As per the Tormek instruction book I always replace my sg-250 wheel when the stone gets to about 200mm. Over the years I have accumulated a lot of stones in this category.
Occasionally, I will fit one on my Tormek to sharpen a large cleaver or double axe. Other than that I have not found any other suitable use for them. Considering the cost of these wheels I was hoping to hear some ideas of how to use them beyond the Tormek recommended wheel life. Thanks for your input.
Ken,
Is the width of the SG-200 the same as the SG-250 or is it thinner?
Elden,
The width of the SG-250 (and all 250 wheels, meaning having a diameter of 250mm or just under ten inches) is 50mm, or just under two inches.
The width of the SG-200 (grinding wheel for the T 3 and T4) is 40mm, or somewhere around an inch and a half.
Ken
I put a query a while ago about this to Tormek, hoping that I could buy a T4 and continue using the T2000's stone until the stone was no longer useful. What I got back was that the stone is about 9mm wider on the T2000 (or T7), and wouldn't fit onto the T4.
It would be great if we could use a worn Sx250 stone on the T4, getting more value for the cost of the stones.
Plus, I would use the T4 for only flat-ground tools. I am a woodturner, and sharpen mostly gouges. The stone on the T2000 gets lots of groves where it isn't smooth across. By having a stone dedicated to flat tools (skews, scissors, knives, etc.), I could also extend the Sx250 stone's life (as I wouldn't have to flatten it as often using the diamond truer).
I brought this up before and was shot down, by the size issue.
So let me go at this from another perspective......
While the duty cycle isn't the same on the T4's motor, does it have the same power as the T7's? If the same power, where one is not going to easily burn it up, or do this all the time (consider even a lighter duty cycle), then couldn't one replace the T4's shaft, with the T7's shaft and swap the stone over? (my understanding is they are the same diameter)
Randal (SADW),
Your thoughts are running close to where mine are. I do not think I would want to use a full sized SG-250 even if it would fit, however. But if it were worn to 200mm, would it work if it had the T-7 shaft? If it would, I think the US bar would have to changed as well.
Several things to answer here:
I think we need to ask two questions:
1) Is it possible?
2) Is it practical?
Without disassembling either my T7 or T4, I measured the length of the two shafts. The length is about the same. The threads are the same 12mm at either end. I don't know if it would be possible to switch out the shaft in the T4 for the T7 shaft. I imagine Stig can answer this. The other constraint, and I have not checked this, is that getting the water trough to work might require some minor jury rigging.
Both the T7 and T4 have approximately the same flat area on the side of the wheel. Both have approximately 50mm or two inches at full diameter. (Yes, I know the diameter is different.) A 250mm wheel worn down to 200mm will have only half the flat area (25mm or one inch).
For the cost of a T4, one could purchase two replacement SG-250 grinding wheels.
For not much more than the cost of a second T7 shaft, one could purchase a replacement wheel (SG-200)
The minimum size constraint with wheel wear is keeping the wheel wet. Again, this could be jury rigged.
I wish Tormek would forget the 50% motor duty. The operator will tire long before the motor. I suspect the 120 watt T4 motor could drive a larger wheel, if one really needed to do that. The T7 has a 200 watt motor with more than enough power.
Tormek recommends only using the side of the wheel for flattening plane blade and chisel backs. This seems logical. However, the general taboo about using the side of the grinding wheel, even though almost everyone does, pertains to much narrower wheels driven at much higher speeds. I do not see it as an issue with the Tormek.
My wheels are flat. I have not tested flattening the side of the wheel. If we look at the use of the platform tool rest (SVD-110), if a grinding wheel dressing stick is placed where the hand scraper is placed, it should be easy to correct any out of flat condition.
The universal support bar would not need to be repositioned. Tormek has very cleverly placed the sleeves such that even the knife jigs work identically.
To answer the two questions, in my opinion, this is all possible. I think it is more practical and less costly to just replace the wheel when it is worn down.
Ken
Ken,
In answer to part of your questions, I do not think this would be specifically a reason to go out and buy the T4, but I do think if one had already bought it (for portability purchases), then one would already have the other shaft, water tray, etc. to try.
