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New to me Hartford Mill
- Thread starter Susquatch
- Start date
I see! This is very good news to me. I like that.
I'll have to see if I can find the mod you refer to.
The motor for my Hartford arrived today. Very nice. Same colour as the mill - well close enough anyway. A fair bit taller and skinnier than the old motor. Also has a top spindle under a removable cover that I assume could be used for position or speed feedback to the VFD. The data label says it can be run from 0 all the way to 3600 rpm. Who needs to change belts with that range!
I opened the wiring box. It has 11 wires that all appear to be identical with no labels....... Oh oh.
There is also a horizontal
mounting bracket welded to it. It looks funny given that it will be face mounted. Maybe I can find something to put on it like a switch or breaker box or something like that so it fits in. Perhaps even the VFD if I end up adding an external potentiometer and an external start stop.
I also ordered a few parts and a top end rebuild kit from H&W yesterday morning. Already at customs tonight.
Lastly, last night I finished laying out and marking up that 1/2" plate to make the motor adapter plate with. I also drilled the micky mouse ears (as @Dabbler calls them) just because I could and because... Well, because why not! I'll be rough cutting the adapter with my torch outside tomorrow if we don't get too much rain, then cleaning it up with a grinder, and then figuring out how to mount it in my lathe to cut the motor relief. Too bad Mickey's ears are bigger than my face plate.
Lots of fun!
I opened the wiring box. It has 11 wires that all appear to be identical with no labels....... Oh oh.
There is also a horizontal
mounting bracket welded to it. It looks funny given that it will be face mounted. Maybe I can find something to put on it like a switch or breaker box or something like that so it fits in. Perhaps even the VFD if I end up adding an external potentiometer and an external start stop.
I also ordered a few parts and a top end rebuild kit from H&W yesterday morning. Already at customs tonight.
Lastly, last night I finished laying out and marking up that 1/2" plate to make the motor adapter plate with. I also drilled the micky mouse ears (as @Dabbler calls them) just because I could and because... Well, because why not! I'll be rough cutting the adapter with my torch outside tomorrow if we don't get too much rain, then cleaning it up with a grinder, and then figuring out how to mount it in my lathe to cut the motor relief. Too bad Mickey's ears are bigger than my face plate.
Lots of fun!
Got most of the head apart.
Looks like mine is greased too so grease it will be. There is no way that I can see to get oil in there.
One of the screws holding the belt retainer ring broke on removal. I noticed screw driver marks on the ring under it that tell me someone has already been working on it and failed. I'll have to extract the screw stub and see if I can find a replacement.
Turns out, the back gear bearings are not actually shot. All that movement was because ALL of the bull gear cover screws were VERY loose. All were sticking up a 16th or so and could be removed by hand. Thus all the movement was actually cover movement! Not bearing play. The bearing itself looks and feels good and so does the bearing fit in the cover. It was easy to knock out but was tight enough not to spin.
Once I get it cleaned up, I'll have to see if the screw holes in the cover are oblique or worn. If so, looks like tapping for bigger screws will be in order, or maybe short bushings.
Wife wants me to cut grass before it rains so no adapter torching today......
Hit a small snag today.
The pin for the bull gear shift fork would not push out the backside as per the repair books and the H&W videos. I whacked it with a small sledge lightly at first and then about as hard as I dared without cracking the housing. Hard enough at the end to fatten the pin a bit. I'm gunna try making a bracket to help press it out from the backside instead.
Any better ideas to get that little bugger out?
Also, I discovered that all the roll pins were deformed (undersized) and the alignment pin holes were worn on the bull gear cover.That's prolly from wiggling around with loose screws. I'll prolly install a few more alignment pins, and enlarge those ones. Maybe make them all 1/4". The originals measure 195/197 so they were prolly 2 tenths originally.
The pin for the bull gear shift fork would not push out the backside as per the repair books and the H&W videos. I whacked it with a small sledge lightly at first and then about as hard as I dared without cracking the housing. Hard enough at the end to fatten the pin a bit. I'm gunna try making a bracket to help press it out from the backside instead.
