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good tip on the thread handedness, that's an easy one to remember 
-
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KO-Lee Cutter/Grinder Revamp
- Thread starter Ray C
- Start date
- Joined
- Nov 16, 2012
- Messages
- 5,596
OK, we're making-up for lost time now...
When I made grinder hubs in days gone by, I would always take the raw (warped part), bore a basic hole then bore the taper. I always would make an arbor shaft with the same taper then, finish all the dimensions by spinning on the tapered arbor. Well, that's basically what I did here but I just used the actual shaft.
Pictures are worth a thousand words. Remember now, this hub was hardened. I don't remember for sure but think it's at RC 35 or so. Also, sorry but, I forgot to take pictures of boring the taper. I stuck the raw/warped piece in the 6 jaw with the disk (back) part facing the carriage. The taper was cut from the large diameter to the small diameter, as the cutter moved from right to left.
The good thing about doing it this way, is that the centerline is the reference axis for the completion of the entire part. Once setup like this, you can get the spindle shaft and all sides of the back plate all in one shot. Totally ideal situation. (I've made dozens of hubs this way).
The only thing I'm a little disappointed about, is the small welding void. It was not an inclusion but rather, I just had a couple low spots in the filler. I didn't want to chase it out on the lathe because it's only a cosmetic error.
Upon measuring this thing in every possible way, it is Dead-Ba11z-On.
Only a few more features to go which I'll catch some other day. It needs LH threads and I need to make the pushplate and LH nut.
Ray
When I made grinder hubs in days gone by, I would always take the raw (warped part), bore a basic hole then bore the taper. I always would make an arbor shaft with the same taper then, finish all the dimensions by spinning on the tapered arbor. Well, that's basically what I did here but I just used the actual shaft.
Pictures are worth a thousand words. Remember now, this hub was hardened. I don't remember for sure but think it's at RC 35 or so. Also, sorry but, I forgot to take pictures of boring the taper. I stuck the raw/warped piece in the 6 jaw with the disk (back) part facing the carriage. The taper was cut from the large diameter to the small diameter, as the cutter moved from right to left.
The good thing about doing it this way, is that the centerline is the reference axis for the completion of the entire part. Once setup like this, you can get the spindle shaft and all sides of the back plate all in one shot. Totally ideal situation. (I've made dozens of hubs this way).
The only thing I'm a little disappointed about, is the small welding void. It was not an inclusion but rather, I just had a couple low spots in the filler. I didn't want to chase it out on the lathe because it's only a cosmetic error.
Upon measuring this thing in every possible way, it is Dead-Ba11z-On.
Only a few more features to go which I'll catch some other day. It needs LH threads and I need to make the pushplate and LH nut.
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
OK, the fun begins on some of the other parts.
We're going to start on the front bearing cap. Here it is. If you'll recall, it was 1045 and heat treated to somewhere in the RC 30 range. In all honesty, I forgot exactly where it was set to but, for a part like this, somewhere about 35RC would be good. That is very pleasant to work on and gives an attractive and durable finish. When I say pleasant to work with, my real message is that it cuts evenly, cleanly and predictably. We're going to need that when get to a couple critical dimensions for the slight negative tolerance bearing fit.
The first thought, is how to chuck it up. I always consider two things: 1) Where are the critical dimensions and 2) how many features can be addressed w/o needing to remove the part from the chuck.
Here's the profile of the part and it's pretty clear that I can catch the back of the plate (right side of the drawing), the side of the plate and all of the various bore diameters w/o needing to remove the part. It's important for all those features to be concentric and the right side back needs to be perpendicular to the axis of the bore. On the left side of the diagram, the outer surfaces are not critical because they will not prevent the shaft from being perfectly straight during the assembly process.
Anyhow, for this piece, it's pretty obvious how it should be held. The point is, not all pieces are this obvious! It's really easy to ruin the elegance on the execution of a part if you box yourself into a corner and need to re-chuck it while in the midst of critical cuts.