I view this as a way to expand stone use, and for special projects (like the cleavers which has been mentioned).
Also, what do you consider "about the same"? Is 1cm about the same?
SADW,
Good points.
I had not considered someone (like me....) who already has both models. I should disassemble both and see if the T7 shaft will fit with the T4. I do not see motor capacity as a real issue for occasional use.
I made a quick measurement of the width of the flat portion of the sides of the two wheels. With full diameter remaining, both wheels have two inches. If the SG-250 is worn to 200 mm or eight inches, the flat plane is only one inch.
Good thinking outside the box, SADW.
Ken
A new T-4 is $400 (at Amazon ... Just a quick check). And the SG-200 stone is $130.
So, if I could buy a T-4 with no stone, but with a T-7 shaft, I could have a machine for about $270 that would be able to continue using the stones that no longer fit on my T-2000/T-7.
I would end up with two machines for $85 more than a single machine with two stones (the SG-250 is $185).
And that difference goes down if we talk about "handing down" an SB-250 ($270-$190=$60) and I save money with an SJ-250 ($270-$385=$115).
To me, this is a good deal !
Rich,
Please go very slowly. I think you are about to make an expensive mistake.
Before believing Amazon's many prices, check with a couple regular Tormek dealers. I don't care who gets your business. Affinity Tool is the US importer. Their prices are the legitimate Tormek prices. Sharptoolsusa is a very reliable business, also.
The list price for an SG-200 is $109. You should be able to get a new T4 from many dealers for $399, including shipping.
I do not think you would actually be able to implement your math plan.
Your most cost effective choice is to order a new SG-250 for $184 and not worry about your present wheel.
If your wheel, whether a new or old wheel, has grooves worn in it, you need to dress it with a TT-50 truing tool. It costs about $89. If, by chance, you have the older model, you can get a TT-50U for around $56. It is the jig minus the diamond cluster. You reuse your present diamond cluster with it.
For future reference, you should true the stone long before grooves develop.
With a new SG-250 and a proper truing tool, you should be in business for a long time. The same grinding wheel will easily sharpen your tools, including flat sharpening on the side.
Do continue posting.
Ken
Rich,
Ken raised some valid concerns.
One of them was, will T-7 shaft work on the T-4? I was alluding to that in my use of "would it work if it had the T-7 shaft?". I don't know if it would fit the T-4. I am guessing that the length of the two shafts are not the same length, but I don't know that as a fact. One would need to know these things before pursuing the idea.
If perchance the shaft would work, then the cost issue presents itself. There is the shaft and the Universal Support bar. Will the T-4 trough work? If not, can the T-7 trough be adapted?
Ken mentioned that the T-7 wheel can be used down smaller than 200mm. That is true. My wheel is under 200mm. I do remove the honing wheel to allow more clearance. The trough can be raised higher by using boards, etc. under it.
Am I back pedaling? Maybe... Ken said go slowly. I agree caution is in order. I had a high school teacher who told us, "Think about it for 5 or 10 years." I guess that is a little bit too long for this situation, but you get the idea! ;)
I think there is something being overlooked here. Tormek recommends not using the stone when it gets to 200 mm or less in diameter. Maybe something was lost in the translation here. After all, in the great T4 vs T7 debate I brought this size difference up. The T4 wheel begins life at 200mm. I asked Jeff Farris when he quit using wheels and his response is lost to me now but it seems that it was even less than 200mm. It does not matter what machine it is mounted on, it is still 200 mm in diameter. So, the real reason you have to dump the wheel is the greater concavity of the grind. The smaller the wheel, the greater the curve on the edge, the weaker that edge becomes. You go from razor sharp to broken edge in a hurry. I do not know how handy you are but F Dick knife sharpeners and some others use two stones grinding towards each other to sharpen them. The knife edge is placed into the "valley" between the two wheels. If you could rig this sort of contraption up you would have a superlative knife sharpener.
