Hollow Grinding Jig

Natlek · Sep 26, 2019

OK guys , I m almost finished with my new 10 inch contact wheel grinder .I have jig for hollow grind BUT it will be to much work to adapt it to all grinders I have .I have make it to work only on my grinder for flat grind .Jig in this video clip is so easy to make .Anyone have one and some word about that jig ?
Jig I have

Working on new one....

Ken H> · Sep 27, 2019

That hollow grinding jig you've got is much like the tool rest I've played with for hollow grinding. Seems to work pretty good. Travis Wuertz (of TW90 fame) has a video where he shows how he does it using a tool rest just like you're showing. Here's a list of video Travis has demo'ing the method.
https://www.youtube.com/results?search_query=Travis+hollow+grinding

Natlek · Oct 1, 2019

Ken H> said:
That hollow grinding jig you've got is much like the tool rest I've played with for hollow grinding. Seems to work pretty good. Travis Wuertz (of TW90 fame) has a video where he shows how he does it using a tool rest just like you're showing. Here's a list of video Travis has demo'ing the method.
https://www.youtube.com/results?search_query=Travis+hollow+grinding

I watched that video from Travis . Good thing is that in his way blade was supported all time on plate .What I don t like in his setup is that I think grinding without water would be little problematic? Where would grinding dust go ? I can see that even with water he has problem with that dust ? My grinder is 6400 FPM and will grind steel fast....If I grind like on first video I post I will loose some support on blade but grinding dust can pass down. .I think that I will try both ways .I finished plate ,it is 3mm thick and about 48HRC hard carbon steel.Too bad ...it is carbon-tungsten steel goes to 68 HRC after quench

I try it on my 17 inch contact wheel ...little strange to grind , I will need some time to learn

Problem I see in booth case is holding blank , say 2.5-3mm blade will not be easy to hold against belt pushing down...Some kind of additional steel with magnet on handle maybe ?

BTW , did you notice that my new grinder have not tension arm ?Tracking wheel is fixed on plate .....for tension I will use tool arm ...pull-lock ....unlock-push . Easy !

Scaniaman · Oct 2, 2019

N Natlek that is interesting, just tightening the belt using the tooling arm.
Keep up the innovating, I like your posts.

Natlek · Oct 2, 2019

Scaniaman said:
N Natlek that is interesting, just tightening the belt using the tooling arm.
Keep up the innovating, I like your posts.

It makes designing grinder a lot easier without tension arm .......and without spring tension/tracking is better .
This is dedicated grinder for this 265mm Dia. wheel .In future maybe I will use it for my rotary platen , IF I don t make another one grinder just for that .Somehow to me it's easier to build from start then to make adoption... motor are cheap

I don t like to change tools on one grinder .It is faster to change belt with arm but HOW faster is it ? 2 seconds ? 5 ? Even CNC machine need some time to change tool

Let see ..............you have grinder with spring .If you want spring to deliver 30 lbs pressure on belt you need to press it to that value and to STAY in that position .Now you change flat platen with contact wheel ....in what position you will set tension arm ? I see in lot of video clip where user don t pay attention to that .EVERY change in pressure will CHANGE tracking and you will need to adjust it on tracking wheel....Never mind , I like it as I make it so only that is matter

Now I need to improve somehow this platen-jig

Natlek · Oct 2, 2019

OK

I burn my shirt , I cut/ruined one new belt ................to learn that grinding on bottom side of plate like Travis do it , won't work without water ...no way !
It build grinding dust right on blade and under flat part of blade ..............fast.I will open plate more so I can try other way and that is that ...........my square tube jig work for sure