AWGB Woodturning Forum
General Category => General Discussion => Topic started by: Drewcole on September 09, 2020, 11:13:48 AM
-
Hi guys,
1st time poster and fairly new to turning so sorry if I've missed any protocol.
I'm having some issues with my RP250 lathe regarding vibration, it's fine turning pens and running without any load. But recently when I try to turn a bowl anything bigger than say 6in I'm getting terrible movement to the point where the lathe is moving across the worktop.
I've adjusted the feet, tightened any bolts/screws I can find and changed the belt (was pretty worn). My next step is the bearings I think, but I just wanted to see if there is anything missing something silly? I've also bolted it to the work top but is still vibrating so much that it wouldn't be safe.
Any help would be amazing!
Drew
-
First thought would be what speed are you set to?
Second would be how well balanced is the work piece, even 450rpm is quite fast if the load is unbalanced. bigger lathe bigger bits of timber but if I am turning a 10" say 1" off centre I have the luxury of starting a 0rpm and turning it up gradually have turned off balance pieces at around 250rpm despite my lathe weighing about 10x yours.
I suggest you get a balanced piece 4" to 6" in the lathe at 450rpm with the lathe turned off spin the wood by hand and mark the top a few times, if it is balanced then the marks should be random as there will be no heavy part pulling to the bottom.
Give that a try see if the results are any better.
ALL lathe manufacturers overstate what a lathe is capable of, the DML250 says it can do a 10" bowl, but that will be in ideal timber perfectly mounted, mine says it can do 68" but I would probably want to be outside the workshop when it started spinning that!
-
Hi, thanks for the reply.
I'm starting of speed wise on its lowest setting which is around the 500 mark and getting it to decent shape, in the past I'd jump that up step by step till I'm turning at 1500. Is that to fast for bowl work? I'm kinda working from YouTube vids so I'm a complete beginner.
I'll try again at a lower speed to remove more mass and follow the advice you gave above.
I think I'm trying to run before I can walk with it all. I've just got the bug now.
Thanks drew
-
My first comment would be ...don't believe a lot of what you see or hear on Youtube! Some of it is good , of course, but you need to know the difference. Go to an AWGB approved tutor - it will prove very cost effective in the long run and you stand a chance of keeping your body parts in one piece.
Secondly, don't be in a rush to get your bowl turned. It can take even an experienced turner a (comparitively) long time to get a blank into a balanced state so that it can be turned at any faster speed. 450 rpm is more than plenty for an unbalanced piece, it just takes a bit longer.
Good luck - and keep practising your cuts!
-
Thanks for the advice and encouragement!
Is there a list of tutors somewhere or is it just a case of asking on the forum.
-
Also, try the RPT website for lists of woodturners offering tuition. https://www.registerofprofessionalturners.co.uk/find-a-turner/
ATB John
-
Looks like your issue is a out of balance blank, this is difficult to overcome with fixed speed belt change lathe's
If you had a variable speed lathe you could turn the speed right down to very slow and as it comes into balance increase the speed
-
Start here:-
https://www.awgb.co.uk/training/ (https://www.awgb.co.uk/training/)
On YouTube, first thing is look at the size of the lathe they are working on, if it is a lot bigger than yours then they will be able to turn bigger faster more out of balance, do not try to match what they are doing!
Other things are RPT (Register of Professional Turners) doesn't signify they are a good teacher, just that they earn most of their living from turning related sources, but it is a clue!
There are things that are done by many good turners that have a combination of sound / feel / experience that in combination makes the difference between safe and dangerous YouTube doesn't always convey that border.
I would say join a club, obviously that is a problem at the moment however your local AWGB club will probably be able to link you up with online meetings, and maybe one to one meetings with social distancing measures reach out and ask what is available in your area.
https://www.awgb.co.uk/clubs/ (https://www.awgb.co.uk/clubs/)
-
Thanks for all the advice guys, much appreciated.
-
Looks like your issue is a out of balance blank, this is difficult to overcome with fixed speed belt change lathe's
If you had a variable speed lathe you could turn the speed right down to very slow and as it comes into balance increase the speed
I learned on belt driven lathes, now I have learned more I would say that variable speed lathes are the only ones I would recommend, so much safer, for the beginner it is great to be able to start slow (0 rpm on mine) and find the right speed, for the experienced the safety is half of it the convenience the other half. unfortunately many new turners start on a tight budget and buy fixed speed change lathes.
In answer to my first post you intimated you turn bowls at 1500, I almost never turn bowls over 1000rpm if I go over it is for a specific cut when I am able to take the speed up carefully.
-
OK that's interesting, I think I've always been turning at 1500 once the bowl was stable. Might explain some of the issues I've been having when finishing.
Thanks for all the info, should of come hereto begin with.
-
Let us know where you are Drew, there may be someone on here close to you that can offer help and advice. Julian
-
I'm in Newcastle but can travel
-
Drew, check out Andrew Hall, as he's up the road from you in Durham
-
Thanks guys, appreciate all the help.
-
Twisted Trees https://www.awgb.co.uk/training/ going to this link does not signify that any of the tutors on that page are any good either.
-
Twisted Trees https://www.awgb.co.uk/training/ going to this link does not signify that any of the tutors on that page are any good either.
;) Very true John, but a specific link to training resources may differentiate between teachers and makers. For instance I am very capable of doing all of the mathematics that people up to the age of 18 need to know, but I couldn't be a maths teacher because I don't have the communication skills to handle teenagers. :)
I also felt it politically incorrect to direct from the AWGB Forum to the RPT website, but OK to say trust the RPT badge if seen on YouTube
-
Twisted Trees https://www.awgb.co.uk/training/ going to this link does not signify that any of the tutors on that page are any good either.
I would disagree with the above statement - the page linked lists all the AWGB training courses. We aren't likely to employ a tutor for those unless they are competent...
-
Twisted Trees https://www.awgb.co.uk/training/ going to this link does not signify that any of the tutors on that page are any good either.
I would disagree with the above statement - the page linked lists all the AWGB training courses. We aren't likely to employ a tutor for those unless they are competent...
The lst of tutors includes anyoine who offers their services as a tutor. THey don't necessarily have to go through any training course. I anm on it and haven't done the AWGB course. I have teaching qualifications and am a member of the RPT but none of that is mentioned so is unknown to anyone investigating their locality for a tiutor.
Pete
-
Pete,
I think you missed the point, the page referenced does not have a list of tutors...