Quote from: jeffs55 on January 22, 2016, 05:46:39 AM
I think there is something being overlooked here. Tormek recommends not using the stone when it gets to 200 mm or less in diameter. Maybe something was lost in the translation here. After all, in the great T4 vs T7 debate I brought this size difference up. The T4 wheel begins life at 200mm. I asked Jeff Farris when he quit using wheels and his response is lost to me now but it seems that it was even less than 200mm. It does not matter what machine it is mounted on, it is still 200 mm in diameter. So, the real reason you have to dump the wheel is the greater concavity of the grind. The smaller the wheel, the greater the curve on the edge, the weaker that edge becomes. You go from razor sharp to broken edge in a hurry. I do not know how handy you are but F Dick knife sharpeners and some others use two stones grinding towards each other to sharpen them. The knife edge is placed into the "valley" between the two wheels. If you could rig this sort of contraption up you would have a superlative knife sharpener.
Jeff, last year there was a pretty passionate discussion "Hollow vs flat grinding thoughts" :) http://forum.tormek.com/index.php?topic=2413.45 concerning the common misconception that "a hollow ground bevel has a weaker edge than a straight ground one". The results were nicely summarised by Rob in the answer #52.
Jan
Eldon,
I'm not seeking to make a T4 with a T7 shaft, let's call it a T47. I am asking Tormek why they don't sell such a device.
As stated, I'm a woodturner so I sharpen gouges a lot on days I can spend turning. This makes groves in the stone. And when I have to sharpen tools that are occasionally used (skews, parting tools, etc.) the stone isn't flat enough. So, do I flatten the stone & sharpen, or work another way. Usually, the latter.
This seems like a better way than swapping out stones.
If I could buy a reasonably priced T47, and use stones that are otherwise useless (I.e., <200mm), this seems like a good idea.
Noted, many are advising caution. I'm not running out just yet to buy something, but I respect Tormek's leadership in the sharpening world & am interested in their experts' opinions of
We have a couple of issues here, and some confusion from the handbook. Page 155 of the latest edition of the handbook under Lifetime of the Stone states" "We recommend that the stone is changed before it wears down too much. You should not allow it to be less than approx. 180mm (7") in diameter in order to ensure a satisfactory grinding performance. The smaller T3 stone should not be less than 150mm (6")."
Elsewhere in the handbook, I believe there is a different recommendation for minimum size to be 200mm (8"). This is also the recommendation cited by Jeff55 as stated by Jeff Farris.
Unfortunately, neither the handbook nor Jeff Farris stated the reasons for this limit. I believe they have more to do with difficulty keeping the wheel wet than in having more hollow grind. The hollow grind issue is easily resolved by adding three degrees to the bevel angle.
There may be potential tool clearance constraints with smaller diameter grinding wheels. I am not sure of this.
Rich,
I believe your difficulty is from the surface of your grinding wheel, not its diameter. I have frequently referred to the grinding wheel as consumable, but lasting a long time, like brake discs on a car. Some tools will wear the wheel more quickly, just like driving in the mountains will cause more wear on the brakes than driving on flat roads. Gouges localize the wear on the grinding wheel. Therefore, the wheel needs to be trued more often. It will wear more quickly. It is the nature of the tool.
With your T200, have you upgraded to the new model (TT-50) of the truing tool and the micro adjust version of the universal support? I realize you prefer to be turning rather than sharpening and truing your wheel. However, you cannot expect top performance from your tools unless your grinding wheel is true. The key is early and frequent light truing. the upgraded jigs and accessories really do make this easier to do.
I do not see Tormek ever making a T47. There are too many good business reasons against it. However, you could have one made by a local machine shop. (We have not yet resolved whether or not the T7 shaft will work with the T4.) If it is not compatible, all you would need to do is take your T4 shaft to a local machine shop and ask them to make one with ten millimeters more on the wet wheel end. You could reduce your cost by having them make it with non stainless steel and reverting to the old right hand thread on the wet end. Bring your wallet, this may cost almost as much as the T4. You would need to modify the water tray as well.
