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Viceroy 280 synchro getting hot.
Posted: Tue 02 Jun , 2009 18:22 pm
by Pete.
Hi folks.
I have this lathe and it works very well except for it gets hot when used at high speed. I had cause to use it at high speed for extended time the other day and noticed the following problems. First symptom is the high/low gear lever becomes difficult to move, then as it gets hotter I find that when I shut it off the spindle ran down much more quickly than normal, so it seems that something is getting tight.
Any ideas/comments greatly appreciated.
Pete.
Re: Viceroy 280 synchro getting hot.
Posted: Tue 19 Aug , 2014 9:00 am
by patrick oates
Pete. wrote:Hi folks.
I have this lathe and it works very well except for it gets hot when used at high speed. I had cause to use it at high speed for extended time the other day and noticed the following problems. First symptom is the high/low gear lever becomes difficult to move, then as it gets hotter I find that when I shut it off the spindle ran down much more quickly than normal, so it seems that something is getting tight.
Any ideas/comments greatly appreciated.
Pete.
Re: Viceroy 280 synchro getting hot.
Posted: Wed 20 Aug , 2014 10:53 am
by rpwilson
Don't I recall reading on here somewhere that this a problem with early 280s because the Delrin gears expanded more than expected and caused things to bind up, and that this was cured on later machines by increasing the clearances in the gear teeth?
Richard
Re: Viceroy 280 synchro getting hot.
Posted: Thu 21 Aug , 2014 20:42 pm
by Pete.
rpwilson wrote:Don't I recall reading on here somewhere that this a problem with early 280s because the Delrin gears expanded more than expected and caused things to bind up, and that this was cured on later machines by increasing the clearances in the gear teeth?
Richard
Yes the gear was made with more clearance but Delrin wasn't invented back then. Delrin replacements work well though.
Re: Viceroy 280 synchro getting hot.
Posted: Sat 23 Aug , 2014 12:43 pm
by patrick oates
thank you for these posts this is just as i suspected wheni remove this gear of its spigot mountings it appears to tirn over more freely.thank you again as i do have problems engaging the low ranne.i have passsed silver paper between said gears and it destrys it.i need to take gear out and shave it does abody have headstock drawing.sorry about spelling no glasses
Re: Viceroy 280 synchro getting hot.
Posted: Sun 24 Aug , 2014 2:25 am
by rpwilson
Pete. wrote:rpwilson wrote:Don't I recall reading on here somewhere that this a problem with early 280s because the Delrin gears expanded more than expected and caused things to bind up, and that this was cured on later machines by increasing the clearances in the gear teeth?
Richard
Yes the gear was made with more clearance but Delrin wasn't invented back then. Delrin replacements work well though.
I don't know much about plastics. I've just looked up the drawing and the original material (in 1978) is specified as 'Technyl A90', whatever that might have been.
Richard
Re: Viceroy 280 synchro getting hot.
Posted: Sun 24 Aug , 2014 9:24 am
by Pete.
I don't think you'll find any info on technyl 90 - I couldn't. For a new gear Acetal/Delrin is ideal.
Patrick I would first check the condition of your original gear. It might be chewed up down one side from moving gear changes, in which case a new gear would be the solution.
Re: Viceroy 280 synchro getting hot.
Posted: Fri 29 Aug , 2014 8:50 am
by patrick oates
is it possible to get a new gear and how do i know that new gear will have suffiecnt clearance.you are right the old gear has some damage where effort has been made to engage it but it is obviously heat during running which is causing the the binding.i cant move the centre distance of gear.i have freind with milling equipment and i thought about shaviing a little bit of each tooth
Re: Viceroy 280 synchro getting hot.
Posted: Fri 29 Aug , 2014 10:01 am
by rpwilson
patrick oates wrote:is it possible to get a new gear and how do i know that new gear will have suffiecnt clearance.you are right the old gear has some damage where effort has been made to engage it but it is obviously heat during running which is causing the the binding.i cant move the centre distance of gear.i have freind with milling equipment and i thought about shaviing a little bit of each tooth
There is a drawing BVS 100/105 which I downloaded off this site which shows the layshaft gear and has notes of the amendments. The layshaft gear had its PCD reduced from 5.417" to 5.397", and the OD reduced from 5.583 - 5.579" to 5.563-5.559".