Any better ideas to get that little bugger out?
Also, I discovered that all the roll pins were deformed (undersized) and the alignment pin holes were worn on the bull gear cover.That's prolly from wiggling around with loose screws. I'll prolly install a few more alignment pins, and enlarge those ones. Maybe make them all 1/4". The originals measure 195/197 so they were prolly 2 tenths originally.
Well, I plowed ahead and used a big C-Clamp some old 3/4 plate, some giant washers, and a custom pin to push it out. I thought it came out rather easy until I noticed I had just bent the handle on the C-Clamp like a big clock spring. No go on the pin. So I put a few more bends on the handle and then whacked the backside of the clamp where the pin was. IT MOVED! What a great feeling a tiny 32nd of an inch can provide! I tightened the clamp a wee bit more and then whacked it again. Before you know it, the pin was out!
Yup, there is a 3/16th shoulder in there. That pin was never pushing through without breaking the housing. Should I drill it out or leave it the way it is?
Got the forks and gear out with another makeshift puller.
The stud came out with yet another home made puller. Unfortunately, the bearing didn't come with it.
Right about now I'm feeling a little bit like Custom Pullers RI.....
Next up is that pesky bearing..... I hope the grease trick works! Otherwise it's another fancy puller on the to do list.
Tomorrow is another day.
Yup, there is a 3/16th shoulder in there. That pin was never pushing through without breaking the housing. Should I drill it out or leave it the way it is?
Got the forks and gear out with another makeshift puller.
The stud came out with yet another home made puller. Unfortunately, the bearing didn't come with it.
Right about now I'm feeling a little bit like Custom Pullers RI.....
Next up is that pesky bearing..... I hope the grease trick works! Otherwise it's another fancy puller on the to do list.
Tomorrow is another day.
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As members may know, the bearing is out. See @architect 's Bridgeport Project. I ended up making a custom collet.
So, another question for you guys. I'm virtually certain that those bearings got wrecked by improperly tightening the bull gear cover. The screws came loose and the cover wore against the alignment pins. I don't think I can simply reassemble it and have it last. So I'm thinking about assembling the cover plate with some oversized pins where the old ones were and then adding a few more pins by just drilling through the cover into the head and then tapping a pin into the hole. Four more pins is a bit of over-kill but should provide the needed integrity.
What do you guys think?
So, another question for you guys. I'm virtually certain that those bearings got wrecked by improperly tightening the bull gear cover. The screws came loose and the cover wore against the alignment pins. I don't think I can simply reassemble it and have it last. So I'm thinking about assembling the cover plate with some oversized pins where the old ones were and then adding a few more pins by just drilling through the cover into the head and then tapping a pin into the hole. Four more pins is a bit of over-kill but should provide the needed integrity.
What do you guys think?
I'll make it so!
I think yours is beautiful.
As time passes, I'm leaning more and more toward keeping the Hartford. The bed and screws are in much better shape than the Bridgeport and with the new 1000:1 Motor and VFD, it is practically a variable speed. With the top half off, I can now tell that the spindle is probably in perfect condition.
It will probably also be easier to sell the Bridgeport and now that it runs, perhaps even at a healthy profit.
I'll probably make a decision as soon as I get it running which is only waiting on bearings and a new back gear pulley and belt.
I decided to see what it takes to marry the motor shaft and pulley today. Ughhhhh......
The motor has a 3/16 Keyway in it, and the pulley has a 7mm Keyway. Here we go again........ Prolly going to have to make my own because I can't seem to find that anywhere.
Does anyone know what the proper height dimensions of a 3/16-7mm stepped key should be?
The motor has a 3/16 Keyway in it, and the pulley has a 7mm Keyway. Here we go again........ Prolly going to have to make my own because I can't seem to find that anywhere.
Does anyone know what the proper height dimensions of a 3/16-7mm stepped key should be?
