Need 8" Buffer Recommendation

[darita]

I want to use Vadim's method of using an 8" buffer for paper wheels.  Right now I'm using a Delta variable speed grinder that has a lot of runout and I don't know what speed the wheels are turning at.  I'm looking for good, reasonably priced, buffer recommendations.

[Ken S]

Darita,

Ascertaining the speed of a variable speed grinder or buffer is easy enough to do. Digital read out tachometers are inexpensive and readily available. I used one when I converted my belt grinders to variable speed. (From practical experience, angle the light slightly. I had problems with straight on reflection.)

An unusual suggestion: Buy a second hand or stripped down T4. (Although there is no official ."T4 Custom", some dealers may sell them that way. Advanced Machinery is one.) The T4 motor spins at 120 RPM, compared with the 100 RPM motor of the T8. Also, for use with a paper or felt wheel, with the water trough removed, the T4 works with a 250mm wheel.

With paper wheels, the need for high speed is to generate enough heat to melt the wax. As I recall, Vadim used no wax.

Ken

[darita]

Darita,

Ascertaining the speed of a variable speed grinder or buffer is easy enough to do. Digital read out tachometers are inexpensive and readily available. I used one when I converted my belt grinders to variable speed. (From practical experience, angle the light slightly. I had problems with straight on reflection.)

An unusual suggestion: Buy a second hand or stripped down T4. (Although there is no official ."T4 Custom", some dealers may sell them that way. Advanced Machinery is one.) The T4 motor spins at 120 RPM, compared with the 100 RPM motor of the T8. Also, for use with a paper or felt wheel, with the water trough removed, the T4 works with a 250mm wheel.

With paper wheels, the need for high speed is to generate enough heat to melt the wax. As I recall, Vadim used no wax.

Ken

That's interesting, as I have a SuperGrind that is doing nothing right now.  Question is, what effect would the slower speed have on the process?  I would think Vadim could have used his paper wheels on a T8, however he chose to use slow speed polishers instead.  Any idea why?

[cbwx34]

I want to use Vadim's method of using an 8" buffer for paper wheels.  Right now I'm using a Delta variable speed grinder that has a lot of runout and I don't know what speed the wheels are turning at.  I'm looking for good, reasonably priced, buffer recommendations.

Your Delta should work.  Most variable speeds run between 2000-3400 rpm.  The actual speed is not that important.  Paper wheels are pretty easy to true to a machine.  (Depends on how much runout there actually is I suppose.) 

I tried paper wheels on a Tormek... works OK I guess, but no advantage I saw over the leather wheel, and doesn't give the same results as running on a faster machine.

Wax has nothing to do with honing... it's only used on the grinding wheel.

[darita]

I want to use Vadim's method of using an 8" buffer for paper wheels.  Right now I'm using a Delta variable speed grinder that has a lot of runout and I don't know what speed the wheels are turning at.  I'm looking for good, reasonably priced, buffer recommendations.

Your Delta should work.  Most variable speeds run between 2000-3400 rpm.  The actual speed is not that important.  Paper wheels are pretty easy to true to a machine.  (Depends on how much runout there actually is I suppose.) 

I tried paper wheels on a Tormek... works OK I guess, but no advantage I saw over the leather wheel, and doesn't give the same results as running on a faster machine.

Wax has nothing to do with honing... it's only used on the grinding wheel.

Believe me, I tried to get those wheels to run true, but no matter what I did, they chisels were bouncing like crazy.  That grinder just doesn't cut it.

[Sir Amwell]

I'm pretty sure Vadim recommended an RPM of 1400 for paper wheels.

[Drilon]

The buffer Vadim (RIP) uses in his YouTube video "Our new setup for Commercial Sharpening - 22 knives per hour" is a Bernardo DS200S with 2850 rpm.

[HaioPaio]

I agree. See attachedYou cannot view this attachment.

[darita]

Is this saying that one should get better results on rock hard felt?

[Ken S]

With your Delta grinder, is your shaft true? Does your original grinding wheel run true? Or, is the fit of the buffing wheel sloppy? A local machine shop can diagnose your problem quickly, probably at little cost. If it can be repaired, it is probably your lowest cost option.

Ken

[HaioPaio]

Here is the link to the full document.
The conclusion prefers half speed grinders over full speed.

http://knifegrinders.com.au/SET/Effect_of_felt_and_paper_wheel_on_edge_retention.pdf

[Ken S]

After reading the full article, I am left with the impression that the half speed buffer/grinder results are slightly better than the full speed results. However, the test results also indicate that these choices are the second and third place finishers. The top marks appear to go to the 90 RPM Tormek.

I can see how investing in a higher speed buffer/grinder would be cost efficient for a sharpener with a contract to sharpen for a large meat packing company. However, how many of us actually do industrial high volume sharpening?
That seems a large iffy maybe for most of us.

I think a more practical solution would be to use the leather honing wheel with PA-70. Put the PA-70 on the leather wheel before grinding to allow it to dry for better friction. These knives are not super steel. Honing can be done either freehand or in a jig. If in a jig, a second preset usb and,if you wish a FVB can be used.

It is unfortunate that Vadim's tragic premature passing prevented him from continuing to evolve his ideas. I believe he had much more future unrealized innovations.

Ken

[cbwx34]

After reading the full article, I am left with the impression that the half speed buffer/grinder results are slightly better than the full speed results. However, the test results also indicate that these choices are the second and third place finishers. The top marks appear to go to the 90 RPM Tormek.
...

I think for felt... but not for paper wheels...

PAPER WHEEL
Deburring on solid paper wheel at high RPM is not recommended.
Deburring on slotted paper wheel at 2850 RPM is conditionally acceptable, provided that that the
contact of the edge with the wheel is less than 1 second per pass, sides are alternated with each
pass, and number of passes is limited to 2 in one go.
Deburring on slotted paper wheel at 1425 RPM is recommended

(Not that I agree or disagree, just quoting the study.)

[darita]

Am I seeing that not only can you run slotted paper wheels on the Tormek, but that they produce a better edge than 1/2 speed grinder/polisher? 

[Sir Amwell]

Thanks CB, as I said earlier Wootz recommended 1400 RPM for paper wheels.
Darita, this is the point. I don't think running a paper wheel on Tormek would be very effective at all. They need those higher but not too high revs to work.