[Azalin]

Or this

[Azalin]

I need recommendation about heat treatment. Anyone knows the raw hardness of 2080 steel? I've used this steel for the main shaft and I can't decide whether hardening is necessary or not. If it is then what hardness should I expect?

Thanks in advance.

[ebrewste]

Here is the spec on the steel:
Chemical composition, Mechanical, physical and environmental properties of ASP 2080,Steel Grades,Tool Steel,

It shows 235 HB for annealed condition, which is ~22 rockwell c
Steel Hardness Conversion Table

That's not very hard. I found a mention of spindle nose hardness of ~60 RC.
Manufacturing Specifications | Parlec Inc.
"The case hardness is designed to give maximum wear life without compromising the RC 60-62 spindle. "

[mactec54]

Or this

This one yes, the first one no

[Azalin]

@macted54
OK, I'll cut the labyrinth that way.

@ebrewste
Thanks for your help.

Main shaft is almost ready for hardening. I just need to cut the slot for the labyrinth seal.
The thread for the lock nut has been cut too. It is M45x1.5. I'll cut the lock nut this week.
I've left .5mm material for grinding on the shaft.

I've talked with two heat treatment shop for this part. They don't recommend the same way to achieve 60-62 HRC. One says vacuum however this method wont harden the steel enough (I guess), other says quenching to salt will harden it to what I want but the steel will/can be deformed.

The other way is nitriding I guess. What do you recommend?

[mactec54]

Main shaft is almost ready for hardening. I just need to cut the slot for the labyrinth seal.
The thread for the lock nut has been cut too. It is M45x1.5. I'll cut the lock nut this week.
I've left .5mm material for grinding on the shaft.

I've talked with two heat treatment shop for this part. They don't recommend the same way to achieve 60-62 HRC. One says vacuum however this method wont harden the steel enough (I guess), other says quenching to salt will harden it to what I want but the steel will/can be deformed.

The other way is nitriding I guess. What do you recommend?

Nitriding is very thin so is usually done after grinding, with a very light touch up after, it has been nitrided

You have some conflicting information, Vacuum heat treatment only means your workpiece is heated in a Vacuum, this prevents, scale forming on your part,( Which you don't want on something like this ) it would or could be still quenched, in whatever is needed for your shaft, that is why air hardening steel can be better sometimes for parts like this

So a Vacuum furnace is always the best to use if it is available, ( this is how your part is heated up to it's quench temperature ) the hardening process is no different after it has been heated

Is your material a case hardening material or a through hardening material, case hardening material is the normal for spindles and shafts like this, and can be quite normal to nitride, your spindle after heat treatment & grinding

[Azalin]

OK here's my labyrinth design. Thanks Mactec

[Azalin]

OK I left the spindle to a heat treatment shop. This one is different than the two I've mentioned earlier. The guy said that he could get 60'ish hardness on 2080 steel. I'll see.

The shop is very big with, complete with a few sections. One section was very scary (looked very bad), They don't allow people to get there. My first time in such shop. Anyways, I'll get the spindle back in two days.

[Azalin]

I just took the spindle from the shop. 59HRC hardness which is not bad I guess.

[Azalin]

The Dremel is too weak to grind hardened steel and the wheel is too small. Dremel smoked eventually and I stopped it but it is still working. Now I need to make a small grinding attachment for my lathe. Actually 2 grinders. Both for internal and external.

[John1987]

Are you sure you want to do it by yourself? May be the best way is to find real OD/ID grinder?

[Azalin]

I'm going to sell my lathe so better not to buy anything for it.

[ebrewste]

The Dremel is too weak to grind hardened steel and the wheel is too small. Dremel smoked eventually and I stopped it but it is still working.

Don't forget how critical proper grinding wheels are. The junk grinding wheels that come with a Dremel are just not made to grind a job like that. Your Dremel might be able to do the job faster than you can make a new grinder if it had proper grinding wheels. Of course, a Dremel is still the wrong tool for the job, but it is a different problem than the grinding wheel problem.

I've ground carbide in my lathe with a diamond wheel to 0.0002" (I was surprised, too) with a Dremel. It is possible...

Edit:
I dug up the picture of grinding the end mill. I doesn't fit your case very well, but it sure shows the importance of using the right wheel, even if your grinding setup is crazy.

http://i46.tinypic.com/29nceme.jpg

[Azalin]

Thanks ebrewste. As you say the Dremel may work however mine is about to puff so better not use it on the lathe anymore

I am working on a small grinding attachment these days. It's not finished yet. As you see in the pics I used 4 bearings on the wheel side and 1 on the pulley side (may add another one). The wheel is 50mm dia and 13mm width. I'll use my old tool post as housing. The 20mm diameter cylinder is a perfect fit. I'll put a 12-15v BLDC motor to the opposite but I need to cut a mount for the motor first. I don't know the name of material the woodish pulley I made. I used to use that to make pulleys for my former mill. Anyway, I'll use 5mm o-ring between pulleys.

I know this is not a real grinder but it is better than not having a grinder.

[Azalin]

My Nachi 7009 AC bearings arrived. Nice and shiny.

[zamazz]

That pulley looks to be phenolic. Where'd you source your grinding wheels? I'm looking to build something similar.

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[Azalin]

Search for "Proxxon grinding wheels". Nice German made items.

I've ordered a new but stronger motor for the grinder because the one I have appears to be very weak. I'll also replace the o-ring with a V-belt for long term use.

[Azalin]

That pulley looks to be phenolic.

ah yes. Exactly.

Attachment 307006

[Azalin]

[Azalin]

The baby grinder did a good job.

https://youtu.be/Nui_30N5pVo

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