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12th Jul 2020, 05:21 PM #46Golden Member
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- Sep 2009
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Rockwell Bandsaw Identification, Help and Conversion
Went to a local fab shop during the week and bought some 32mm round and 10mm plate. The intention is to push ahead with the reduction drive parts so I can finally get this bandsaw working. I have a real need for it, so want to get it up and running, but loads of other projects keep popping up and taking priority.
The problems with making all these parts is:
1. They take quite a bit of time
2. Some of them are 5” which fits in my lathe but the flat belts keep slipping and so I really need to upgrade the lathe to a belts (Hercus C), so I have to chat to Mal about what’s involved.
3. Cutting plate is a pig. I only have an angle grinder which works, but a plasma cutter would make it much less of a chore.
First up I turned the bush. It’s a stepped arrangement so the larger step will take the plate to mount the larger sprocket to. The smaller step will have a 10t sprocket welded straight to the bush. To mount the larger sprocket I need a carrier. So I cut one out of plate and then had to make it round on the lathe. Interrupted cut and I only had threaded rod to attach it to the chuck. Didn’t work well but was able to slowly take cuts and get it round.
Next up I put it on the bush and welded the rear section. Time for some holes. Got to try out my new DRO and bolt hole function. Wow how easy. Not only drilled mega easy but the fit is exceptional!
Here’s the side that will take the small sprocket. I need to turn this shoulder further in, but that’s a job for next time.
Other side. This will be drilled for a set screw to lock it to the 17mm jack shaft:
The holes lined up perfectly. Have to say the DRO makes a huge difference here. I need to buy some cap headed bolts with a shorter length and nylocks (this was a test fit with what I had on hand):
This smaller sprocket needs to be drilled out to 22mm but I’m not sure how to do that yet. I suspect I’ll need to mount it in the 4 jaw chuck or maybe buy a boring head for the mill.
Then I just need to make 3 more
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13th Jul 2020, 09:07 AM #47Golden Member
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- Sep 2009
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The sprockets are hardened, so boring out the centres to 22mm is going to be a challenge. Anyone have any advice on how to manage?
I was going to give to a mate and have him chuck all 4 in his wood burner and leave them overnight.
Thought was it would anneal them ready for machining, before I try and harden/temper the teeth again.
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23rd Aug 2020, 03:59 PM #48Golden Member
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- Sep 2009
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- Sydney
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I came up with a solution for the sprockets. Had a mate take them home and chuck them in his wood burner overnight. It definitely seemed to anneal them and made boring them much easier. To bore them out I put them in my 4 jaw chuck and eyeballed them straight. 2 jaws on the lower part of the teeth and 2 on the upper. Carbide inserts seemed to go ok but interrupted cut so I went very delicate on the depth of cut.
Unfortunately I didn’t get any pics of the process.
Today I made another sprocket carrier, the one on the jack shaft that has a large sprocket only. Same process as before but much easier now I have gotten rid of the flat belts on my Hercus 9C. I have the opposite problem now which is the cut depth can be so good and I need to keep a good DOC on carbide anyway, that I nearly overshot on 2 parts. Luckily it fit exactly both times
So most of my jackshaft parts are done. This is the motor driven arrangement. The setup on the right is driven by the motor and the sprocket on the left is driven by the small sprocket on the right.
They will be attached to the shaft by a couple of set screws on the backs.
Here is a mock up of how it will all connect:
What’s left?
I need to make another sprocket carrier for the bandsaw, another one for the small sprocket on the end of the jackshaft, plus one for the motor itself. 3 total and it’s mostly done.
The big sprockets are bolted together, so an easy replacement. However to get the right reduction ratio I’ve had to use 10T sprockets as the smaller ones and so these will have to be welded. I don’t want to weld them unless I can try and re-harden them.
I tried to harden them yesterday but I can’t get them hot enough. Not sure if it’s actually a problem give how little they’ll be run, but I’d prefer to if I can.
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13th Sep 2020, 05:55 PM #49Golden Member
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Rockwell Bandsaw Identification, Help and Conversion
In the shed for an hour or two this afternoon and I have the majority of the jackshaft finished. Fingers crossed it fits under the saw as I built it up on the bench, but I’m quietly hopeful.
I was going to put an adjustable slot for one of the shafts but haven’t yet, might see how I go first as the rotation of the chain seem to self tighten a little anyway.