I do not think this is practical. As I stated earlier, I believe your best course of action is to procure a TT-50, micro adjust universal support, and a new SG-250. These should cost between $350 and $400. As an alternative, you might consider selling your T2000 and putting the proceeds toward a new T7. I believe that would cost less than $350.
Ken
Another option would be devising a way to trim the width of those old SG-250 grindstones down to 200 mm so they will fit on the T4.
I understand the "need" to find a use for things like those old worn grindstones that seem to have a lot of value left in them. It reminds me of a lesson I learned the hard way. One of my hobbies is speaker building. I had a pair of KLH-22A speakers that I had bought used when I was in college. Over the years I had ruined them by playing them too loudly and replacing blown drivers with whatever I could find to fit. That is a sure-fire way to produce a crappy sounding speaker because the crossover circuitry is designed to match, among other things, the electronic characteristics of the drivers.
In recent years I was finally learning the right way to approach issues like these, and I wanted to preserve those old KLH cabinets and restore the them to their former glory. It turns out that such a thing costs much more money than it's worth because everything would need to be redesigned from the bottom up around the cabinets themselves. So in the end I salvaged any parts I could from them and set them out by the curb for trash collection. The terminal plates with the KLH logo, along with the inductors from the crossover circuit, survive in a well-designed pair of speakers that now grace my classroom. They make great conversation pieces and they sound awesome.
(http://i1291.photobucket.com/albums/b553/htrivilino/IMG_0132_zps9g3k3xs5.png) (http://s1291.photobucket.com/user/htrivilino/media/IMG_0132_zps9g3k3xs5.png.html)
(http://i1291.photobucket.com/albums/b553/htrivilino/IMG_0083%20post_zpsl209wzqm.png) (http://s1291.photobucket.com/user/htrivilino/media/IMG_0083%20post_zpsl209wzqm.png.html)
Good thoughts, Herman. We do not stop learning when we reach adulthood. Your speakers remind me of my nice, very flat combination oilstone. I inherited it from my grandfather who probably bought it eighty years ago. It may well have been worn hollow when he bought it. I spent the effort to restore the old oilstone partly as a way to honor my grandfather, just like Jan did with his grandfather's mortise chisel.
In my case, the cost included essentially ruined a two hundred dollar diamond flat plate. My grandfather, a practical, thrifty man, would have questioned the wisdom of my efforts.
Ken
If I could buy a reasonably priced T47, and use stones that are otherwise useless (I.e., <200mm), this seems like a good idea.
It is more profitable to sell you the stone rather than a way to use a depleted stone. It is always about the money. On the other hand, if a business is not profitable it ceases being a business and becomes a government welfare agency.
Close, but not quite.
I disassembled my T4 and T7. The shaft from the T4 is slightly shorter than the T7 shaft. They do not interchange.
Going by the 170mm minimum diameter for the SG-250, by that point there is very little flat area remaining on the side of the wheel. As long as the water trough can be shimmed up enough to keep the wheel wet, the wheel should continue to be usable, although the hollow grind will be increasingly more pronounced.
I have not worn down a wheel that much. However, when my wheel gets down to the 220 to210mm range, I will start watching for a sale at my local dealer. I believe purchasing a replacement wheel when it is discounted is the most cost effective way to get the most value from a wheel. I realize many of us do not have the luxury of a local dealer.
As for a Tormek 47, it is definitely a pleasant luxury having two Tormeks. The jigs and accossories are inter hangeable between the two models. Whether it is logical to have one or two Tormeks depends on the intended use. I would have one up and running before even thinking of adding a second unit.
Should one opt for having two Tormeks, again, I would let the work be the deciding factor as to which model(s) to choose.
Ken
Quote from: Ken S on January 24, 2016, 11:37:22 PM
I disassembled my T4 and T7. The shaft from the T4 is slightly shorter than the T7 shaft. They do not interchange.
The lengths should differ by 10 mm (the difference between the widths of the 50 mm and 40 mm grindstones).