The limiting factor is the 7mm portion of the stepped key. It has to be low enough so as not to interfere with the 3/16” keyway. I would start with the 7mm key. Get it to fit nicely into the pulley (close sliding fit). Now you can see how high it can be maximum (both the 7mm portion and the key as a whole). Grab the 7mm portion in the milling vise and machine equal steps per side (like making a T-nut). Sneak up on your dimensions and you should be good to go. You can easily remove the key from the vise for trial fitting. I would make the 3/16” portion a tight fit in the motor shaft keyway.
I'm sorry, I don't fully understand. Don't forget, I'm not totally familiar with using a mill. And equally important, I don't have a fully functional mill just yet - only an old mill/drill that isn't very rigid and doesn't have very accurate xy dials or screws. Creeping up on optimum isn't so easy.......
Anyway, I think that you are referring to the concern that since the key is tightened using Allen stubs in the pulley, that the key needs to be able to be tightened into the bottom (flat) of the motor keyway, not the top edges of the motor keyway which are sharp and will wear the key too easily.......????
In other words, I think you are suggesting make the 3/16 section on the taller side of perfect and the 7mm section on the shorter side of perfect so the key can be tightened on the flat of the motor Keyway, not the edges?
Lastly, I think I can actually use the BP now. Some of the parts are still missing, and my order for them is prolly a week away. But I could clean off the bed and use it despite the missing parts......
A few questions
1. Since I don't have a quill wheel on either mill yet to fine tune the cutting height, am I better off lowering/raising the knee instead? Is there a better way?
2. What size cutter would you use to cut a stepped key?
3. What speed would you use? And would you climb cut or push cut? On my mill drill I really only have two speeds (low and high) but the direction and speed dramatically affect consistency, accuracy, burrs, and finish even without usable adjustment and feed wheels.
Ya, even asking those questions hurts a bit. I am SOOOOO green.... And SOOOOO eager to learn....
Anyway, I think that you are referring to the concern that since the key is tightened using Allen stubs in the pulley, that the key needs to be able to be tightened into the bottom (flat) of the motor keyway, not the top edges of the motor keyway which are sharp and will wear the key too easily.......????
In other words, I think you are suggesting make the 3/16 section on the taller side of perfect and the 7mm section on the shorter side of perfect so the key can be tightened on the flat of the motor Keyway, not the edges?
Lastly, I think I can actually use the BP now. Some of the parts are still missing, and my order for them is prolly a week away. But I could clean off the bed and use it despite the missing parts......
A few questions
1. Since I don't have a quill wheel on either mill yet to fine tune the cutting height, am I better off lowering/raising the knee instead? Is there a better way?
2. What size cutter would you use to cut a stepped key?
3. What speed would you use? And would you climb cut or push cut? On my mill drill I really only have two speeds (low and high) but the direction and speed dramatically affect consistency, accuracy, burrs, and finish even without usable adjustment and feed wheels.
Ya, even asking those questions hurts a bit. I am SOOOOO green.... And SOOOOO eager to learn....
Another question:
When I skimmed out the pully bore on my lathe to fit the motor shaft, I aligned the pulley on the grooves using a V-Block. I had noticed that it wobbled a bit on the old motor. So I reasoned that it was more important for the grooves to run true than the pully itself. It sure did spin beautifully on the lathe after that, so it must have been the bore that was out originally. It must have been off center more than ever a wee bit cuz it didn't clean up all the way around. I'd like to improve the fit a bit but I'd prefer to avoid pressing in a Bushing, and even more importantly cutting a new keyway. Anybody here have any experience using Loctite 635 on the motor/pully shaft and bore to improve the fit? I've used it successfully on farm machinery repair but never on a higher speed application like a motor mounted pulley. But that is exactly what the stuff is for.
