Lap Sharp sharpening tips and media

[Frank Martin]

I recently acquired a Lap Sharp and seems like great sharpening tool. However, I need to purchase discs that are used as the sharpening media. These are 8" in diameter. Most of what I need to sharpen are Veritas PM-V11 and A2 steel plane irons and chisels.

I am looking for suggestions from other Lap Sharp users on the discs and other tips to get the most out of this system. There seems to be very little information on it.

[Jim Koepke]

Not sure if these are compatible:

http://www.leevalley.com/us/wood/page.aspx?p=48435&cat=1,43072

They are 8". The bolt that mounts the disk is a 1/4".

I have multiple platters for quick changing.

jtk

[Andrew Pitonyak]

If my memory serves me correctly, the Lap-Sharp has a square hole in the center.

When I was testing a WorkSharp, I purchased round discs of the appropriate size and then used another disk as a template to poke the hole that I needed. That was long enough ago that I do not remember the details, but, they were much cheaper than the WorkSharp branded material. I assume that you could do the same for these, it is just a bit more difficult to cut the square hole. It is probably worth it to test with a disk or two to see.

I assume that the biggest driver is related to the condition of the blades and the type of sharpening that you will do. If you are not removing significant material, then you probably need mostly finer abrasives. Do you do any part by hand? Adding a secondary-bevel?

I assume that much of the advice for the WorkSharp would also apply to the Lap-Sharp (see http://www.sawmillcreek.org/showthread.php?219929-Work-Sharp-3000-diamond-discs-establishing-chisel-surfaces)

[Joe Beaulieu]

I have a Lap Sharp myself and I basically have gone back to stones. It's a great system, but the cost of the abrasives is just too high. I like restoring old planes. A lot of the time I have to grind a new bevel etc. They (Lapsharp - Wood Artistry) want $25 for a single sheet of their heaviest and second heaviest abrasives. Don Naples is a really nice guy, and he is really responsive when things aren't right, but the abrasives are just way too expensive.

Frank - if you find anything to extend the usefulness of that unit please let me know. I really like the concept. The system works, it's just way too costly. I bought the new honing guide because they were coming out with a new line of abrasives. Their argument is that the new diamond coated abrasive lasts much longer, but I am not seeing that to be the case. And at $25 per sheet it is way beyond affordable. I just keep my stones ready to go and they do the trick.

Joe

[Andrew Pitonyak]

Joe, did you try to adapt abrasives not specific to this unit? 8" discs are available, I just don't know if the backing types are correct.

[Frank Martin]

It is a good idea to try the abrasives for the Veritas sharpener. I actually have the Veritas system too and will decide which one I keep. I should order some of those discs from Veritas as I don't have many of the grits. The reason I wanted to try Lap Sharp is the slower speed and ability to use water & detergent lubrication that makes lapping backs of blades possible, which I never had good luck with Veritas.

Regarding cost of discs, I have not checked Lap Sharp diamond, but $25 a disc not sure I would. For major grinding, I use a 1"x42" belt sander. I found in the past the Veritas system takes a long time to accomplish major steel removal, of course cost more money with the discs too. I plan to continue using the belt sander for major removal and only use the Lap Sharp for sharpening/honing.

If anyone knows a better / cheaper source for 8" discs than Lee Valley, please share.

[Jim Koepke]

I have the Veritas® Mk.II Power Sharpening System. A slower speed would be helpful at times.

My Veritas system isn't used much these days for major metal removal. For me that seems to work better on a 4' granite slab with pressure backed abrasive papers.


If anyone knows a better / cheaper source for 8" discs than Lee Valley, please share.

I do not know the configuration of your discs. Here are a couple of links to abrasive dealers:

http://www.supergrit.com/

I have purchased roll stock from them.

http://www.industrialabrasives.com/

Not sure that I have ever purchased from them. They have an 800 number.

jtk

[jamie shard]

A slower speed would be helpful at times.

Probably a silly question... Could you run it on a power cord with a dimmer switch? I'm genuinely curious.

[Andrew Pitonyak]

Probably a silly question... Could you run it on a power cord with a dimmer switch? I'm genuinely curious.

