Use for Worn Out Grindstones

[jeffs55]

The stone for the T8 is wider, so if you are thinking about using your worn out T8 stones on a T4, it will not fit.

[Elden]

The T4 shaft is slightly shorter than the T7-8 shaft and is made differently as well . This subject has been covered in a previous thread(s). One is:
https://forum.tormek.com/index.php?topic=2834.0

[Herman Trivilino]

Does a SG250 for a T8 that is worn below 200
work like a new stone on a T4

It has the same diameter but it's wider, by 50 mm, I believe. The frame on the T4 is smaller, so it's probably more tolerant.

[Ken S]

When my T4 first arrived, I was not able to have enough time to actually sharpen with it for a while. What I was able to do was set it side by side with my T7 and do some in depth build comparison. I was initially surprised with how many parts were shared. The bolts, nuts and washers which hold the things together are essentially the same parts. The shafts have the same diameter, only the length is slightly different. The T7 uses a 250 mm diameter grinding wheel, hence the SG 250 designation. The T4 uses a 200mm diameter grinding wheel, the SG 200.  The T7 wheel is 50mm thick;the T4 wheel is 40mm thick. They share a common 12 mm bore size. Incidentally, a 250mm wheel is not quite the same as a ten inch wheel, which is why some of competitors' wheels barely fit.

My first CBN wheel is eight inch by one and a half inch or 38mm. This is only slightly thinner than the SG 200. I bought it for the T4. It has a one inch bore diameter and uses a 12mm reducing bushing to fit on the Tormek. It fits nicely with no modification. To my surprise, it also fits on the T7 size Tormek just as well, again with no modification.

It is presently very early in the morning. I would wake the rest of my household if I went down to my shop to verify whether or not the T4 shaft is long enough to hold an SG 250. Even if it did, the water trough is too narrow.

I have used eight inch Norton 3X wheels and my 180 grit eight inch .CBN wheel on the T7 and T8, however, I did this only to see if it was possible. It is posdible, however, this size works more efficiently with the T4. The T4 was dedigned for this size.

The T4 could easily be modified to work with worn SG 250 wheels by a machinist. The modification would not be difficult; it would be expensive and require a custom water trough and probably a custom shaft. Such a customized T4 would cost more than a new T7 or T8, both if which include s new SG 250.

As much as the old Yankee "fix it up, make it do, make it last" is ingrained in me, I can not make sense costwise of trying to use a Tormek grinding wheel beyond its useful life. By all means, as it becomes near that point, reserve it for some work. Use it, like Steve Bottorff does with eight worn out wheels, as a weight to hold down his folding sharpening table in the wind. Use it as a counterweight with line and pulleys or as a door stop.

One of the design pluses with the Tormek is the large grinding wheel. Don't nullify this by using tiny wheels.

Ken

[SharpenADullWitt]

T4 verses T7 water trough.

So they don't have the same mounting points?  You couldn't just use your T7 water trough, with a custom shaft?

Ken, on the brake subject.....

Things to consider.  How is your hearing?  It is one thing if you are deaf, or have hearing difficulties and can't hear your brakes squeak, it is another, if your always blasting the radio, and ignore the sounds your car makes.  Not any different then listening to the grinding when using a Tormek.  Change of pitch, you changed the angle.
What kind of terrain and driving.  Off road, 4x4, can cause more punishment and more use of the brakes, then a hyper-miler.

[Ken S]

SADW,

Thanks for your thoughts. I think my hearing is OK for my age. I am senditive to car noises. ( I was a troubleshooter for thirty five years with Ma Bell.) When I listen to the radio in the car (about half the time), I listen to NPR news and classical mudic. I am not a blarer.

I drive like an old guy, conservatively and mostly on secondary roads.


The T4 and T7 troughs have different mounting points. The T4 trough is smaller. I think the T4's heritage is more for a European market, with more knife work. The T7 US market is primatilt with turners.

Ken