The spindle gear is on BVS 100/108 and had its PCD reduced from 5.667" to 5.647" and its OD reduced from 5.833 -5.829 to 5.813 - 5.809. Basically they reduced everything by 20 thou. There is also a later note which amends the dimension for the width of the layshaft gear from 7/8" to 0.875-0.870"
I suppose if the teeth are OK it should be possible to skim 20 thou off diameter, and recut the teeth 10 thou deeper
These changes appear to have taken effect at the end of 1978, with the tighter tolerance on width coming in at the end of 1979. The gears are 12DP, 20 degrees PA. My lathe is serial No.28658 and appears to incorporate the modifications, at least it doesn't seem to have binding problems. Is yours earlier than this?
Re: Viceroy 280 synchro getting hot.
Posted: Wed 03 Sep , 2014 9:43 am
by patrick oates
my machine has nov 82 on manufacturing tag.i used to be a machine tool fitter in my youth.i have had the machine about 5years.have been aware of it being a meshing prpoblem fro early.origanilly i put a 1 hp single phase motor but found it was causing the capacitor to burn out when in heaven use.i even blew the rubber belt on one occassion.i currently have original motor with my on steinmetz phase conversion hoping bigger power would overcome.i came accross this string by accident what it has done is confirmed to me what i already had figured out thank you for info it will come in useful
Re: Viceroy 280 synchro getting hot.
Posted: Wed 03 Sep , 2014 20:10 pm
by Pete.
I've made several, but right now I've started the biggest project of my career and I don't have time to make another. If you have a dividing head and mill they are easy to make.
viewtopic.php?f=50&t=2983&start=0
Re: Viceroy 280 synchro getting hot.
Posted: Thu 04 Sep , 2014 8:09 am
by rpwilson
patrick oates wrote:my machine has nov 82 on manufacturing tag.i used to be a machine tool fitter in my youth.i have had the machine about 5years.have been aware of it being a meshing prpoblem fro early.origanilly i put a 1 hp single phase motor but found it was causing the capacitor to burn out when in heaven use.i even blew the rubber belt on one occassion.i currently have original motor with my on steinmetz phase conversion hoping bigger power would overcome.i came accross this string by accident what it has done is confirmed to me what i already had figured out thank you for info it will come in useful
If it was made in late 1982, then it should have incorporated the later type gears which were modified from about the beggining of 1980 onwards to prevent this from happening. In which case, I don't know what to suggest is the cause of the heating, although it sounds as if new gears would be a good idea. The drawings are on the forum.
Richard
Re: Viceroy 280 synchro getting hot.
Posted: Thu 04 Sep , 2014 20:56 pm
by Pete.
I wouldn't count on it. Mine's also an '82 IIRC and I had the problem. Maybe it's old stock of gears or maybe the material they were cut from was affected over th elong term by the headstock oil but the problem was there.
Re: Viceroy 280 synchro getting hot.
Posted: Thu 04 Sep , 2014 23:42 pm
by rpwilson
Pete. wrote:I wouldn't count on it. Mine's also an '82 IIRC and I had the problem. Maybe it's old stock of gears or maybe the material they were cut from was affected over th elong term by the headstock oil but the problem was there.
Thats odd, mines about 1980 at a guess, and doesn't seem to have the problem. Admittedly I don't tend to use the top couple of speeds that much, or for very long, but I've spent quite a lot of time around 900 rpm and it seems OK. Maybe it did have the problem when young, and got new gears then. If I could be bothered, I'd take the cover off and calliper the gear diameters to check.
Richard
Re: Viceroy 280 synchro getting hot.
Posted: Thu 02 Oct , 2014 12:54 pm
by patrick oates
hi i am the one with tight gears.i have stripped headstock.the plastic gear i have has an outside dia of 5.699 as oppossed to what u quoted 5.563 so my od is 100 thou bigger can u check ur drawing again or is my lathe completley differerent.my serial number is 30857/syn/m.i was hoping to just shave the teeth but this will not fit with ur p.c.d.of5.563/5.559.appreciate ur assistance
Re: Viceroy 280 synchro getting hot.
Posted: Fri 03 Oct , 2014 9:29 am
by rpwilson
patrick oates wrote:hi i am the one with tight gears.i have stripped headstock.the plastic gear i have has an outside dia of 5.699 as oppossed to what u quoted 5.563 so my od is 100 thou bigger can u check ur drawing again or is my lathe completley differerent.my serial number is 30857/syn/m.i was hoping to just shave the teeth but this will not fit with ur p.c.d.of5.563/5.559.appreciate ur assistance
How curious. You can check the drawing yourself, its on the site here. They are BVS100/105 and 108, and there is an amendment sheet showing the reduction in diameters I quoted above. The original gear diameters were the theoretically correct sizes for 12DP. They are dated 1978, so if your machine is 1982, I suppose its possible there was a later change. Just as a check, as you have the gears out, the spindle gear should be 68T and the layshaft gear should be 65T.