It’s super smooth and works beautifully.
https://youtu.be/VNgfWyCKVZ8
Just need to make another couple of carriers for the sprocket at the rear, one for the rear of the jackshaft and the one for the saw itself.
I had a 10T on the motor but will change it out for a 13T as it didn’t have enough meat for me to be comfortable with the setup. I have the 10T welded to a carrier already but would prefer to have more meat on it and look to slow the motor down instead.
Before anyone says anything. The bolts are temporary. I have 1 set screw in each carrier at the moment but will probably fit 2 on each.
Annoyingly I should have put some registers in the sprocket carriers (large ones) to centre the sprockets. Might still do it so I can get them nice and centred.
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27th Jun 2021, 06:06 PM #50Golden Member
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- Sep 2009
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I’ve gone in a different direction for the motor and bandsaw drive. I was finding the chain just wasn’t working and I’ve decided to go with v belts from the motor and to the bandsaw. I won’t get the exact reduction I need but I have a honking 1.5kw motor so I thought I should get more than enough torque even if I reduce the VFD speed.
A fair bit of machining time to get an old v belt pulley thinned down and bored and drilled to mount where one of the sprockets used to be:
I’ve also done some mods on the motor carrier to drop it down, as I didn’t have enough adjustment.
So now I just need to organise a small pulley for the motor and a big pulley for the saw. Then I need to get a new VFD and I’m ready to test it out.
I’m also wondering if I need to fix the position of the jackshaft or if tension from the motor would be enough to keep It in place?
All in there and ready for the next stage. I think I need to make some simple bushes for the jackshaft pivot, to stop it being able to move on the shaft.
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29th Jul 2021, 01:07 PM #51Golden Member
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The drive is essentially done. Last of my v belts came in today and it’s all working as expected. It’s not running under motor power yet but I’m going to take the VFD off the lathe and wire it up (I have a replacement on the way already).
Here is the motor arrangement:
And the rear:
I was worried about the jackshaft and thought I might have to put a lock on the position but currently the tension between the motor and the top pulley seems to be holding it all perfectly. A small amount of flex in the belts but I won’t know if it will be ok until I run it under power.
All the VFD wiring is in place, just need to wire it up.
Fingers crossed I can get the speed reduction I need for steel. But at the moment I only have a wood blade on it, so I’ll test it with that first.
So next jobs are:
1. Wire up the VFD
2. Test the saw under power and make sure it works ok
3. Adjust all the guides
4. Make a new blade insert.
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29th Jul 2021, 03:15 PM #52Golden Member
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- Sep 2009
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- Sydney
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Rockwell Bandsaw Identification, Help and Conversion
It works!!!
At 30hz I’m getting exactly 60 RPM on the 14” wheels and nearly 100-110 RPM at 60hz. That has me at 220 SFPM, not the 110 I was aiming for but I’ll see if I can get a tougher blade to allow the faster blade speed.
At that speed I ran some plywood through and the motor didn’t even flinch, even at 20hz, so I don’t think I’ll have horsepower problems, just have to be careful with motor heat.
Doing a bit more reading it looks like 220 might still be fine, so I’m really happy with that as I’d prefer to run the motor at 50hz if possible.
Very pleased.
It’s also surprisingly quiet considering the chain drive. And it’s also rock solid, no wobbles or shakes, from 20 through to 80hz.
Trying to find a way to limit the lower end of the potentiometer to 25hz too, can’t find it. I suspect the VFD doesn’t have that option. So I’ve set the VFD to shut off lower than that but I’d prefer to have the potentiometer bottom out at that value. I might add a resistor in.
Now to buy a metal bandsaw blade.
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2nd Aug 2021, 02:14 PM #53Golden Member
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I’ve used it a couple of times already and it’s working great with the wood blade I have. Today I got delivered a Starrett 18TPI bi metal blade and looking forward to giving it a go on some steel.
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2nd Aug 2021, 06:04 PM #54Golden Member
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- Sep 2009
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- Sydney
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Metal blade in and wow it works. Its a slow and steady chewing through plate steel without fuss. I had some initial issues with belt slippage but found the blade guides were too tight, plus I need a slightly shorter belt on the back as I’m at the end of the adjustment.
I was cutting 4mm steel angle and it didn’t have any issues at all. Very pleased.
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