I thought the issue, though, was the diameters of the main shafts. If they match then it seems a T7 main shaft could be inserted in a T4 so an old 50 mm wide grindstone from a T7 could be mounted on a T4. Then you'd have to see of you could somehow mount a T7 water trough on a T4.
So what is the issue? The length or the diameter or both?
As long as the water trough can be shimmed up enough to keep the wheel wet, the wheel should continue to be usable, although the hollow grind will be increasingly more pronounced.
After the comma (,) says it all. The hollow grind becoming more pronounced is the reason for the size limit on the wheel, as I have tried repeatedly to make clear. At some point, you are just not going to have a usable edge. Of course you could literally be splitting hairs and use the stone but then, all you are doing is splitting hairs and of what use is that except in a demonstration of sharpness achievablilty. Splitting hairs is fine for demo purposes but show me where that edge can be sustained long enough in the real world to be of any use.
Jeff,
I agree with you about the hollow grind becoming increasingly intrusive with smaller diameter. I remember the quote from Jeff Farris. However, I do think it is unfortunate that Jeff did not include the reasons behind his statement.
Hollow grinding for cabinetmaking tools has been a long standing accepted and advocated practice. I do not recall anyone claiming it was superior to or equal to flat grinding, just that it is quicker and requires less work. The 1909 vintage Bedrock planes I pyrchased from the original owner came with a hollow ground edge. Most grinders, especially in home shops, used six inch wheels. The combination of hollow grinding and micro bevels (narrow secondary bevels which do the actual cutting) has been standard practice. Granted, this is a practical expedient.
Ken
So let me think out loud. If the edge becomes stronger and greater as shown in the following thread, a smaller grinding wheel will lead to an increase of the amount of metal behind the edge. Simply decrease the angle to get rid of the excess metal.
http://forum.tormek.com/index.php?topic=2413.0
Good thought, Elden. I fully agree with you. :)
Jan
One of the things which fascinates me with the Tormek is its versatility. In the case of chisels (and plane blades), the Tormek can easily be set to the standard twenty five degree bevel setting and essentially left there. It's a "no brainer" way to get consistently sharp edges with the same bevel angle. You can also custom fine tune with complete control. The choice is yours.
Ken
Quote from: jeffs55 on January 25, 2016, 05:38:02 AM
The hollow grind becoming more pronounced is the reason for the size limit on the wheel, as I have tried repeatedly to make clear.
But the T4 comes with a 200 mm diameter grindstone. So if that diameter grindstone is good enough on a T4 then it's good enough on a T7.
Quote from: Elden on January 25, 2016, 06:49:39 PM
If the angle becomes stronger and greater as shown in the following thread, a smaller grinding wheel will lead to an increase of the amount of metal behind the edge.
The angle stays the same, the tool gets stronger because of the extra metal on the heel. And that extra metal might get in the way when doing certain types of work such as carving. You could remove it with a grinder. That's not an elegant solution, but it's the one I'd go for in a pinch.
"But the T4 comes with a 200 mm diameter grindstone. So if that diameter grindstone is good enough on a T4 then it's good enough on a T7."
And, even a 200 mm wheel is almost 2" larger than your basic 6" bench grinder that a lot of folks use to sharpen stuff.
http://forum.tormek.com/index.php?topic=2413.msg12059#msg12059
Thank you, Herman, I am amending the term "angle" to "edge". :) That was my meaning, but I used the improper word.
After giving my other statement ("Simply decrease the angle to get rid of the excess metal.") more thought, I want to clarify what I mean. Lower the micro adjust on the US bar so that the heel of the tool will be reduced, forming a double bevel. It would not need to be reduced much, only enough to remove the extra metal left. This would result in a tool with a primary and secondary bevel, having the Tormek ground look.
Personally, I don't think it will really matter that much.
Jan, how many degrees difference will there be at the heel of a 6.35 mm thick tool, ground at 25°, using a 250mm diameter versus a 175mm diameter grinding wheel?
Quote from: Elden on January 26, 2016, 08:10:37 AM
Jan, how many degrees difference will there be at the heel of a 6.35 mm thick tool, ground at 25°, using a 250mm diameter versus a 175mm diameter grinding wheel?
