Author Topic: Headstock > Tailstock alignment  (Read 2255 times)

Offline monty

  • iron
  • *
  • Posts: 3
Headstock > Tailstock alignment
« on: April 26, 2022, 04:56:27 PM »
I am comparatively new to woodturnig. I recently bought an old record lathe that I find pruduces expanding holes. Usind drill in tail stock hole is near on size at entry point but gets bigger as drill progresses deeper in to wood. Clearly the axis of the driiland headstock chuck are not in line. I was advised to check alignment by fitting a centre point in talstock and chuck and adjusting so that the 2 points kiss. however all this does is  make the drill entry point line up whith the material centre any drilled hole will still expand.
 A better  check and alignment method is needed.
some thing that causes a hole to expand by 0.005 inch over a 2 inch long pen blank is equivalent to 0.1 inch over 20 inches.
my way of checking used a clindrical laser sight held in a   tail stockdriil chuck at the tailstock shining on a target in the head stock chuck.  then moving the tal stock towards the head stock. ten reverse the arrangement laser at head target at tail stock. ifound the cheap ebay targetting lasers to be ok but a smaller spot diameter would improve ease of interprtation. A one time I had a cheap small buiders level that had a laser in it that gave a fine cross image the would be ideal.
My lathe is on tubuler metal legs which stand on a wood frame work with wheel casters for mobility. My current interprtation of the laserspots is  the bed bars are skewed , the tail stock  and head stock are not paralle . I think the lathe has been put together working up from the wood frame. Eventualy I will strip it and reassemble the lathe on a bench then recheck for miss alignment.

Offline Valkrider

  • Administrator
  • bronze
  • *****
  • Posts: 133
    • TurnLincs
Re: Headstock > Tailstock alignment
« Reply #1 on: April 27, 2022, 07:37:34 AM »
@Monty I have split this off into a new topic as it is about alignment of your particular lathe rather than about specifically drilling resin blanks.

When I had a Record lathe to overcome a similar problem I replaced the tubular bed bars with solid steel ones that I purchased from a local steel stockholders. This had two advantages it considerable increased the dead weight of the lathe and also corrected the misalignment.

Offline Derek

  • platinum
  • *****
  • Posts: 1369
Re: Headstock > Tailstock alignment
« Reply #2 on: April 27, 2022, 08:16:54 AM »
Before you start going out and buying anything make sure that the two bars are level to each other along the length as well as across the bars front to back and that the points that the bars are placed into are clean top and bottom as well as the bars.
As any twist in the set up can put things out. This can also happen to the cast bed types which people think can't happen but it can.

I know THIS is for a metal working lathe set up but the principle is the same. You may not need a level of the precision he is using as metal working lathe do tend to get used for a more precise accuracy   

Offline Bill21

  • platinum
  • *****
  • Posts: 901
Re: Headstock > Tailstock alignment
« Reply #3 on: April 27, 2022, 09:18:21 AM »
Some folks swear by these, not sure it will fit your lathe though?

https://www.axminstertools.com/axminster-lathe-alignment-centre-2mt-102427

Offline Duncan A

  • bronze
  • ***
  • Posts: 175
Re: Headstock > Tailstock alignment
« Reply #4 on: April 27, 2022, 10:31:51 AM »
You don't say what model of lathe you have. The CL3, in some incarnations at least, came with solid bed bars which will help stiffness - it would be helpful to know whether your bars are solid or hollow.

All lathes will twist if not stood carefully on a flat surface with equal leg lengths - worth checking.

Record lathes with round bed bars are assembled with cast iron clamps to hold the bars in position - and those clamps must all be the same way round. Easy to get wrong, if not in possession of a manual. There's a small bump on the castings to indicate front and back. Doesn't matter which way round as long as they're all put the same way round.

Duncan

Offline Bill21

  • platinum
  • *****
  • Posts: 901
Re: Headstock > Tailstock alignment
« Reply #5 on: April 27, 2022, 01:28:33 PM »


Record lathes with round bed bars are assembled with cast iron clamps to hold the bars in position - and those clamps must all be the same way round. Easy to get wrong, if not in possession of a manual. There's a small bump on the castings to indicate front and back. Doesn't matter which way round as long as they're all put the same way round.

Duncan

I’ve not got one but worth knowing for some, thanks for posting.  ;)

Offline monty

  • iron
  • *
  • Posts: 3
Re: Headstock > Tailstock alignment
« Reply #6 on: May 19, 2022, 01:50:46 PM »
Thanks for the advice, and sorry it has taken me so long to respond.
The lathe has heavy solid bars.
I have learnt that this individual lathe was previously known to produce drilled holes that grew in diammeter as the drill went further into the wood.
At the moment I believe the bed bars are twisted probably as a result of being assembled onto a wooden frame with casters for mobility.
that is to say that the lathe was not assembled on a known firm flat surface.
My main interest is bowl rather than spindle work so for the moment I will live with the problem. I am also slowly building a "new " workshop. When  things are moved to the new work shop I will strip the lathe  and carefully reassemble it.
IT is reassuring to know that the forum provides access good advic so rapidly, thans again.
Monty

Offline Wood spinner

  • platinum
  • *****
  • Posts: 727
Re: Headstock > Tailstock alignment
« Reply #7 on: May 19, 2022, 05:23:20 PM »
Also the front bearings eventually wear out , If you disconnect the lathe from the power , Grab hold of the chuck and push / pull
strongly, also up and down , If you have any play this could cause problems , the front bearing is adjustable but in the end you need a new spindle / bearing / belt kit , these are available to buy