[Azalin]

Some shots for the unfinished taper bush.

I cut the taper for 3 degrees angle. Material is 304 SS.

[Azalin]

The shank is 8mm thick. Should I remove more metal to make it thinner?

[RCaffin]

Um ... I can't see how you are going to pull the taper into the pulley? I have a thread at the narrow end, so it cannot be very thin there.
Cheers
Roger

[Azalin]

Hi Roger,

I decided to make it bolted type. I'll drill some holes to the shank. Similar that can be seen on the image below:

[handlewanker]

Hi.......re-post 341..... as Rog said, with this type design there is a thread at the small end for a nut to pull the bush taper into the pulley bore......the nut has to be on the top side for accesibility when the pulley is on the spindle ....also, you will have to split one side of the bush all the way to allow it to close down on the shaft and the bore as it pulls in, which makes the thread on the end a critical item to cut.

But all is not lost.....you could recover the part by drilling two holes in the flange of the bush, diametrically opposite to one another and drilling and tapping two corresponding holes in the pulley face....this will allow you to use two cap screws (which stay in the pulley) to pull the bush into the taper........you will need to split the bush along it's length first.

You should fit the screws in from the top side and tap the holes in the pulley, making the screws a clearance fit in the flange and tap the pulley holes so that the screws appear on the face of the flange and are uppermost when the pulley is fitted........if you have enough thickness in the flange you should counterbore the holes in the flange to have the screw heads flush with the face.

You will need to drill two more holes in the flange diametrically opposite to one another and at 90 deg to the previous holes.....these need to be tapped.....same thread as the locking bolts...... to act as jacking holes to get the taper bush out of the pulley

This is a similar principle as the Fenner taper lock bush, except it has a flange.....the Fenner taper lock bush is also much bigger in diam as it has the bolts going through it....half in the bush and half in the pulley but without a flange.

edit....your last post got in before I finished mine......that design is going to be difficult to mount ...I think.
Ian.

[RCaffin]

That flange may be a shade narrow.
Perhaps you should go for 4 or 6 smaller hex heads around the rim? Swap bolt size for bolt count.
Cheers
Roger

[Azalin]

Hi again,

@Ian and RCaffin thanks. I agree all.

How does it look?

[Azalin]

I'll drill the holes on my CNC. The 6 red colored holes are for fastening and the 3 blue ones are for removal.

[RCaffin]

That looks rather nice.

Note: You will need to run a thin cut through the taperlock so it can close down and grip. A 0.5 mm slitting saw is nice, although I have also used a thin hacksaw blade! So the bolt holes need to be just a shade larger than the bolts.

Cheers
Roger

[Azalin]

Hi Roger,

I have some nice slitting saw blades but the taper lock is a little hard (304) for the blades I guess. Should I use cutting fluid or just cut dry with low blade RPM?

[RCaffin]

If they are good slitting saw blades, they should handle 304 OK. But actual slitting conditions ... VARIABLE!
Low RPM is probably good: a hacksaw does not move all that fast. Also, a slitting saw has a large diameter compared to a milling cutter, so even low RPM can give a high surface speed.
Cutting fluid is useful, but can cause the chips to collect at the entry and block the saw, leading to trouble. (Spelt broken saws and $$.)
A good mandrel or arbor is needed: you don't want the blade wobbling!
Feed - low, with small chips. Thin saws are not that strong after all.

I have had some success with low RPM and an air blast to clear the chips, with pulsed mist for lubrication. This was with very thin saw blades too.

Cheers
Roger

[handlewanker]

Hi....I second that...all.......but, as it's for a one off, I would just mark it off and cut it by hand with a regular 18 TPI hacksaw blade....and a bit of elbow grease..........5 minute job....the slot width is not important as long as it stays open when the sleeve is tightened.

Setting up for a slitting saw operation will be time consuming and fraught with problems......as I see it.

With the design as it now stands. I would have the flange with the tapped fixing holes at the bottom of the pulley and the bolts in the top face of the pulley, sunk into the pulley face....more room for the heads etc......cap screws of course.

The choice is that you have harder material in the flange to accept the tapped holes when tightening the fixing bolts and a hard face on the inside face of the flange to press against when you want to remove the bush and pulley.
Ian.

[Azalin]

Hi again.

Drilled and tapped. I'll try to cut the taperlock tomorrow.

[Azalin]

I managed to cut the taper. Ruined all my 3 blades though. I think my 2.2kw spindle doesn't have the torque I needed at slow speed so I had to increase the speed. That worned the blades out.

I'll post the pics tonight.

[Azalin]

[RCaffin]

Hi Azalin
If you are running a 2.2 kW 3-phase motor off a VFD, I would imagine that the minimum speed the spindle could run happily at might be up in the thousands of RPM? I have seen systems where the minimum was ~6000 RPM.
I find a couple of hundred RPM is about right on my mill! I would not hesitate to try 120 RPM, or 2 cycles/second. Even that might be a bit fast in some cases.

You got it done. But maybe your next project might be a speed REDUCER for the spindle?

Cheers
Roger

[handlewanker]

Hi....well you got there eventually.......a 100mm diam HSS slitting saw needs to run at 75 rpm max and on 304 probably OK ........a high speed spindle is not the best choice to go down on the rpm due to torque limitations etc.

Once this spindle is in operation things will be a lot different.... milling wise.
Ian.

[RCaffin]

What Ian said. My figure of 200 RPM was for slitting saws in the 35 - 50 mm dia range (or smaller)!

Cheers
Roger

[assink]

Don't forget to oil the surfaces before mounting.
Especially stainless steel seizes fast.
Don't use grease or any other lubricant that has solids in it.
Tensioning the bolts should be done in 180 degree pattern, so force is evenly spread across the bushing.

[Azalin]

Hi,

@Roger, the spindle I used is a 2.2kw water cooled 24k RPM Chinese spindle. I don't think I can modify it to reduce its speed. What I need is a milling machine for such jobs. That's my next project tho.

Don't forget to oil the surfaces before mounting.
Especially stainless steel seizes fast.
Don't use grease or any other lubricant that has solids in it.

Good point. Thanks.