NO..... NO..... NO...... It is a trap.

First,light dimmers are designed to drive resistive loads and motors usually have an inductive load. So, you should first figure out what kind of load you have.

Motors in corded power tools are usually resistive. I do not know about this device.

Now, perhaps someone who knows more than I (I don't consider myself sufficiently informed, just enough to be afraid to do it).

[Jim Koepke]

NO..... NO..... NO...... It is a trap.

Good answer.

Some AC motors can be speed controlled. Most do not respond well to such attempts.

AC motors that can be speed controlled are usually 3 phase or have other design features.

Here is more information:

http://www.orientalmotor.com/technology/articles/article166-1e.html

jtk

[Joe Beaulieu]

Joe, did you try to adapt abrasives not specific to this unit? 8" discs are available, I just don't know if the backing types are correct.

No Andrew - I did not. I was not aware of any that would work. Now that I am I will give them a try. I would love to be able to rely on that system a bit more. I'll let you know how I make out!

Joe

[Joe Beaulieu]

A dimmer is most assuredly a bad idea. However you can find something called a Variac - Variable AC is the idea I believe. My understanding is that a Variac will not cause the induction issues that a dimmer most assuredly would.

Does the Veritas machine run faster or slower than the Lap Sharp? The Lap Sharp runs relatively slowly. I can't imagine wanting to get slower than the lap sharp. Not at home, don't have the spec available. I will try and remember when I get home to post the rpm.

[Frank Martin]

Does the Veritas machine run faster or slower than the Lap Sharp? The Lap Sharp runs relatively slowly. I can't imagine wanting to get slower than the lap sharp. Not at home, don't have the spec available. I will try and remember when I get home to post the rpm.

Veritas runs at 650 rpm vs. Lap Sharp at 200 rpm. So, Lap Sharp is better for polishing backs.

[Trevor Goodwin]

A dimmer is most assuredly a bad idea. However you can find something called a Variac - Variable AC is the idea I believe. My understanding is that a Variac will not cause the induction issues that a dimmer most assuredly would.

Does the Veritas machine run faster or slower than the Lap Sharp? The Lap Sharp runs relatively slowly. I can't imagine wanting to get slower than the lap sharp. Not at home, don't have the spec available. I will try and remember when I get home to post the rpm.

The machine is most likely running an induction motor, so the speed is a function of power frequency and number of poles in the motor. A variac changes voltage, not frequency, so it will try to run at the same speed albeit with less available power for sharpening. What you'd need is a Variable Frequency Drive (VFD) but these are expensive and not all induction motors are designed for variable frequency.

[Karl Andersson]

For what it's worth, several years ago I emailed Lee Valley explaining that my Veritas Mark II system was great, but it was too fast for small carving tools (touch a thin, small blade to the finest grit for about a second and it instantly turns a beautiful blue). I asked if a motor controller could be used to slow the RPMs down. In probably one of Lee Valley's least customer-friendly moments, I got an email back from "an engineer" about 2 weeks later who basically said "no, you can't slow the RPMs with a motor controller" and furthermore "I don't know why you'd want to do that". Must have exceeded his 3-sentence reading capacity.

I have found that keeping smaller, lighter tools closer to the center spindle does help avoid burning, due to the lesser circumference. I think the 650 RPM speed is OK for plane blades and thick bench chisels, but it would be much more useful a tool if it could be slowed down for finer work. Old record players used a variety of simple means to provide variable speeds to the platters - drive wheels with different diameters, belt drives with variable idler pulleys, etc.; some days I fantasize about doing some major surgery to the Mark II and adding at least one slow speed...generally after I tire of re-shaping a carving tool with oil stones and try once more to very lightly just touch the tool to the Mark II, just for a moment, and...blued again, dammit.

Karl

[Frank Martin]

It was the too high speed of Veritas that made me buy the Lap Sharp. If you do the backs of blades some other way, Veritas has some better engineered features compare to Lap Sharp. That is the reason I still keep it while trying to decide between the two.

If Lee Valley changed the design to slow down the Veritas speed, it would be my choice.