So, without further delay, we start making chips... It cuts wonderfully and the machine sounds and feels great during the cut. It's what we strive for and it's nice when things go our way. Here's the very first pass on the backside; just enough to remove the scale. The next pass will look like chrome. The outer edge was taken to the final diameter and that's some pretty sexy looking metal under that first 1/8" of outer surface.
It's late now and we'll do more this weekend...
Ray
We're going to start on the front bearing cap. Here it is. If you'll recall, it was 1045 and heat treated to somewhere in the RC 30 range. In all honesty, I forgot exactly where it was set to but, for a part like this, somewhere about 35RC would be good. That is very pleasant to work on and gives an attractive and durable finish. When I say pleasant to work with, my real message is that it cuts evenly, cleanly and predictably. We're going to need that when get to a couple critical dimensions for the slight negative tolerance bearing fit.
The first thought, is how to chuck it up. I always consider two things: 1) Where are the critical dimensions and 2) how many features can be addressed w/o needing to remove the part from the chuck.
Here's the profile of the part and it's pretty clear that I can catch the back of the plate (right side of the drawing), the side of the plate and all of the various bore diameters w/o needing to remove the part. It's important for all those features to be concentric and the right side back needs to be perpendicular to the axis of the bore. On the left side of the diagram, the outer surfaces are not critical because they will not prevent the shaft from being perfectly straight during the assembly process.
Anyhow, for this piece, it's pretty obvious how it should be held. The point is, not all pieces are this obvious! It's really easy to ruin the elegance on the execution of a part if you box yourself into a corner and need to re-chuck it while in the midst of critical cuts.
So, without further delay, we start making chips... It cuts wonderfully and the machine sounds and feels great during the cut. It's what we strive for and it's nice when things go our way. Here's the very first pass on the backside; just enough to remove the scale. The next pass will look like chrome. The outer edge was taken to the final diameter and that's some pretty sexy looking metal under that first 1/8" of outer surface.
It's late now and we'll do more this weekend...
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
Only a few more baby steps on the front bearing housing today as I got a late start. It was almost one of those days where I was going to stay out of the shop but, decided to jump in and let the shop work take my mind off the earlier part of the day. The trick worked.
I'll tell y'a, digging these grooves is a bit of a white-knuckle operation -but it had a happy ending.
The O-Ring fits.
I did all the other features before the O-ring groove. That very first lip that looks like an accidental dig in the part, is actually a clearance area so the bearing can be lined-up before being pressed in. It's called-out in the diagram.
Despite what I though was going to be a dicey day in the shop, all the dimensions came out really well. Everything cleaned-up with just a few moments of clean-up with emery cloth. Wheeew! I've gotten to the point that it's pretty rare for me to over-shoot a dimension (although it does happen once in a while). It's usually a question of "will it take 30 seconds of emery cloth or will it take 3 minutes of emery cloth to bring it to size"... Luck was on my side today.
BTW: That little step all the way inside the bore is clearance for the bearing cage.
After this, we'll do the other side. No critical dimensions there. FWIW, when I design these things, I do not put formal tolerance specs in the drawings. The only place that tolerances are specified are for where it's really needed such as bearing race fitments, intentional interference areas etc. I self-imply that all other tolerances are +/- 1 thou and I don't cry or beat myself up if I blow it a little. Sometimes, I try to nail non-critical dimensions dead-on only for the practice of doing it. I tend to do that on about 1/3 of the non critical dimensions -but it varies from project to project. It's good practice but can really slow you down.
I'll tell y'a, digging these grooves is a bit of a white-knuckle operation -but it had a happy ending.
The O-Ring fits.
I did all the other features before the O-ring groove. That very first lip that looks like an accidental dig in the part, is actually a clearance area so the bearing can be lined-up before being pressed in. It's called-out in the diagram.
Despite what I though was going to be a dicey day in the shop, all the dimensions came out really well. Everything cleaned-up with just a few moments of clean-up with emery cloth. Wheeew! I've gotten to the point that it's pretty rare for me to over-shoot a dimension (although it does happen once in a while). It's usually a question of "will it take 30 seconds of emery cloth or will it take 3 minutes of emery cloth to bring it to size"... Luck was on my side today.
