Trying to fit a hand-rail

by Richard

Hi there,

I am trying to fit a hand-rail to a newel post in my house. When measuring for the height, do I come up 900mm from the first step to the top of the handrail?

Where do I messure the 900 from? How do I get the handrail to run level with the stair string so that the spindles are all the same measurements? I have 1800mm between my post and the wall so if

I divide that by 112 it gives me 16.07 so dose that mean I need 16 spindles then? How do I calulate the space even if it is 16 spindles - I know you said cut all the spindles and put them in at the bottom of the stairs and then measure from the top of the spindle to the buttom of the post upstairs horizontally so what do I do with that measurement to get the spindles the same distance and keep it to the 100mm or under?

Thanks for your help,


Comments for Trying to fit a hand-rail

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Apr 15, 2015
Hi Anonymous,
by: Gary

Hi there,

The formula for calculating how many spindles you need to buy/install is discussed more on page

It is to be used as a guide, but the reason you divide by 112mm is because that is the formula to give you the correct number of 32mm turned spindles for that specific opening in the balustrade. Try it out, for example you have a 1000mm opening:

1000/112 = 8.9: round up to 9 spindles needed.
9 x 32mm = 288mm: the total horizontal size of those spindles if bunched together.
(1000-288) = 712: the remaining gap to be divided by 10 because there will be one more gap than there are spindles
712/10 = 71.2mm. This is the horizontal gap between spindles, which generally needs to be below 100mm. If you have turned ornate spindles the gap will get larger than 71.2mm as the spindles and possibly also the newel post get narrower in places.

Now do the same caluclation with only 8 spindles and the gap will be 82.7mm. This would be OK for square spindles but most likely not for turned spindles as the gap may exceed 100mm at the narrowest points.

Also, the reason I dont take the length of the miter, is because that doesn't give you the horizontal gap that the regulations stipulate you must adhere to. What this means is if you work it out your way (diagonally), you will get the length of the packing piece/spacer you need to cut. Then you will need to get one or two spindles and position them at that dimension. Then you will need to take a tape measure and check to see if horizontally you have less than a 100mm gap. There is more work involved in that process - I'd have half the staircase finished by then ;-)

You can do it whichever way suits you personally. My way will tell you straight away what the horizontal gap is between square parts of the spindle so you will know instantly if that is over 100mm mor not.

Does that make sense?


Apr 15, 2015
stair fitting
by: Anonymous

Hi , with regards of spindle space. Why divide by 112mm . Also I was told before that you take the miter length of the spindle eg 53mm and not thickness eg 45mm

Aug 12, 2011
Fitting a hand rail
by: Anonymous

I'll answer each part of your question seperately!

1:How to measure the height of the handrail?

The 900mm hand-rail measurement must be taken from the pitch line, which is the line created by the tip of each step/tread. If you put a spirit level or straight piece of timber on top of the treads so it just touches the tip of each nosing (rounded off part) then the bottom edge of the level will be the pitch line. I normally put a level on the treads and transfer the line onto the post, measure up 910mm to be safe and square it round to the front of the post where the hand rail will fall. That mark is the top edge of the handrail.

2:Getting the handrail to run level/parallel with the string?

The easiest way to do this is set a bevel to the angle of your stairs and then cut this angle onto your handrail. Take the offcut and hold it up to the 910mm mark from step 1 above. Now you can mark the underside of the hand rail groove onto the post, which will give you the length a spindle needs to be up from the base rail. Next, cut the same angle onto the bottom of a spindle. Put the spindle into the base rail up against the post and transfer the length onto it. Now you can cut a spindle to the right length to hold the handrail at 910mm, cut an extra one and clamp one to each post - top and bottom. Once these are clamped you have two spindles to rest your hand rail on whilst you are fitting it into position and when you fix it to the posts.

3:Calculating how many spindles you need

If you divide by 112mm and arrive at 16.07 you must round that number up, so you in fact need 17 spindles. Cut them all exactly the same as the two in step 2 and place all the spindles in the bottom. Measure the remaining space horizontally, and then divide that measurement by 18 (if you have 17 spindles there will be 18 gaps). That will give you the horizontal distance less than 100mm between each spindle. This is not the length of the infill to cut though, you must glue and pin a spindle this distance away from the newel post then cut the angle on the infill and hold it in position and mark it's length. Cut a few of them and try them before cutting enough to get past halfway. There is a step-by-step spindle installation guide at the spindle spacing page and loads more help installing handrails here.

Hope that helps!


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