When I skimmed out the pully bore on my lathe to fit the motor shaft, I aligned the pulley on the grooves using a V-Block. I had noticed that it wobbled a bit on the old motor. So I reasoned that it was more important for the grooves to run true than the pully itself. It sure did spin beautifully on the lathe after that, so it must have been the bore that was out originally. It must have been off center more than ever a wee bit cuz it didn't clean up all the way around. I'd like to improve the fit a bit but I'd prefer to avoid pressing in a Bushing, and even more importantly cutting a new keyway. Anybody here have any experience using Loctite 635 on the motor/pully shaft and bore to improve the fit? I've used it successfully on farm machinery repair but never on a higher speed application like a motor mounted pulley. But that is exactly what the stuff is for.
Correct, in both cases.
Answers to your questions:
1) yes, use the knee to feed up. Since you are new to the machine and perhaps unsure of it‘s accuracy on the dials, use a dial indicator on a mag base to confirm your up-feed.
2) any size that is wider than the step you are about to cut. Probably as small as a 1/4” would do, but it would be “flimsy” and would require a lot of care not to snap it off. I would use a good, sharp 1/2” end mill.
3) 1200 rpm. Do the right to left pass on the back side of the part; the left to right on the front side. This way you will always be feeding into the cutter (conventional milling). This is again just to make sure there are no surprises since the machine is new to you. I go both ways on my BP - it is old, but still very tight and accurate, so I get away with climb milling. Again use an external dial indicator on a mag base to control the step overs until you know if you can trust your dials.
I am not familiar with Loctite 635. Seems to be some sort of high build product which takes up space between parts.
Yes, the bore and the V grooves need to run true to each other - just the way you turned the pulley now. The biggest advantage of over boring and then bushing the pulley would be that now you can cut the 3/16” key way. No need for a stepped key any more. You can broach a key way easily enough on the BP, you just need to make yourself a little cutting tool. It will be slow, but works very well, I presume the pulley is cast iron.
OK, makes sense.
OK. I have several nice sharp 1/2 end mills.
OK. Goes against my instincts but yours is the voice of experience. I'll take that voice any day all day.
I could always cut a new Keyway 60 degrees away from the old one without Bushing the pulley....... And maybe someday I will.
Yes, it's cast iron. I have no idea how to broach on a mill just yet. I'll have to do some research first.
Thanks for all the great answers. Seems I have a LOT to learn.
mild steel: 1200 rpm is the number I pull out of a table I use. If you have a 2 flute end mill, reduce the feed rate but keep the speed. Conditions may vary depending on machine rigidity, coolant and other factors.
Just out of curiosity, what speed you have used?
When I said it goes against my instincts, I meant push instead of climb goes against my instincts. And only because the mill has so much backlash. I don't want the key growing or shrinking because some freeplay got taken up.
I have always assumed that milling probably uses the same surface speed recommendations as turning on a lathe. But I've never worried about it because my mill/drill only has 2 speeds - fast and slow. I usually use slow. If it chatters too much or the finish is rough, I use high. If it complains or squeals too much I use slow.
When I said I was green at milling, I really wasn't kidding.......
But I'm pretty darn good on my lathe so I'm hoping some of the methods and data are transferable.
Sorry @Susquatch, I got the milling direction completely a$$ backwards in my reply to your question 3) above.
To conventional mill, the cutter needs to be in the front of the workpiece (to cut the front step the key) when the table is moving right to left; and on the rear (to cut the rear step) when the table goes left to right.
Yes, you do want to feed into the cutting edge - that way the backlash is not a factor as it is taken out.
In machines with substantial backlash, the preference is not to climb mill (feeding in the same direction as the cutting edge is going) because if it grabs and takes up the backlash, the amount of material that needs to be removed at that instant may overpower the cutter and damage it off. Climb milling does tend to leave a better finish though.
To conventional mill, the cutter needs to be in the front of the workpiece (to cut the front step the key) when the table is moving right to left; and on the rear (to cut the rear step) when the table goes left to right.
Yes, you do want to feed into the cutting edge - that way the backlash is not a factor as it is taken out.
In machines with substantial backlash, the preference is not to climb mill (feeding in the same direction as the cutting edge is going) because if it grabs and takes up the backlash, the amount of material that needs to be removed at that instant may overpower the cutter and damage it off. Climb milling does tend to leave a better finish though.