BTW: That little step all the way inside the bore is clearance for the bearing cage.
After this, we'll do the other side. No critical dimensions there. FWIW, when I design these things, I do not put formal tolerance specs in the drawings. The only place that tolerances are specified are for where it's really needed such as bearing race fitments, intentional interference areas etc. I self-imply that all other tolerances are +/- 1 thou and I don't cry or beat myself up if I blow it a little. Sometimes, I try to nail non-critical dimensions dead-on only for the practice of doing it. I tend to do that on about 1/3 of the non critical dimensions -but it varies from project to project. It's good practice but can really slow you down.
- Joined
- Nov 16, 2012
- Messages
- 5,596
As promised, we're doing the other side. Once again, a little thought goes into how this should be held. If absolute, perfect concentricity were needed on the outside dimensions, I would build a a mandrel of some sort and spin it on the same axis as the bore. No need for that here.
We'll need to carefully hold this one with a partial bite from the chuck. This will be a good test of the new 6 Jaw chuck. The chuck was purchased specifically for parts like this.
Look closely... machinist parallels were placed against the chuck (between the jaws) and the part pressed flat against them. This is good enough in this case. CAUTION: Remove the parallels from the chuck before spin-up. They will go flying just like a chuck key.
The TIR was checked on the outer lip and the exposed bore. I did in-fact need to loosen the chuck bolts and bump the body a tiny bit. The difference TIR between the two surfaces was adjusted well within 1/2 thou by bumping the chuck body. -Close enough!
There it is, fresh naked metal to behold.
IMPORTANT: With the part held this way, all the cuts must be fairly light. A heavy cut could dislodge the part from the chuck -not good!
FYI: The part is on the order of 2.5 to 3.5" diameter. The lathe was set to base RPM of 360 and the VFD was used to tweak speeds up/down as needed. Feed rates were around 2 thou/rev and DoCs were kept around 20-25 thou.
All done except the holes. ...And a big Hooray for the 6 jaw chuck. Not the slightest bit of damage or scratching on the part.
The piece came out very nicely. I happen to set it down (gently) on the granite table and it sits nice and flat and almost has that nice "suction" feel when it's lifted off the plate.
OK, I'm going to knock the other one out quickly and there won't be any write-up because it's almost the same part. Obviously, I'm writing this up in hopes that someone new to this gets a feel for how to make this kind of stuff.
Later...
Ray
We'll need to carefully hold this one with a partial bite from the chuck. This will be a good test of the new 6 Jaw chuck. The chuck was purchased specifically for parts like this.
Look closely... machinist parallels were placed against the chuck (between the jaws) and the part pressed flat against them. This is good enough in this case. CAUTION: Remove the parallels from the chuck before spin-up. They will go flying just like a chuck key.
The TIR was checked on the outer lip and the exposed bore. I did in-fact need to loosen the chuck bolts and bump the body a tiny bit. The difference TIR between the two surfaces was adjusted well within 1/2 thou by bumping the chuck body. -Close enough!
There it is, fresh naked metal to behold.
IMPORTANT: With the part held this way, all the cuts must be fairly light. A heavy cut could dislodge the part from the chuck -not good!
FYI: The part is on the order of 2.5 to 3.5" diameter. The lathe was set to base RPM of 360 and the VFD was used to tweak speeds up/down as needed. Feed rates were around 2 thou/rev and DoCs were kept around 20-25 thou.
All done except the holes. ...And a big Hooray for the 6 jaw chuck. Not the slightest bit of damage or scratching on the part.
The piece came out very nicely. I happen to set it down (gently) on the granite table and it sits nice and flat and almost has that nice "suction" feel when it's lifted off the plate.
OK, I'm going to knock the other one out quickly and there won't be any write-up because it's almost the same part. Obviously, I'm writing this up in hopes that someone new to this gets a feel for how to make this kind of stuff.
Later...
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
A few more pieces of the puzzle to show here.