[Jim Koepke]

generally after I tire of re-shaping a carving tool with oil stones and try once more to very lightly just touch the tool to the Mark II, just for a moment, and...blued again, dammit.

I have blued my share of tools on the MK II power sharpening system.

One thing I have learned is to dip the tool into water before hitting the platter. The water helps to keep the temp down as it boils away. It doesn't give much more time on the platter, but it gives a good visual indicator of the tool heating before you get the color indicators we all despise.

Another part of the learning is the finer grits may do more to cause heat than to remove metal. My smaller tools are not worked on the coarsest grit. They also do not get the finest grit. They are usually worked on the second or third grit (220-500?) and finished using oilstones and a strop.

Also as someone else suggested, keeping toward the center of the disk effectively is the same as slowing the rotation. Just be careful not to run into the mounting bolt. DAMHIKT!

jtk

[Mike Henderson]

It was the too high speed of Veritas that made me buy the Lap Sharp. If you do the backs of blades some other way, Veritas has some better engineered features compare to Lap Sharp. That is the reason I still keep it while trying to decide between the two.

If Lee Valley changed the design to slow down the Veritas speed, it would be my choice.
If the Veritas has a universal motor - instead of an induction motor - you can put a simple router speed control on it. Ask LV what kind of motor is in their product.

Mike

[Frank Martin]

If the Veritas has a universal motor - instead of an induction motor - you can put a simple router speed control on it. Ask LV what kind of motor is in their product.

Mike

Mike, there are some posts on this above and does not look like there is an easy way to slow it down.

By the way, I never had bluing issues with the MKII.

[Trevor Goodwin]

The Veritas is most certainly using an induction motor, I can tell this based on its size, weight, and sound. There's a chance it uses a DC motor but they'd probably slap on a speed controller if this were the case. If it were a uni motor it would sound more like a corded drill.

I suspect it uses a belt and pulley to get the speed to 650. I did the numbers a few weeks ago on what sized pulleys you'd need for a 4 pole to make a slow speed disc sander. I found out that to stay above the minimum bend radius for v-belts, one of the pulleys ends up being kind of massive. My guess is that this pulley sits below the platen and is the largest that would fit.

[Mike Henderson]

The Veritas is most certainly using an induction motor, I can tell this based on its size, weight, and sound. There's a chance it uses a DC motor but they'd probably slap on a speed controller if this were the case. If it were a uni motor it would sound more like a corded drill.

I suspect it uses a belt and pulley to get the speed to 650. I did the numbers a few weeks ago on what sized pulleys you'd need for a 4 pole to make a slow speed disc sander. I found out that to stay above the minimum bend radius for v-belts, one of the pulleys ends up being kind of massive. My guess is that this pulley sits below the platen and is the largest that would fit.
If it's an induction motor it wouldn't take much to get it to 650 RPM. Most of the induction motors we use are two pole motors and run about 3450 RPM fully loaded. A few motors we use are 4 pole motors and run at 1725 RPM. But you can get motors with more poles and slower RPMs. For example, a 6 pole motor would run about 1150 RPM and an 8 pole motor about 863 RPM. It would be very easy (not a lot of difference in the pulley sizes) to take an 863 RPM motor to 650.

[Here's (http://www.engineeringtoolbox.com/synchronous-motor-frequency-speed-d_649.html) some discussion on motor speeds verses poles. It's for synchronous motors and Induction motors slip so their RPM is a bit less. For example, a synchronous 2 pole motor on 60 Hz would run 3600 RPM but a regular induction motor is rated at 3450 RPM.]

The motor is probably not a capacitor start motor with a centrifugal switch so you can probably use a VFD on it if you wish. It could be a small VFD. If you choose a VFD with 3 phase output, you need to multiply the VA of the motor by square root of 3 for the size of the VFD. But in small motors like that, you can purchase a single phase output VFD.

But make sure it's an induction motor before you buy a VFD. If it's a universal motor you can easily control it with a router control device. And a router control device will not work for an induction motor.

Mike

[If there's room, you might be able to change one of the pulleys to make it run slower.]