Assuming a 6.35 mm thick chisel, ground at 25º we will get following figures:
a) for 250 mm grindstone the heel angle is 31.2º and hollow size is 0.18 mm,
b) for 175 mm grindstone the heel angle is 33.5º and hollow size is 0.24 mm.
So, the difference between the heel angles is slightly more than 2 degrees.
From the practical point of view the heel angle of a tool has nearly no effect on its performance, only the edge angle is important. :)
Jan
P.S.: The drawing shows the situation for 250 mm grindstone diameter.
Hatch shows the extra metal on the heel, which would be removed when grinding flat.
(http://img21.rajce.idnes.cz/d2102/11/11771/11771137_37021e568ec44478b9ce7dc74d286378/images/ELDEN-CHISEL_25_deg_125mm_700.jpg?ver=0)
Why not just set the jig for twenty eight degrees?
Regarding using six inch grinders, in my late dry grinder days, I used a Norton white wheel in my six inch grinder. The white wheel was more friable than the traditional gray wheels. Worn grains crumbled off more easily than with gray wheels. If I had not purchased my Tormek, my six inch white wheel would be a less than five inch wheel. Of course, I did the final sharpening with bench stones back then.
Ken
For your 5" grindstone diameter the hollow will increase to 0.31 mm which is not dramatic, but the heel angle will be more than 36° and similarly will increase the extra metal on the heel.
However, in my opinion, still fully functional chisel shape. :)
Jan
By the time the wheel is ground down to five inches, hopefully, a Tormek has appeared. Ken
The heel angle itself is not very important for tool performance, but it brings important lesson for freehand sharpeners.
When the edge would meet the grindstone at the heel level of the chisel (see the drawing in reply #31), than we would ground an edge angle 31.2° (using 250 mm stone) instead of the desired 25°.
In other words, when by freehand sharpening we drop the level on which the edge meets the stone by some 6 mm, we will increase the edge angle by 6.2°.
For 175 mm grindstone diameter this error will increase to 8.5°. And that's too much, that's not acceptable. ;)
Jan
Quote from: grepper on January 25, 2016, 03:46:46 AM
So what is the issue? The length or the diameter or both?
The issue is the diameter. Ken, will the T7 mainshaft fit in the T4? I realize the lengths don't match, but if the diameters do it can be done. Then you just attach an old 200 mm diameter grindstone from a T7 and see if the wider T7 trough will fit on the T4. It would be a good use for an old trough that got replaced with upgrade. And then ... wait for it ... Bob's your uncle!
Quote from: Ken S on January 26, 2016, 03:53:41 PM
Why not just set the jig for twenty eight degrees?
Because you want the edge angle to be 25°?
Herman,
The shafts of the T4 and T7 look almost identical. The problem is the part of the shaft inside the housing is slightly shorter with the T4. (The part of the shaft which holds the grinding wheel is also 10mm shorter.) Nice idea; it just doesn't work. And, I doubt it is cost effective. IMHO, the most cost effective solution is just to purchase a new grinding wheel. Keep the old one for the odd rough job.
The reason I suggested setting the jig for twenty eight degrees is to compensate for the approximately three degree hollow grind with the smaller diameter wheel.
As a side thought, using twenty five degrees for chisels is really a compromise. For delicate paring operations, an angle approaching twenty or fifteen degrees works better. For heavier work, or with A2 steel, thirty degrees works better.
Ken
Quote from: Ken S on January 27, 2016, 03:55:48 AM
As a side thought, using twenty five degrees for chisels is really a compromise. For delicate paring operations, an angle approaching twenty or fifteen degrees works better. For heavier work, or with A2 steel, thirty degrees works better.
The hardness of the wood makes a difference, too. As you know, I am not the most delicate of carpenters. Nothing fancy for me. If the wood is too hard I respond by hitting the chisel harder with my mallet. That will quickly chip the edge of a chisel in which case I simply add a micro bevel at a larger angle.