Here's the rear bearing housing; very similar to the front housing...
And now for the the pieces of the center housing. Started out making two flanges and cutting the oil seal groove that mates with the bearing housings. It's too hard to dig a 1/8" groove on just one of the pieces so, we'll dig roughly half on each side. Can't remember for sure but, the depth is about 15 or 20 thou shy of 1/8" to compress the seal.
The center body is a piece of schedule 80 pipe. Cutting to rough size and will trim to precise length on the lathe.
Putting a taper on the end for a weld groove.
Here it is just roughly setup as a sanity check.
Coming up:
That's a rap for today...
Ray
Here's the rear bearing housing; very similar to the front housing...
And now for the the pieces of the center housing. Started out making two flanges and cutting the oil seal groove that mates with the bearing housings. It's too hard to dig a 1/8" groove on just one of the pieces so, we'll dig roughly half on each side. Can't remember for sure but, the depth is about 15 or 20 thou shy of 1/8" to compress the seal.
The center body is a piece of schedule 80 pipe. Cutting to rough size and will trim to precise length on the lathe.
Putting a taper on the end for a weld groove.
Here it is just roughly setup as a sanity check.
Coming up:
- Drill the 6-hole patterns in all the flanges.
- Tap the two flanges for the center piece.
- Clean the scale off the pipe in the sandblaster.
- Weld the flanges to the tube.
- Toss it in the lathe, true it up and take it to final size.
That's a rap for today...
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
Here's where we are after a few hours in the shop... Sticking to the plan with only a minor detour.
All 4 of those flanges needed drilling and 2 of them drilled & tapped. Fortunately, the mill has DRO with the bolt/circle function which is right up there with sliced bread, food, water and oxygen.
And yes, I can understand why you might think otherwise but, I do in-fact own a mill. This is one of Matt's early machines.
... A few close-ups. By the way, I really like that Shars dial caliper. They have 2 versions; one is the base model and this one is a step-up.
Lot's of tapping... By the way, that tap handle is my favorite style. Here's a thread from 4-5 years ago that gives a blow-by-blow on how to make them: https://www.hobby-machinist.com/threads/my-favorite-tap-handle.20186/#post-172788
Here's where things deviated a little bit... I didn't want to bore the inside of the pipe but, the sandblaster just wasn't doing the job at getting the inside clean. The boring bar got the job done. Didn't take too long and only a few thou was taken off. Also, I happen to notice that the pipe was amazingly straight and had an even surface on the inside. It didn't think it was DOM pipe but it sure was good quality. I didn't think it was possible for schedule 80 to be Drawn Over Mandrel.
Now for welding... The scale and grease were cleaned way back from the weld zone. That's very important with TIG. Fumes burning off of nearby slag, oil, scale etc will mix with the argon gas and screw-up your bead in a heartbeat. The pipe and flange were pre-heated to about 500F.
On one side, I did a basic TIG. I have no idea what metal the Schedule 80 is but, the flange is 1045. Of course, filler selection is critical so, I did the right thing and used the most appropriate one for the job... The cheapest stuff I had! -Which happens to be 70S2. (For a job like this, coat hanger wire would work fine).
So, everybody likes this "Walking The Cup" technique. This is the first time I ever tried it -and as you can see, it will probably be my last. Darn near set my fingers on fire. Way too much motion and thinking going on. I'll stick with the boring jab & dab style.
So, the center piece is sitting in the heat treat oven at 600F and I'll gradually cool it down over the next several hours. That 1045 connected to a big thermal sink (hollow tube) will self heat treat at the junction in a heartbeat. Pictures of that will come in a few hours after it transitions through the "Martenizing" phase.
There you have it for a few hours... Any thoughts, comments, questions, stock tips etc?
Later
Ray
All 4 of those flanges needed drilling and 2 of them drilled & tapped. Fortunately, the mill has DRO with the bolt/circle function which is right up there with sliced bread, food, water and oxygen.
And yes, I can understand why you might think otherwise but, I do in-fact own a mill. This is one of Matt's early machines.
