems or that would have shot it in the foot right away. Anyhow, I weighed the whole setup and it's 33lbs which is about the same as a 1/2 HP Dumore TPG. If I find a better motor, that will be great. This one here will always find a purpose somewhere else if I find a better one.
Ray
- Joined
- Jun 17, 2012
- Messages
- 2,220
Looks good Ray! As Tim the Toolman Taylor would say...it needs "more power".:thumbsup: I have the 1 hp , 1725 rpm version of that motor running my southbend 9" lathe and it doesn't even groan a little bit. 
) I just may have to build me one of these Ray. I've been looking around for a used Dumore TPG and the beat up ones are going for $500 or better. I got 2 motors sitting on the shelf over here. A 1/4hp 1725 rpm and a 1/3hp 1725 motor just waiting to be put to good use. Getting the right bearings at the right price is gonna be the challenge.
Marcel
) I just may have to build me one of these Ray. I've been looking around for a used Dumore TPG and the beat up ones are going for $500 or better. I got 2 motors sitting on the shelf over here. A 1/4hp 1725 rpm and a 1/3hp 1725 motor just waiting to be put to good use. Getting the right bearings at the right price is gonna be the challenge.Marcel
Last edited:
- Joined
- Nov 16, 2012
- Messages
- 5,596
The 1/3 HP would be desirable. The taper bearing has a lot of force on it; as such, the shaft can be spun with your fingertips but, it's not freewheeling. Also, the oil seal is a very tight fit. Finally, with it filled 1/2 way, even with light oil, the motor will constantly be pushing against the viscosity of the oil. -Moral of the story, 1/3 or 1/2 HP is the way to go.
You're right about the Dumore units... $money$... Ones in good shape are going near a grand. I've got about 100 bucks invested in this. 10 for oil seals, 20 for the two rear bearings, 10 for the wave washers 10 for the thrust washer -and I think 25 for the front bearing (lucky eBay win) -and another 20-25 in miscellaneous stuff like permatex, threaded rod and a handful of nuts & bolts. All the metal was shop-drops. -Of course, the motor was 139 on sale so, I guess this thing really cost 239. No doubt, I'll use the motor for other things here & there...
I've always wanted to pull a Dumore apart just to see what magic they have inside... Anyhow, I designed this thing with simplicity in mind and it was on the drawing board about 2 or 3 times before settling on this. I came up with other designs but this one takes into account expansion of the shaft as it warms up. The amount of space for the wave washer is critical. Too much and the shaft will wobble... too little and it will seize the bearings when it expands to size -and yes, I actually calculated the amounts of expansion for 1045 steel. All those cavity depths were important within a thou.
If I had to build another one, I'd only change one simple thing... Only use three holes/bolts instead of the five. I thought about making the body a smaller diameter by threading the body sections (male and female) and screwing them together instead of using draw bolts. -Too much work and didn't feel like messing with it -although it would have been cool to do it that way and I could have had further optimization of the side brackets that hold it to the base. ... In a nutshell, I didn't want to do all that stuff not knowing if it was going to work or not.
I'm actually impressed with the HF motor. No doubt, I'll get a double pole switch and wire it for 240. It's 120 now.
Ray
You're right about the Dumore units... $money$... Ones in good shape are going near a grand. I've got about 100 bucks invested in this. 10 for oil seals, 20 for the two rear bearings, 10 for the wave washers 10 for the thrust washer -and I think 25 for the front bearing (lucky eBay win) -and another 20-25 in miscellaneous stuff like permatex, threaded rod and a handful of nuts & bolts. All the metal was shop-drops. -Of course, the motor was 139 on sale so, I guess this thing really cost 239. No doubt, I'll use the motor for other things here & there...
I've always wanted to pull a Dumore apart just to see what magic they have inside... Anyhow, I designed this thing with simplicity in mind and it was on the drawing board about 2 or 3 times before settling on this. I came up with other designs but this one takes into account expansion of the shaft as it warms up. The amount of space for the wave washer is critical. Too much and the shaft will wobble... too little and it will seize the bearings when it expands to size -and yes, I actually calculated the amounts of expansion for 1045 steel. All those cavity depths were important within a thou.
If I had to build another one, I'd only change one simple thing... Only use three holes/bolts instead of the five. I thought about making the body a smaller diameter by threading the body sections (male and female) and screwing them together instead of using draw bolts. -Too much work and didn't feel like messing with it -although it would have been cool to do it that way and I could have had further optimization of the side brackets that hold it to the base. ... In a nutshell, I didn't want to do all that stuff not knowing if it was going to work or not.
I'm actually impressed with the HF motor. No doubt, I'll get a double pole switch and wire it for 240. It's 120 now.
Ray
Looks good Ray! As Tim the Toolman Taylor would say...it needs "more power".:thumbsup: I have the 1 hp , 1725 rpm version of that motor running my southbend 9" lathe and it doesn't even groan a little bit.
Marcel
- Joined
- Nov 16, 2012
- Messages
- 5,596
Had a little time to play with this again today after I chased around to find a 5" wheel. Here's piece freshly ground. I took two passes; the first was about 1/4 thou and the last... I barely blew on the dial from the previous pass.
The results are good. This piece was just ground and not polished. The iPhone camera doesn't do it justice. When I look at it closely, it's so polished that my eyes can't focus on it
-Still waiting for the oil seal... I want to hurry-up and put this project behind me.
Ray
The results are good. This piece was just ground and not polished. The iPhone camera doesn't do it justice. When I look at it closely, it's so polished that my eyes can't focus on it
-Still waiting for the oil seal... I want to hurry-up and put this project behind me.
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
Careful now... you might accidentally do a Vulcan mind meld and you'll find yourself howling at the moon and staying up all night trying to figure out how to remove 0.0001" of metal off a round shaft.
Feed... Slow! The lathe was running at/around 300 RPM and the feed was set at the lowest speed which I think is 0.0015 IPR. That ground section is about 3" long. I didn't time it but, would guess it took 6-7 minutes to go the 3 inches.
The wheel is a 60 grit, 5" diameter AO only rated for (and run at) 3700 RPM. I'd like to get a finer wheel just to see how that looks and I plan to get 6000+ rated wheels and run at/around 5000 to 5500 RPM.
Ray
Feed... Slow! The lathe was running at/around 300 RPM and the feed was set at the lowest speed which I think is 0.0015 IPR. That ground section is about 3" long. I didn't time it but, would guess it took 6-7 minutes to go the 3 inches.
The wheel is a 60 grit, 5" diameter AO only rated for (and run at) 3700 RPM. I'd like to get a finer wheel just to see how that looks and I plan to get 6000+ rated wheels and run at/around 5000 to 5500 RPM.
Ray
Wow nice! What grit wheel are you using? What rate of feed on the long feed? Picking your brain to stash in mine!