"Nothing fancy for me. If the wood is too hard I respond by hitting the chisel harder with my mallet"
:)
As Theodore Roosevelt said, "Speak softly and carry a big mallet." :)
Herman, I did not fully answer your question. Both the T4 and T7 shafts have the same diameter and threads. The lengths are slightly different, and the T4 has a cross pin. The T4 uses a standard nut on the leather honing wheel end and a plastic knob on the grinding wheel end. Both seem adequate.
Ken
Quote from: thats sharp on January 21, 2016, 05:46:05 PM
As per the Tormek instruction book I always replace my sg-250 wheel when the stone gets to about 200mm. Over the years I have accumulated a lot of stones in this category.
Occasionally, I will fit one on my Tormek to sharpen a large cleaver or double axe. Other than that I have not found any other suitable use for them. Considering the cost of these wheels I was hoping to hear some ideas of how to use them beyond the Tormek recommended wheel life. Thanks for your input.
I use wheels down to a smaller diameter. If you have a lot of 200mm wheels I would but them from you!
Let me know.
One of my favorite quotes is by Mark Twain, "Man is the only animal with the one true religion, all seven of them."
The handbook also talks about replacing the stone when it reaches 180mm. I believe the real problem is keeping the stone wet. I would recommend replacing the grinding wheel while it still has useful life and reserving the worn stone for work which is less critical.
Ken
I have noticed worn Tormek grinding wheels listed on ebay. Most are under eight inches (200mm). The latest price is $35 US. I think the most practical use of worn grinding wheels, if not as table weights, is to sell them and put the proceeds toward a new wheel.
Ken
I currently have the T-7 and am looking at purchasing a T-4. I am very interested in using my used up T-7 wheels on the T-4 so I would like to ask the knowledgeable folks on this forum the following question. What would be the best way to reduce the width of a used T-7 stone to fit the T-4 shaft? Is it doable?
I would guess that someone would be able to suggest a method to at least make this remotely possible. Ideas?
The wheel dressing tool would/should work but that sounds like an exercise in futility to me. How you would maintain the depth of cut evenly across the diameter of the wheel is unknown. Plus, if the diameter is too small for use on the T7, it is not going to be any larger when placed on the T4.
Quote from: thats sharp on April 18, 2016, 03:36:37 AM
I currently have the T-7 and am looking at purchasing a T-4. I am very interested in using my used up T-7 wheels on the T-4 so I would like to ask the knowledgeable folks on this forum the following question. What would be the best way to reduce the width of a used T-7 stone to fit the T-4 shaft? Is it doable?
I would guess that someone would be able to suggest a method to at least make this remotely possible. Ideas?
I asked that very question a while ago, even proposing a "T47" for this. In the end, the general opinion is that it is cheaper to have separate stones & upgrade my T2000's shaft to accommodate easier wheel changing via the knurled screw.
It is possible to convert the T4 to accept the thicker SG-250 grinding wheels. It is also possible to have your worn grinding wheels ground down to 40mm thickness to fit the T4.
You would need to have a custom made made shaft. A local machine shop would be able to make one for you. Bring the shafts to the shop and explain that you want a shaft itentical to the T4 shaft, except being able to handle a 200mm thickness grinding wheel.
You may be able to jury rig your present 2000 water trough for the "T47" and order a replacement for the 2000.
The constraint is cost. I have no idea what the new shaft would cost. I would guess as much as a T4.
If you decide to thin the wheels instead, you would have to romove ten millimeters of thickness. Having flattened a dished oilstone, I can tell you this would be a Herculean task. My oilstone took more than four hours and wore out a two hundred dollar diamond flattening plate. I should have just used the fine side and abandoned the coarse side.
If you can't use the worn stones anymore, use them as weights, shop decorations or sell them cheap on ebay. For about the cost of just the T4 you can buy two new grinding wheels, even the SB-250, which may last longer.
I encourage you to keep thinking creatively, but to consider used grinding wheels like worn out brake shoes.
Ken
Ken
It sounds like your trying to make a Monty Python skit:
Mr, Machinist sir, I would like you to give me the shaft. :D
viva Monty Python!
Ken