... A few close-ups. By the way, I really like that Shars dial caliper. They have 2 versions; one is the base model and this one is a step-up.
Lot's of tapping... By the way, that tap handle is my favorite style. Here's a thread from 4-5 years ago that gives a blow-by-blow on how to make them: https://www.hobby-machinist.com/threads/my-favorite-tap-handle.20186/#post-172788
Here's where things deviated a little bit... I didn't want to bore the inside of the pipe but, the sandblaster just wasn't doing the job at getting the inside clean. The boring bar got the job done. Didn't take too long and only a few thou was taken off. Also, I happen to notice that the pipe was amazingly straight and had an even surface on the inside. It didn't think it was DOM pipe but it sure was good quality. I didn't think it was possible for schedule 80 to be Drawn Over Mandrel.
Now for welding... The scale and grease were cleaned way back from the weld zone. That's very important with TIG. Fumes burning off of nearby slag, oil, scale etc will mix with the argon gas and screw-up your bead in a heartbeat. The pipe and flange were pre-heated to about 500F.
On one side, I did a basic TIG. I have no idea what metal the Schedule 80 is but, the flange is 1045. Of course, filler selection is critical so, I did the right thing and used the most appropriate one for the job... The cheapest stuff I had! -Which happens to be 70S2. (For a job like this, coat hanger wire would work fine).
So, everybody likes this "Walking The Cup" technique. This is the first time I ever tried it -and as you can see, it will probably be my last. Darn near set my fingers on fire. Way too much motion and thinking going on. I'll stick with the boring jab & dab style.
So, the center piece is sitting in the heat treat oven at 600F and I'll gradually cool it down over the next several hours. That 1045 connected to a big thermal sink (hollow tube) will self heat treat at the junction in a heartbeat. Pictures of that will come in a few hours after it transitions through the "Martenizing" phase.
There you have it for a few hours... Any thoughts, comments, questions, stock tips etc?
Later
Ray
- Joined
- Nov 16, 2012
- Messages
- 5,596
We're getting there...
The heat-up and cool-down worked great. The 1045 flange plates ended-up being about the same hardness as the other two pieces. Very easy to work with; has a nice clean, snappy feel when it cuts. I've made the mistake of work-hardening or weld-hardening things and that can be a real problem.
Just cleaning-up the surfaces here. Hardly taking anything off to speak of.
The welding caused a small amount of warpage; not much, but enough that a light pass was needed and the grooves adjusted accordingly.
It's taking shape... What'ya think, should I toss it in the luggage, grab the passport and see which of the FVEYs stops me at Customs? Hello, State Department, this is Ray C. Can you come and help me?
Look Ma, all the holes line up!
We're over the hump I think. OK, that's about it for now...
Regards
Ray
The heat-up and cool-down worked great. The 1045 flange plates ended-up being about the same hardness as the other two pieces. Very easy to work with; has a nice clean, snappy feel when it cuts. I've made the mistake of work-hardening or weld-hardening things and that can be a real problem.
Just cleaning-up the surfaces here. Hardly taking anything off to speak of.
The welding caused a small amount of warpage; not much, but enough that a light pass was needed and the grooves adjusted accordingly.
It's taking shape... What'ya think, should I toss it in the luggage, grab the passport and see which of the FVEYs stops me at Customs? Hello, State Department, this is Ray C. Can you come and help me?
Look Ma, all the holes line up!
We're over the hump I think. OK, that's about it for now...
Regards
Ray
- Joined
- Jun 7, 2013
- Messages
- 10,450
As to the directions of spindle and lead screw, not so in all cases; The Regal Leblond lathes have left hand lead screws, so when cutting right hand threads, the spindle and lead screws are rotating in opposite directions; why they designed it that way, I have no idea.
- Joined
- Nov 16, 2012
- Messages
- 5,596
I'll be darned... I wonder if they're all that way or just some models. I ran my dad's LeBlond for the better part of 15 years. It was a 15-54 gearhead (non-servo) but for the life of me, I can't recall if it was LH or RH leadscrew.
Ray