There is an earlier drawing dated 1977, No.MVS 100/138 showing a 10DP gear with 54 teeth on the layshaft, but this has been crossed out, so presumably wasn't used. The headstock sectional drawing confirms the use of 68 and 65T gears.
Re: Viceroy 280 synchro getting hot.
Posted: Fri 03 Oct , 2014 12:29 pm
by Andy B
I'm not a plastics expert, but I do know that polymers are prone to swelling.
I
found some information that states "Quite some polymers absorb moisture from the environment. In time, this can cause swelling and affect part dimensions. ....... Machined parts, which have absorbed moisture and consequently have changed in dimensions, can be dried to regain their original machined size because moisture absorption is a reversible process. This is
preferably done in a vacuum oven until constant weight is achieved.....The drying time
obviously depends on the moisture content of the parts as well as on their thickness, but a minimum of
24 hours per each 3 mm of part thickness should be considered."
I'm wondering if home workshops induce particular problems. How many of us home shop owners keep them heated to a regular temparature and are not prone to condensation? So we've found a few hours to do some machining of an evening (warm machine). Temperature then drops rapidly as we lock up and the warm damp winter air inside the headstocks quickly becomes cold condensation, which coats the gears, etc. They then have a few days to sit there and absorb that condensate.
Such a duty cycle was probably not considered when the design was done.
Just a thought, but happy to be told it's a load of tosh by someone who does know about these things...
Andy
Re: Viceroy 280 synchro getting hot.
Posted: Sat 04 Oct , 2014 8:55 am
by patrick oates
[ have removed the gear and have shaved some about 10 thou of the od and taken asmall amount of each side asi found it was alittle tight in the selector locator.i then put the put lay shaft back in to find that this has definetley free the gear changing mechanism somewhat.i dont know wether to remove more as when i start running again heat will come into it as i am now convinced the gear is expanding when being run for long periods.100 thou bigger than the drawing states is still a bit of a mystery though.by the way it is possible to remove the lay shaft without removing the spindle you can just about squeeeze it round the front if you completley remove gear changing mechanism
Re: Viceroy 280 synchro getting hot.
Posted: Sun 05 Oct , 2014 2:01 am
by rpwilson
patrick oates wrote:[ have removed the gear and have shaved some about 10 thou of the od and taken asmall amount of each side asi found it was alittle tight in the selector locator.i then put the put lay shaft back in to find that this has definetley free the gear changing mechanism somewhat.i dont know wether to remove more as when i start running again heat will come into it as i am now convinced the gear is expanding when being run for long periods.100 thou bigger than the drawing states is still a bit of a mystery though.by the way it is possible to remove the lay shaft without removing the spindle you can just about squeeeze it round the front if you completley remove gear changing mechanism
The factory solution was 20 thou off the OD and cut the teeth a little deeper so the PCD was 20 thou smaller as well. The width was originally given as 7/8", but later given as .870" - .875". I'm still curious to know what the tooth count is though.
Re: Viceroy 280 synchro getting hot.
Posted: Mon 06 Oct , 2014 11:14 am
by rpwilson
patrick oates wrote:hi i am the one with tight gears.i have stripped headstock.the plastic gear i have has an outside dia of 5.699 as oppossed to what u quoted 5.563 so my od is 100 thou bigger can u check ur drawing again or is my lathe completley differerent.my serial number is 30857/syn/m.i was hoping to just shave the teeth but this will not fit with ur p.c.d.of5.563/5.559.appreciate ur assistance
Thinking about it, the only gear tooth count which makes sense for your diameter is 55T 10DP, but this doesn't correspond with any of the drawings I've seen for a 280 headstock. I've just taken the cover off mine and checked whats in there! The large plastic spindle gear is 68T, and the small steel one is 31T which correspond with the drawings. The OD of the large gear is 5.832", which is original diameter before the modifications, but it hasn't to date given any problems. I can't get at the layshaft gear to measure its diameter or do a reliable tooth count, but its certainly 12DP, so I'm presuming its in accordance with the drawings too.