[Ral1121]

How do you tell if your reel has a spin grin or relief grind. Are you able to tell from these pics I took of my McLane. My understanding is if it is a spin grind you cannot backlap but if it is relief you can. My reel has gotten real dull from my scalp and a couple cuts. Wanting to know if I can backlap or not?

 

[Ware]

All reels get a spin grind. The relief gets cut after the spin.

 

[Mightyquinn]

I don't see any relief on the blade so my guess would be a spin grind. On a relief grind you would have a secondary bevel on the cutting edge.

 

[Ware]

Here is a good photo (not mine) of a reel with a relief grind - see the bevel on the trailing edge of the reel blade:

 

[Ral1121]

Since I do not have a relief, backlapping will not help correct?

 

[Ral1121]

When I look at my reel it is closer to the incorrect relief pic than it is the correct relief pic. It does not have a double beveled edge like the pic posted by ware

 

[Ral1121]

Here is a better pic so you can see what I see. I guess the diagram is throwing me off because looking at it I have a relief grind.

 

[Ware]

Since I do not have a relief, backlapping will not help correct?

Seems like I have read that backlapping a reel that does not have a relief cut can cause excessive wear on the bedknife. For a homeowner, that may or may not matter.

 

[Ware]

Here is a better pic so you can see what I see. I guess the diagram is throwing me off because looking at it I have a relief grind.

It does appear that the blades have a relief cut.

I see some pretty good nicks in the first photos you posted. I would backlap it and see what you can get out of it, but if it doesn't hold an edge very long maybe start thinking about getting a fresh grind.

 

[g-man]

Since I do not have a relief, backlapping will not help correct?

Seems like I have read that backlapping a reel that does not have a relief cut can cause excessive wear on the bedknife. For a homeowner, that may or may not matter.

Without a relief cut, the surface area that contacts the bedknife increases over the designed one. This should cause it to wear faster and more force to turn the reel from the extra friction.

If the reel is worn enough that it no longer has a relief cut then the best course of action is to grind a relief (go back to original design). But if you understand the risks (extra engine force needed and faster wear) then a I don't see why you can't backslap.

From a design stand point, all I see (aka opinion) the relief doing is decreasing the surface area at the tip of the blade. It allows the rest of blade to be thicker, stronger, harder to warp/bend. If you look at a swarman, it was designed without a relief.

I would like to learn more about relief cuts from some of our more reel experienced members.

 

[Ware]

I would like to learn more about relief cuts from some of our more reel experienced members.

Toro has a pretty good write-up on backlapping and grinding, starting on page 34 of their Reel Mower Basics document.

Regarding relief, they say:

It is important to understand that Toro reel mowers are designed and manufactured to optimize available power from the engine and hydraulic systems. To help do this, we put a "relief" or back grind on every reel blade to reduce the width of reel blade that contacts the bedknife. This has been proven to reduce power requirements, as well as allow the machine to operate more efficiently. This can be very important, depending on the terrain, type of grass and amount of grass being cut.

 

[g-man]

Thanks for sharing. I read it in the past, but it was good to give it another read. It is interesting that torp says that the relief angle doesn't matter vs jd saying 20 degrees.

On page 40, there is a table with the front angle of the bedknife. It does not list the 1600. Do you know the front angle of your bedknife?

 

[Greendoc]

Since I do not have a relief, backlapping will not help correct?

Seems like I have read that backlapping a reel that does not have a relief cut can cause excessive wear on the bedknife. For a homeowner, that may or may not matter.

Matters a lot. Too much torque required to turn the reel makes chains explode and belts cut. That is after the shaft type parts wear prematurely. Furthermore, that no relief reel must be set with zero contact and that means grass is crushed rather than sheared. That happens. because a homeowner/"landscaper's" reel is nowhere near hard enough to hold a spin grind edge. I have seen zero contact reels with good bedknives and the reel ground down to the spiders. Of course that mower tears up especially Zoysia after the first usage. The golf guys that spin grind do it every week and buy reels every year. But they don't need replacement bedknives very often.

 

[mre_man_76]

@Mightyquinn, have you needed a relief grind yet and if so where do you recommend? I ask because Eastern Turf does it for $135 but they do not use cut a secondary relief only a single relief. He assured me it is indeed a relief grind and not a spin grind.

 

[Mightyquinn]

Mightyquinn, have you needed a relief grind yet and if so where do you recommend? I ask because Eastern Turf does it for $135 but they do not use cut a secondary relief only a single relief. He assured me it is indeed a relief grind and not a spin grind.

I took mine in there earlier this Spring to get the damaged reel ground and asked for a relief grind and they told me that they don't do that so I still had it ground. I wasn't really happy with the results as it looked like they backlapped the crap out of it and the bedknife was worn down to a razors edge. Maybe they have the equipment now to do it correctly. I would give them a shot but just be cautious.

 

[mre_man_76]

Mightyquinn, have you needed a relief grind yet and if so where do you recommend? I ask because Eastern Turf does it for $135 but they do not use cut a secondary relief only a single relief. He assured me it is indeed a relief grind and not a spin grind.

I took mine in there earlier this Spring to get the damaged reel ground and asked for a relief grind and they told me that they don't do that so I still had it ground. I wasn't really happy with the results as it looked like they backlapped the crap out of it and the bedknife was worn down to a razors edge. Maybe they have the equipment now to do it correctly. I would give them a shot but just be cautious.

Airborne!!!
👍🏿👍🏿✌🏿

 

[mre_man_76]

Mightyquinn, have you needed a relief grind yet and if so where do you recommend? I ask because Eastern Turf does it for $135 but they do not use cut a secondary relief only a single relief. He assured me it is indeed a relief grind and not a spin grind.

I took mine in there earlier this Spring to get the damaged reel ground and asked for a relief grind and they told me that they don't do that so I still had it ground. I wasn't really happy with the results as it looked like they backlapped the crap out of it and the bedknife was worn down to a razors edge. Maybe they have the equipment now to do it correctly. I would give them a shot but just be cautious.

Airborne!!!
👍🏿👍🏿👍🏿

 

[dfw_pilot]

TLF is a safe space for both a backlap or a backslap!

 

[mre_man_76]

TLF is a safe space for both a backlap or a backslap!

😂😂😂 well said

 

[TNTurf]

The guy I use only does spin grind. I asked about relief and he just told me he has not seen the need over the 20 plus years he has been maintaining equipment. I can't debate the topic but I can say two months into a spin only, cut every other day, I can cut a single sheet of paper and have only adjusted by one click so far. I have the stuff to backlap but I guess when the time comes I will drop my cutting unit off.