Reamer 2.38 mm

H7 Precision in Every Pass: The Straight Reamer That Makes a Difference in the Slot Workshop

When a tenth of a millimetre matters — and it always does in slot car preparation — a good straight reamer is worth more than any shortcuts. The 2.38 mm Reamer from Sloting Plus (SP143726) is made from HSS (High Speed Steel) and operates with H7 tolerance, ensuring that the reamed hole is precisely sized throughout its length, without variations or surprises.

Technical Features

• Material: HSS (High Speed Steel)
• Diameter: Ø2.38 mm
• Tolerance: H7 (precise fit)
• Contents: bag with 1 unit
• Application: aluminium and plastic

Why a Straight Reamer and Not a Tapered One

The difference between a tapered reamer and a straight one is significant: it’s the difference between a correct fit and a discarded part. Sloting Plus is very clear on this, which is why their entire range of reamers features a straight edge. Here are the reasons:

1. Constant diametral precision. The cutting edge maintains exactly the same diameter from the start to the end of the cut. There is no progressive variation.
2. Accuracy throughout the length. The reamed hole is precisely sized from start to finish. It will never be tapered.
3. Reliable axle fit. The axle is held securely along its entire length, not just at a single contact point.
4. Zero risk of oversizing. With a tapered reamer, it’s very easy to excessively enlarge one end of the hole and compromise the part. With this straight model, control is total.

Applications in Slot Car Preparation

This Ø2.38 mm reamer is particularly useful for reaming holes in brackets, motor mounts, plastic chassis, or machined aluminium parts that need to accommodate an axle or pin with a fine fit. If you work with precision parts — whether in competitive categories or club preparations — having the reamer of the exact size prevents forcing components or, worse still, discarding parts due to a poorly reamed hole.

The H7 tolerance is the standard reference for axle fits with minimal controlled clearance, ideal for axles that must rotate or slide smoothly but without perceptible play.

Recommended Mounting and Use

To achieve the best results, introduce the reamer progressively and with a smooth rotary motion, without forcing. In materials like plastic, excessive pressure can generate heat and deform the part. In aluminium, a few drops of cutting oil or even WD-40 help achieve a cleaner finish and prolong the tool's life.

Store the reamers protected, separated from each other, to preserve the cutting edge. A damaged edge does not guarantee H7 tolerance and can ruin the part instead of improving it.

Frequently Asked Questions

What materials is this reamer designed for?

Sloting Plus explicitly states: aluminium and plastic. These are the most common materials in slot preparation parts. It is not designed for hardened steel.

What does H7 tolerance mean?

H7 is an ISO tolerance designation that indicates a fit with very reduced and controlled clearance. It is the standard tolerance for holes that must accommodate axles with fine sliding fits, without noticeable play but without interference.

How does it differ from a tapered reamer?

A tapered reamer enlarges the hole progressively and does not guarantee the same size along the entire length of the bore. The straight reamer, on the other hand, works with a constant diameter from end to end, eliminating the risk of taper and oversizing one side.

How many units does the product include?

The product is presented in an individual bag with 1 unit.

Is it compatible with a standard chuck or drill chuck?

Yes. The shank of the reamer can be held in any chuck or drill press or handheld drill with the appropriate opening. It can also be used with a precision drill handpiece for more delicate work.

Can it be used in a pillar drill?

Yes, and in fact, the pillar drill is the most recommended option when perfect perpendicularity is needed. It allows for much more precise control of speed and downward pressure than by hand.

The Sloting Plus SP143726 is a 2.38 mm straight HSS reamer with H7 precision tolerance, designed for use on aluminium and plastic slot car parts. Unlike tapered reamers, this straight-flute tool delivers consistent diameter along the full length of the bore, ensuring precise axle fitment without any risk of taper or oversizing. An essential workshop tool for slot car preparation, club racing and competitive tuning.